Electrical Breakdown Properties of Clay-Based LDPE Blends and...

Research ArticleElectrical Breakdown Properties of Clay-Based LDPEBlends and Nanocomposites

Mostafa Eesaee 1 Eric David 1 Nicole R Demarquette1 and Davide Fabiani2

1Mechanical Engineering Department Ecole de Technologie Superieure Montreal QC Canada2Department of Electrical Electronic and Information Engineering University of Bologna Bologna Italy

Correspondence should be addressed to Mostafa Eesaee meesaeeyahoocom

Received 5 September 2017 Revised 20 November 2017 Accepted 27 November 2017 Published 11 January 2018

Academic Editor Alessandro Pegoretti

Copyright copy 2018 Mostafa Eesaee et alThis is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

Microstructure and electrical breakdown properties of blends and nanocomposites based on low-density polyethylene (LDPE) havebeen discussed A series of LDPE nanocomposites containing different amount of organomodifiedmontmorillonite (clay) with andwithout compatibilizer have been prepared bymeans ofmelt compounding Two sets of blends of LDPEwith two grades of Styrene-Ethylene-Butylene-Styrene block copolymers have been prepared to form cocontinuous structure and host the nanoreinforcementA high degree of dispersion of oriented clay was observed through X-ray diffraction scanning and transmission electronmicroscopy This was confirmed by the solid-like behavior of storage modulus in low frequencies in rheological measurementresults An alteration in the morphology of blends was witnessed upon addition of clay where the transportation phenomenon tothe copolymer phase resulted in a downsizing on the domain size of the constituents of the immiscible blends The AC breakdownstrength of nanocomposites significantly increased when clay was incorporated The partially exfoliated and intercalated clayplatelets are believed to distribute the electric stress and prolong the breakdown time by creating a tortuous path for charge carriersHowever the incorporation of clay has been shown to diminish the DC breakdown strength of nanocomposites mostly due to thethermal instability brought by clay

1 Introduction

It has been more than eight decades that synthetic polymershave been used as solid electrical insulatingmaterials becauseof their excellent dielectric properties the most importantof which is the high dielectric breakdown strength Whena dielectric is subjected to a rising voltage with a highenough applied electrical field the electrical pressure willeventually overcome the insulating material and electricalcharge carriers will flow Current flow behavior through aninsulator is not linear as in conductors and practically noelectrons will flow below a certain threshold level abovewhich current will gain sufficient kinetic energy and forciblyruns through the material Electrons will multiply as a resultof the ionization of the collision process electronic conduc-tion takes place and breakdown occurs This mechanism isknown as avalanche process [1 2] and the dielectric strengthis defined as the highest voltage the insulator withstandsbefore breakdown divided by its thickness However this is

not the only known mechanism and breakdown may occurin advance of electron avalanche by insulation melting due totemperature rise (thermal breakdown) and enhanced electricstress when the insulation thickness is mechanically reduced(electromechanical breakdown) or due to partial discharge[3ndash6] In reality the mechanism of dielectric breakdownis more complicated in many polymers and preexistingdiscontinuities also contribute to the cumulative breakdownIt was found out that impurities defects and degradationcaused by electric field or heat will accelerate the failure[7] Extensive works have been done to understand thebehavior of polymers towards electrical breakdown whichhas led to considering several factors such as thicknesssurrounding medium pressure and temperature all alongwith the complicated morphology and structure of polymerswhich make the understanding of breakdown process verydifficult

One proposed solution to improve the breakdownstrength of polymers consists of adding a reinforcing

HindawiJournal of NanomaterialsVolume 2018 Article ID 7921725 17 pageshttpsdoiorg10115520187921725

2 Journal of Nanomaterials

inclusion as fillers (composites) Despite improvements inmechanical and thermal properties micro inclusions arebelieved to decrease the breakdown strength of polymers asthey may act as defects [8] Consequently nanofiller inclu-sions have been introduced recently to overcome the negativeeffects [3 9] thus creating a new area of materials callednanometric dielectrics or nanodielectrics [10] Nanoparticleswhich may be chemically modified with different approachesin order to have polar or nonpolar functional groups ontheir surface have shown very promising results [11] It iswell known that they have a great influence on breakdownproperties of polymers especially by the change in mor-phology of the semicrystalline polymers [12] They reducethe internal field [13] and alter the space charge distributionwithin the polymer matrix [14] Furthermore the interfacebetween polymer and nanoparticle plays a crucial role in thedielectric breakdown performance [15 16]The final obtainedmorphology and the physical and chemical characteristicsof the interface are greatly influenced by the dispersion andlocalization of nanoparticles and the nature of both phaseswhich will eventually influence the breakdown process bychanging the microscale aspects that is traps free volumeand carrier mobility [17] Therefore considerable attentionsmust be paid to tailor the interface with proper physical andchemical methods to obtain improved dielectric breakdownproperties [18 19]

Another well-established approach to develop new mate-rials is polymer blending [20] Since usually polymers havelow mixing entropy most polymer pairs tend to make animmiscible blend [21] During the mixing process and atrest the dynamic interplay between rheological phenomenadetermines the final morphology of the blend When havingdifferent mixing proportion the minor component tends todistribute all over the major phase as droplets Howeverin a narrow range of composition with proper processingthe blend microstructure can turn into cocontinuous distin-guished by amutual interpenetration of the two componentsThis type of microstructure is well-known for its tunable andsubstantial combination of functional and structural proper-ties but is hard to achieve [22] It has been well-establishedthat nanoparticles can be adopted to stabilize themorphologyof immiscible blends [23ndash25] However this approach has notbeen fully employed to discover the potential improvementsin electrical breakdown properties of polymers

In this paper attempts to evaluate the short-term AC andDC electrical breakdown properties for clay-based nanocom-posites of low-density polyethylene (LDPE) have been pre-sented alongside with observation of the morphology ofthose materials Also the possibility of using a binary blendto achieve a tailored dispersion of nanoclays to result in animproved AC and DC electrical breakdown was evaluated

2 Experimental

21 Materials and Processing Commercially available pre-mixed LDPEclay masterbatch (nanoMax-LDPE) contain-ing 50 organomodified montmorillonite (O-MMT) wassupplied from Nanocor and used as the source of the nanor-einforcement The masterbatch was further diluted with

low-density polyethylene (LDPE) supplied from Marplexin powder form with a density of 0922 gcm3 and MFI of09 g10min (190∘C216 kg) to the desired concentrations ofclay Maleic anhydride grafted linear low-density polyethy-lene (LLDPE-g-MA) was supplied from DuPont (FusabondM603) and has been used as a compatibilizer It has a densityof 0940 gcm3 and MFI of 25 gmin and is being referred toasMA in thismanuscript Two series of nanocomposites wereprepared with and without 5wt of the compatibilizer withconcentration profile of clay being set as 1 25 5 10 and 15

The same procedure was used to prepare blends andnanocomposites of LDPE with two grades of polystyrene-b-poly(ethylene-co-butylene)-b-polystyrene (SEBS) thermo-plastic elastomer supplied from Kraton G1652 and FG1901The former with a MFI of 5 (230∘C216 kg) based on ASTMD1238 (as declared by the supplier) is referred to as SEBS inthis manuscript The latter with a MFI of 22 which contains14ndash2wt of maleic anhydride (MA) is referred to as SEBS-MA Both grades contain 30wt fractions of polystyrene(PS) block in their structure and have a density of 091 gcm3

Melt compounding via extrusion process has been per-formed using a corotating twin-screw extruder All materialswere dried prior to extrusion in a vacuum oven at 45∘C forat least 36 h andmanually premixed A temperature profile of145ndash170∘C was set from hopper to die The pellets obtainedwere press-molded using an electrically heated hydraulicpress into thin plates with various thicknesses regarding thefuture characterization Samples were first preheated for 5minutes and then hot-pressed at 155∘C (165∘C for blends) foranother 5 minutes under the pressure of 10MPa Press platesthen were water-cooled with a rate of 10∘C per minute tothe ambient temperature Table 1 represents a summary ofthe composition of the final blends and nanocomposites Incase of blends the mass fractions of the two phases are setequal Note that the nominal percentages of clay have beenused since the thermogravimetric analysis (TGA) showed(not shown here) that the actual weight percentage of clay inthe masterbatch is 32wt

22 Characterization The morphology of the as-obtainednanocomposites was characterized by high resolution scan-ning electron microscopy (SEM) using a Hitachi SU-8230Field Emission-STEM microscope Samples were cryogeni-cally cut and sputtered with a 20 nm layer of platinum usinga Turbo-Pumped Sputter Coater (Q150T S) prior to theobservation Solvent extraction has been used to investigatethe microscopic structure of the blends Some samples wereheld in Toluene for 24 h while being gently stirred at roomtemperature and then washed with alcohol before SEMobservation

Transmission Electron Microscopy has been also con-ducted With respect to SEM it employs electron beaminstead of light beam It has been done using a FEI TecnaiG2F20 STEM operated at 200 kV The device is equippedwith a Gatan Ultrascan 4000 4k times 4k CCD Camera System(Model 895) Samples were cryogenically cut to create thinlayers that allow electron beam penetration The point-to-point and line resolutions of the TEM are respectively024 nm and 017 nm

Journal of Nanomaterials 3

Table 1 Composition and nomenclature of LDPESEBS blends and nanocomposites

LDPE (wt) Clay () MA (wt) SEBS (wt) SEBS-MA (wt)LDPEnC (100 minus 119899)lowast 119899 - - -LDPEMAnC (95 minus 119899) 119899 5 - -LDPESEBS 50 - - 50 -LDPESEBS-MA 50 - - - 50LDPESEBS5C 475 5 - 475 -LDPESEBS-MA5C 475 5 - - 475lowast119899 = 1 25 5 10 and 15

Sample

HV AC

Surrounding medium

Electrodes

4m

m

(a)

HV DC

60mm

30mm

7m

m(b)

Figure 1 Electrical breakdown measurement setup for (a) AC short term and (b) DC short term

X-ray diffraction has been employed to evaluate thedegree of dispersion and intercalationexfoliation of thenanoclay using PANanalytical XrsquoPert Pro with K120572 radiation(120582 = 1542 A) Accelerating voltage and electrical currentwas set to 40 kV and 40mA respectively The scanning wasconducted from 2∘ to 10∘ with a step size of 0102∘ and thecounting time was 400ms per step Braggrsquos law was used tocalculate the intercalate spacing (d

001) as

2119889 sin 120579 = 120582 (1)

where 120582 is the wavelength of the X-ray radiation used 119889 isthe distant between the diffraction of lattice plans and 120579 isthe diffraction angle measured [26]

The morphological data were further enriched by con-ducting rheological measurement at 160∘C via a strain-controlled rheometer (MCR 501 Anton Paar) First a strainsweep was carried out to determine the linear viscoelas-tic range then small amplitude oscillatory shear (SAOS)tests were performed in the frequency range from 001 to300 radsdotsminus1 Samples in parallel plate geometry with diameterof 25mm were used in a 1mm sample gap

The AC short-term breakdown test was conducted tomeasure the dielectric strength of the samples using a BAURDTA 100 device where the samples are gently held betweenthe electrodes (ball-type 4mmdiameter) while all immersedin insulating oil (Luminol TR-i Petro-Canada) to avoidflashoverMethodA fromASTMD149was chosen accordingto which the ramp was set to 2 kVs and continued untilfailure of the sample The test was performed at ambienttemperature and the insulating oil was dried in vacuum oven

for a minimum of 48 h Twenty specimens were tested foreach sample Each time before changing the sample the oilwas removed and fully replaced and the electrodes werecleaned A thickness of 140 120583m was used for the breakdowntest while to find out the role of thickness on the breakdownstrength variation the test was also conducted for two otherthicknesses (200 120583m and 300 120583m) for LDPEclay nanocom-posites A power law relationship was used to correct themeasurement data as a result of the nonuniformity in thethickness of specimens as discussed in [27]

The same approach was used to measure the DC break-down strength of the samples having 200 120583m thicknessSpecimens were placed between a spherical electrode on top(30mm diameter) and a disk-shape electrode on the bottomThe diameter of the lower electrode was 60 with a roundingradius of 7mm Electrodes were placed in a container whileimmersed in mineral oil The specimens were subjected toa voltage raise of 5 kVs Eight specimens were tested foreach sample between which the oil was renewed completelyLabView software was used to computerize the measuringsystem Figure 1 depicts a schematic representation of themeasurement setups used for both high voltage AC and DCbreakdown tests A commercially available software was usedto retrieve the data for both AC andDC breakdown strengthsbased on two-parameter Weibull distribution

3 Results and Discussion

31 X-Ray Diffraction (XRD) Figure 2 shows the X-raydiffraction spectra for the LDPE clay nanocomposites This


Inte

nsity

(au

)

LDPE15CLDPESEBS-MA5CLDPESEBS5CLDPEMA5C

LDPE5CLDPE1CLDPEclay masterbatch

2 3 4 5 6 7 8 9 10 1112 (degree)

X-raysource

(a)



Inte

nsity

(au

)

2 3 4 5 6 7 8 9 10 1112 (degree)

X-raysource

(b)

Figure 2 X-ray diffraction pattern for LDPE nanocomposites (a) parallel emission and (b) perpendicular emission

technique allows us to determine the interlayer distance ofnanoclay by utilizing Bragrsquos law The identification of thenanocomposite structure can be done via monitoring theintensity shape and position of the basal reflection peaksThe layers of the silicates usually form stacks with a regularvan derWaals gap called the interlayer or the gallery A singlelayer has a thickness around 1 nm but tactoids formed byseveral layers can reach up to several hundreds of micronwhen forming stacks [28] According to Bragrsquos law a shift ofdiffraction peak towards lower diffraction angle is a sign ofan increase in the interlayer spacing as a result of polymerintercalation Higher extent of polymer intercalation wouldresult in a greater shift towards lower value of 2120579 signalinga better dispersion of the clay nanoplatelets [28 29] Thisincrease in interlayer spacing also decreases the periodicitywhich reflects a reduction in the intensity of the peak

The XRDmeasurements were conducted in two differentdirections having the radiation starting parallel and per-pendicular to the surface of the sample As can be seen inFigure 2(a) in parallel emission there is a peak at 2120579 of 634corresponding to an interlayer spacing of around 139 nm andno evident sign of the primary diffraction peak (d

001) while

the corresponding peak for masterbatch occurs at 2120579 of 726showing a shift of diffraction peak for nanocomposites to

lower degrees originating from the increase in the interlayerspacing during the melt mixing That means at least oneextended polymer chain is intercalated between the stacks ofsilicate layers As expected the intensity of the peak increaseswith the increase in the amount of clay incorporated Forsample containing 5wt ofMA (LDPEMA5C) the diffrac-tion peak occurs at the same place but is broader than theoriginal nanocomposite (LDPE5C) This broadening of thediffraction peak suggests that the degree of dispersion of theclay within the polymer matrix is further improved possiblydue to the polar interactions between the maleic anhydridegroups in the compatibilizer and the hydroxyl groups ofclay and the increase in the shear stress because of the lowmolecular weight of MA This may end up in formationof covalent bond and facilitate the penetration of polymerchains into the galleries of clay [30]

When the direction of the radiation is normal to thesurface of the sample (Figure 2(b)) nanocomposites patternsshow some fluctuations but no clear peak can be recognizedThe same pattern is seen for themasterbatchThis is probablydue to the orientation of the clay layers parallel to the surfacewhen molded in hydraulic press under high temperature andhigh pressure into thin platesThis was possible since the finalthickness of the samples was all less than 300 120583m and under


(a)

(b)

Figure 3 SEM (a) and TEM (b) micrographs for LDPE5C

pressure the molten polymer had to flow in the directionsperpendicular to the applied pressure Thicker samples havenot been prepared however it is expected that the anisotropyof the clay is maximum under the highest applied pressure[31]

However XRD do not fully reveal the spatial distributionof the layered silicates besides some layered silicates do notshow observable basal reflectionsTherefore themorphologyof the nanocomposite must also be evaluated by other meansof spectroscopy

32 Scanning (SEM) and Transmission Electron Microscopy(TEM) Thedispersion of nanoclaywas examined using SEMand TEM Figure 3 shows both techniquesrsquo micrographs ofLDPE nanocomposites reinforced with 5 clay Stacks ofclay tactoids with a high degree of aspect ratio and surfacearea are visible in both cases They are uniformly distributedthroughout the polyethylenematrix A noticeable orientationof clay stacks is visible which is in agreement with the XRDresultsThe distances between clay sheets are huge and stacksare totally separated from each other Moreover there are

clear signs of polymer intercalation in some clay stacks as canbe seen in TEM micrograph However sheets of clay are notfully inlaid within the LDPE matrix and despite the achievedseparation a noticeable amount of gaps is visible from SEMmicrograph in the interfacial areaThis hints that even surfacemodification of the clay does not fully repair the poor bondand weak interaction between hydrophilic silicate layers withthe hydrophobic polyethylene

The SEM micrographs of blends and their nanocompos-ites are shown in Figure 4 alongsidewith their correspondingimages where the SEBS phase is selectively removed usingsolvent extraction process The white areas are believed tobe the elastomer phase When SEBS is blended with LDPE(a-d) a random micrometric mixture of the two phases isvisible which is revealed from the solvent extracted images tobe a cocontinuous structure When SEBS-MA is used (endashh)the resultant is still a cocontinuous structure However theelastomer phase is less evident possibly because of the opticaleffects of MA grafted to the SEBS molecules

Due to the complexity of the images it is hard to pointout the possible stacks of clay but a noticeable change in


(a) (b)

(c) (d)

(e) (f)

(g) (h)

Figure 4 SEM micrographs of LDPE blends before and after solvent extraction (a) and (b) LDPESEBS (c) and (d) LDPESEBS5C (e)and (f) LDPESEBS-MA and (g) and (h) LDPESEBS-MA5C

the structure of both blends is obvious when 5 of clay isincorporatedThenanocompositesmaintain the cocontinuitybut it goes to smaller dimensions Regarding the elastomerphase the curves and arcs are much smaller in the presenceof nanoclay Also the black holes in the solvent extractedimages representing the absence of the elastomer phase havelower diametersThis downsizing effect of clay on the domainsize of the constituents of the immiscible blends havingcocontinuous structure has been previously reported [23 32]

That means the introduction of clay into the blend actuallyalters the morphology of the blends Clay may prevent orslowdown the coalescence phenomenon by acting as solidbarriers or can act as compatibilizer and interact with thetwo components simultaneously [33 34] Even under weakinteraction clay has been reported to act as coupling agentamong the polymer constituents [35 36]

Regarding the SEM images of LDPESEBS-MAblend andnanocomposite (Figures 4(e) and 4(g)) the surface texture


appears to be more homogenously dispersed and domainsare stretched alongside each other signaling a smooth andstrong interaction between the two polymersThis is probablydue to the refinement of the SEBS backbone by graftedMA Lower viscosity ratio of SEBS-MA also would inducea change of hydrodynamic stresses during the mixing andenhance the refinement by improving the phase separationkinetics and decreasing the interfacial tension [37] Howeverthe immiscibility in the blend comes from the polystyreneblocks of the elastomer phase which is highly incompatiblewith LDPE Therefore the refinement of ethylene-butylenemidblock of the elastomer cannot dramatically change itsmixing behavior It would however make the elastomerphase more attractive towards clay promote the melt inter-calation process and accelerate the clay transportation

It appears that the localization of clay and its possi-ble selective interaction with the blend matrix constituentscontrols the morphology of the final nanocomposite It iswell-recognized that the localization of the nanoparticles ismostly determined during the mixing stage and further inthe melting process In low viscosity blends the thermo-dynamic preferential attraction between nanoparticles andblend constituents determines the localization of nanoparti-cles whereas for higher viscosity kinetic parameters such assequence of feeding and viscosity difference of the compo-nents are dominating

Direct feeding was used to prepare the samples howeverclay was available in the form of masterbatch meaning that ithad already been mixed with polyethylene This order of thecomponent mixing directly influences the clay distributionand preferential localization since polyethylene is the lessfavorable phase for clay to be distributed in due to thepolarity difference and thermodynamic attraction In a binarysystem of clay and SEBS matrix it was shown that claynanoparticles would locate into polystyrene (PS) cylindersof SEBS and further into poly(ethylene-co-butylene) (PEB)blocks in case of SEBS-MA [38] With a narrow range ofviscosity difference between the two polymer componentsthe interfacial energy becomes the main parameter deter-mining the direction of redistribution of the nanoparticle[39ndash41] Therefore there is a great chance that during themelt processing clay would be transported from polyethylenephase to the elastomer phase A similar phenomenon wasreported for carbon black nanoparticles and assumed to bethe only feasible approach [42 43] Also in another studyEliaset al [44] reported that the hydrophilic silica would transferfrom polypropylene to polystyrene phase during the meltmixing Later they reported the same mechanism for silicain polypropyleneethylene vinyl acetate (EVA) blend [45] Asa result of this transportation the coalescence mechanism isobstructed and the polymer domains shrink into smaller size

To evaluate this hypothesis TEM observation was alsoconducted on LDPESEBS5C sample as illustrated inFigure 5 As can be seen the orientation of clay sheets ishugely affected by the cocontinuous structure of the blendmatrix Clay stacks and separated layers can be spottedin both phases that confirm the nanofillerrsquos transportationhowever they are mainly located in the interface This wasexpected since the mixing time do not exceed a few minutes

SEBSLDPEClay

Figure 5 TEM micrograph of LDPESEBS5C (schematic phaserepresentation on top)

and is well lower than the Brownian diffusion time requiredfor clay to reach the preferred localization Also the highaspect ratio of clay reduces the speed of the transportationFor the same reason the chance of clay getting stuck in theinterface of the two phases is high where it also happens to bethe area with low interfacial energy Helal et al [46] estimatedthe wetting coefficient of ZnO nanoparticles in PESEBS-MAblend and reported that the nanoparticles should be mainlylocalized in SEBS-MA phase and probably at the interfacePESEBS-MAThis conclusion can also be applied here sincethe values of surface tension for ZnO and organomodifiedclay are close to each other

33 Rheological Properties To have more insight of thedispersion of the clay and the morphology of the blends andnanocomposites at larger scale Small Amplitude OscillatoryShear (SAOS) test has been conducted


LDPELDPE10CLDPE15CLDPEMA15C

LDPESEBSLDPESEBS5C

1E + 02

1E + 03

1E + 04

1E + 05

1E + 06

Stor

age m

odul

us (P

a)

01 1 10 100 1000001Angular frequency (rads)

LDPESEBS-MALDPESEBS-MA5C

Figure 6 SAOS measurements of LDPE SEBS blends and clay-reinforced nanocomposites storage modulus (1198661015840) as function ofangular frequency (120596)

Figure 6 shows plots of storage modulus of LDPE andits blends and nanocomposites as a function of angularfrequency For neat LDPE a predictable terminal behavioris seen with a high slope and drop of the modulus atlow frequencies Similar behavior was obtained with theaddition of nanoparticle up to 5 of clay where the plotsof nanocomposites overlap the LDPE (not shown here) andshow a homopolymer-like terminal behavior This hints arelatively weak interfacial interaction of clay with LDPEas was seen in SEM micrographs Therefore it is believedthat within this range the nanoparticlesrsquo contribution islimited to the hydrodynamic effect At 10 loading of clay(LDPE10C) the curve slightly shifts to higher values At15 loading of clay (LDPE15C) the increase is much largerand a plateau of storage modulus can be seen at low fre-quencies At this point the rheological percolation thresholdhas been reached and nanocomposite exhibits a liquid-solidtransition (LST) [47 48] The increase of elasticity can beoriginated from the three-dimensional network formed bythe clay-clay andor clay-LDPE interaction and the resultinglimitation in the molecular motion of the polymer whichinclines the plot towards a solid-like response [49 50] Asimilar behavior has been reported for nanoparticles otherthan clay [51ndash55] In case of the nanocomposite containingcompatibilizer (LDPEMA15C) this change of behavior ismore pronounced The low-frequency solid body responseof LDPEMA15C nanocomposite is stronger than that ofLDPE15C MA with lower molecular weight can easily enterthe clay galleries and form a stronger interaction with thehydroxyl group on the clay layer [56 57]This compatibilizingeffect of MA increases the degree of interfacial interactionbetween LDPEMAmatrix and clay tactoids As a result dueto the enhanced polymer intercalation the effective volumefraction of clay increases and consequently higher degree of

clay dispersion is achieved This is in accordance with theXRD pattern

A general look at the storage modulus plots for blendsand their nanocomposites represents a consistent increasethrough the whole range and especially in low frequenciesDue to the high level of heterogeneity in block copolymerstheir rheological behavior is strongly related to the phase-separated morphology and it is brought into the blend Thelow-frequency increase in the storagemodulus is as a result ofthe characteristic nonterminal behavior of block copolymersandor possible presence of droplets that deform and increasethe elasticity [58] It has been proposed that the dominantparameter in determining the rheology behavior of cocontin-uous blends is the componentsrsquo contribution and it is rarelydependent on the morphology [59] In fact in the case ofLDPESEBS blend this factor is either so strong that the intro-ducing 5 of clay does not appear to change it or still thereis a weak interfacial interaction between clay and the blendmatrix similar to the binary nanocomposite In the matrixof LDPESEBS-MA however clay noticeably enhances thestoragemodulus where its slope approaches zero towards lowfrequencies Nanofillers dispersed in each phase increase theviscosity of that phase but more importantly those located inthe interface of the two phases change the morphology of theblend by suppressing the coalescence of the blend as was seenby the downsizing effect in SEMmicrographsThiswill enablethe LDPESEBS-MA matrix to form a strong network withclay most likely due to the interaction of functional groupsof clay with the maleic anhydride groups grafted on thebackbones of SEBS-MA [27] Also due to the lower viscosityof SEBS-MA platelets andor tactoids of clay are more easilytransported localized and dispersed in the elastomer phaseThis improved degree of dispersion of clay helps forming astronger percolated network structure and showing such apronounced pseudosolid-like behavior [60ndash62]

34 AC Short-Term Breakdown Strength A two-parameterWeibull distribution was used to retrieve the dielectric break-down data of blends and nanocomposites via commercialsoftware Figure 7 exhibits the plots of AC short-term break-down strength of LDPEclay nanocomposites with differentthicknesses alongside with a column chart to compare theWeibull characteristic breakdown strengths (120572) which rep-resent the scale parameter of the Weibull distribution thatis the 632th percentile Scale and shape parameters togetherwith the 95 confidence intervals for each sample are listed inTable 2 FromFigure 7(a) it can be found that when having anaverage thickness of 140 120583m all nanocomposite samples showimproved breakdown strengthThe characteristic breakdownstrength for neat LDPE is 206 kVmmminus1 while it goes upupon addition of clay to 227 kVmmminus1 for 1 incorporation ofclay and to 248 kVmmminus1 when 25 of clay is incorporatedAt maximum improvement it reaches 266 kVmmminus1 fornanocomposite sample containing 5of clay showing almost30 improvement and then drops to 225 and 223 kVmmminus1for LDPE10C and LDPE15C samples respectively

Overall breakdown strength is enhanced at low nanoclayloadings up to 5 where it reaches the maximum but


LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15

160 180 200 220 240 260 280 300

AC breakdown strength (kVmm)

t asymp 140 m1

2

3

5

10

20

30405060708090

99Pr

obab

ility

of f

ailu

re (

)

(a)

LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15

160 180 200 220


t asymp 200 m

120 1401

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

(b)

LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15

t asymp 300 m

80 90 110 120100 140 150 160 170130


1

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

(c)

0 1 25 5 10 15Clay content ()

t sim 140 umt sim 200 umt sim 300 um

0

50

100

150

200

250

300Br

eakd

own

stren

gth

(KV

mm

)

(d)

Figure 7 Weibull probability plots of LDPEclay nanocomposites with different thicknesses (a) 140 120583m (b) 200 120583m and (c) 300 120583mComparison of the characteristic breakdown strength (d)

decreased beyond a certain value Consequently there is anoptimum loading of clay beyond which the enhancementis diminished A similar trend was seen in other works[63 64] Under AC condition the direction of the chargecarrier transportation keeps changing back and forth whichresults in local trapping and charge accumulation in theareas close to the electrodes Therefore the electric field isenhanced more between the interface of the electrodes andthe specimen where breakdown tends to initiate and prop-agate through the bulk This suggests that the improvementof AC breakdown strength upon incorporation of clay maybe originated from the delaying in the process of chargetransfer between electrodes through the material Layered

clay silicates despite having weak interfacial interaction withthe polymer matrix would postpone breakdown by creatinga tortuous path between and around themselves for chargecarriers to reach the opposite electrodes [65]

The influence of clay on improving the breakdownstrength of polymers has been widely discussed amongresearchers Zazoum et al [15] observed a consistentimprovement of dielectric breakdown strength on LLDPEupon addition of clay up to 20when 5clay is incorporatedThey related the improvement to the impact of the interfacebetween the polymer matrix and the nanoclay on the spacecharge distribution and charge densities They also explainedthe further improvement on sample having compatibilizer


Table2Weibu

llparametersfor

ACbreakd

owntestof

LDPE

claynano

compo

sites

Samplelowast

Thickn

esssim

140120583

mTh

ickn

esssim

200120583

mTh

ickn

esssim

300120583

m120572

(kVmmminus1)

12057395CI

120572

(kVmmminus1)

12057395CI

120572

(kVmmminus1)

12057395CI

Lower

Upp

erLo

wer

Upp

erLo

wer

Upp

erLD

PE206

2496

202

209

172

2556

169

175

137

1659

133

141

LDPE

1C227

2073

222

232

177

2126

173

180

146

1133

140

152

LDPE

25C

248

1826

242

255

185

1941

181

190

144

1143

139

150

LDPE

5C

266

1320

257

275

198

1575

192

204

145

1040

138

151

LDPE

10C

225

2210

220

230

169

1674

164

174

142

966

135

149

LDPE

15C

223

2270

218

227

167

1559

162

172

139

1123

133

145

lowastNum

bero

fspecimensis2

0fora

llsamples


to the possible change of microstructure Thelakkadan et al[66] suggested that clay layers act as scattering sites for thecharge carriers During the scattering the charges transfertheir energy to nanoparticles and lose momentum Howeverthe nanoparticles are closely packed and do not involve in thebreakdown process therefore it requires additional voltageThis also suggests that the highest improvement happenswhen nanoclay is in the exfoliated state

Liao et al [67] investigated the electrical properties ofLDPE composites containing various contents of montmo-rillonite They found out that the AC breakdown strengthincreased when 1 3 and 5 of MMT are incorporated withthe maximum improvement by 11 in case of 1 incorpora-tion of MMT Shah et al [68] witnessed a massive 60 and80 improvement in the dielectric breakdown strength ofhigh density polyethylene (HDPE) upon addition of 5 wtof unmodified and organomodified clay respectively Theyassumed that the exfoliated and intercalated clay plateletsdistribute the electric stress and increase the path lengthfor the breakdown They concluded that the modificationof clay with quaternary ammonium compound reduces thesurface energy of the clay platelets making the intercalationof polymer molecules more feasible

Moreover Ghosh et al [69] reported a remarkable 84improvement in the dielectric breakdown strength uponincorporation of only 02 wt unmodified nanoclay into apoly(vinylidene fluoride) (PVDF) matrix They observed alayer-by-layer structure of nanoclay within the PVDF matrixand hypothesized that the formation of the tortuous pathbetween the electrodes blocks the path of the applied electricfield and enhances the breakdown strengthThis barrier effecthas been shown to be maximumwhen the layers are orientedperpendicular to the field

Also the orientation of clay layer can add to the mag-nitude of the improvement Tomer et al [70] studied thealignment effect of nanoclay on electrical properties ofpolyethylene They reported that when 6 nanoclay is ran-domly distributed the characteristic DC breakdown strengthis not improved and the shape parameter is reduced from21 to7with respect to the originalmatrixHowever whennanoclayis oriented the breakdown strength increases by 23 and thereduction in shape parameter is negligible They hypothe-sized that the randomness acts as defect initiators promotingelectron tree inception whereas the orientation of fillerfrustrates the progress of electrical treeing by offering moretortuous paths to treeing and possessing larger populationsand more structured scattering centers In their recent workthey quantified the effect of orientation and confirmed thebarrier effect [71] Bulinski et al [72] challenged the type ofnanoclay and concluded that polypropylene nanocompositeshows higher breakdown strength when it is reinforced withsynthetic clay than with natural clay They stated that thisdiscrepancy goes to the degree of pureness and the slightlylower improvement for natural clay is due to the negativeeffects of the impurities

Studies on the influence of nanoparticles on the break-down strength of polymers have not been limited to clayA huge part of the recent works was dedicated to thepolymeric nanocomposites containing silica nanoparticles

The incorporation of nanosilica is widely reported to decreasethe AC and DC breakdown strength of polymers [73ndash80]However there are some reports indicating no change [81 82]or even improvement on the breakdown strength [83ndash85]Readers are referred to a review on the effects of additionof nanoreinforcements on dielectric breakdown properties ofpolymers that has been published by Li et al in 2010 [11]Later they published another review [17] with a comprehen-sive look into breakdown mechanism of nanocomposites

From Figure 7 it is also clear that when the thicknessof specimens increases the breakdown strength significantlydecreases For neat LDPE 120572 drops to 172 kVmmminus1 and137 kVmmminus1 for samples with 200120583m and 300 120583m thick-nesses respectively Nanocomposites also show reducedbreakdown strength to the point where no significantimprovement is detected with the thickest samples Thereduction of breakdown strength with sample thickness is ageneral trend for solid dielectrics It is often related to thegreater density of defectswithin thematerial [86] Breakdownis believed to initiate from defects where electrons cangain enough energy since the free path length in insulatingpolymers is short and cannot be easily destroyed by electronavalanche [87] These defects include preexisting disconti-nuities and defects generated while under electric field Thenumber of defects in the pathways of charge carriers ishigher in thicker sampleswhich facilitate the percolation pathdevelopment thus lowering the breakdown strength [88ndash90]

When modeling the breakdown mechanism researchershave incorporated the empirical thickness dependence usinga prefactor term in Lorentz relation firstly introduced byKlein and Gafni [91] However very recently McPherson[92] challenged this long-term belief He stated that thereduction in breakdown strength of dielectric towards higherthicknesses comes from the reduction in bond strength as aresult of higher electric field within the thicker dielectricsHe claimed that bond weakening leads to lower breakdownstrength in thicker dielectrics and is independent of actualbond-breakage mechanism

On higher loading of clay the reduction in breakdownstrength ismore pronouncedThis is because with increasingamount of clay chance of particle agglomeration increaseswhich adds to the defect density Electric field is enhancedaround these agglomerates and eventually advances thebreakdown [93ndash95] In samples with thickness of 200120583m(Figure 7(b)) this effect dominates the mechanism neutral-izes the improvement of clay and takes 120572 below the neatLDPE Here the saturation effect happens at 5 of clay abovewhich the breakdown strength is heavily diminished With300 120583m of thickness (Figure 7(c)) the general defect densityis large enough to solely dominate the breakdownmechanismand is independent of agglomeration effect of clay

According to Table 2 Weibull shape parameter (120573) ismaximum for neat LDPE for all series but significantlydecreases upon incorporation of clayThis ismost likely origi-nated from an evolution of the sensitivity of themeasurementto defects which speeds up the breakdown and increases theunreliabilityThis scattering probability is mostly determinedby the presence of clay tactoids boundaries as was evidencein SEM images and the possible agglomerates


LDPEMALDPEMA1C


t asymp 140 m1

2

3

5

10

20

30405060708090

99Pr

obab

ility

of f

ailu

re (

)

150 175 200 225 250 275 300

LDPEMA25C

LDPEMA5CLDPEMA10CLDPEMA15C

(a)


t asymp 140 m1

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

100 150 200 250 300

LDPELDPESEBSLDPESEBS5C


(b)

Figure 8 Weibull probability plots of LDPEMAclay nanocomposites (a) and LDPESEBS blends and nanocomposites (b)

Figure 8 exhibits the Weibull probability plots for ACbreakdown strength of a series of LDPEClay nanocompos-ites containing 5wtMA as compatibilizer (a) and blends ofLDPE and two types of SEBS along with their correspondingnanocomposites containing 5 of clay (b) Comparing tothe original LDPEClay nanocomposites here more or lessa similar trend in increasing the breakdown strength can beseen for samples containingMA Saturation happens at 5 ofclay and then reduces but still remains above the neat LDPEHowever the improvement is not significant as to comparewhen MA is not incorporated This means the addition ofMA compatibilizer was unnecessary and does not affect thebreakdown strength enhancement and yet diminishes it tosome degree

Regarding the AC breakdown strength of blends of LDPEwith SEBS elastomers (Figure 8(b)) a noticeable reduction isseen comparing to the neat LDPE 120572 is down to 199 kVmmminus1for LDPESEBS and to 198 kVmmminus1 for LDPESEBS-MAwhile 120573 is significantly reduced This can be explained bythe dilution effect as neat SEBS polymer generally possesseslower breakdown value than the neat LDPE and accordingto the rule of mixture for plastics LDPESEBS blend isexpected to have lower breakdown strength [96] The lowerbreakdown value for SEBS elastomer probably comes from itslower Youngrsquos modulus [97] where electromechanical tensilestrength generated orthogonal to the field during breakdownmode would induce more voids and crack propagation ina similar manner to that caused by mechanical stress [98]Upon addition of 5 clay the characteristic breakdownstrengths of blends significantly increase similar to the resultof original LDPEclay nanocomposite

35 DC Short-Term Breakdown Strength Figure 9 comparesthe DC breakdown strength of blends and nanocomposites ofLDPE Table 3 lists the statistical variables of the mentioned

Table 3 Weibull parameters for DC breakdown test of LDPEclayblends and nanocomposites

Sample Number ofspecimens

120572

(kVmmminus1) 120573

95confidenceintervals

Lower UpperLDPE 8 470 1987 453 478LDPE1C 8 387 1077 361 414LDPE25C 8 439 1123 412 469LDPE5C 8 366 933 338 396LDPE10C 8 337 954 312 364LDPE15C 8 294 1116 275 314LDPESEBS 8 386 1014 359 415LSPESEBS5C 8 276 702 248 306LDPESEBS-MA 8 385 1155 361 410

LDPESEBS-MA5C 8 309 709 279 343

plots One can see that the DC breakdown strength of neatLDPE is as high as 470 kVmm From Figure 9(a) it goesdown upon addition of clay for all the formulations and sinksto around 294 kVmm at highest amount of nanofiller TheDC breakdown strength decreases with increased loading ofclay The only comparable result is seen for 25 loading ofclay which shows a characteristic DC breakdown strength of439 kVmm Blends of LDPE with both types of SEBS alsoshow a noticeable 18 reduction in DC breakdown strengthwith having 120572 around 386 kVmm Further reductions areseen for the corresponding nanocomposites containing 5 ofclay


LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15

DC breakdown strength (kVmm)

t asymp 200 m

1

2

3

5

10

20

30405060708090

99Pr

obab

ility

of f

ailu

re (

)

200 250 350 400 450 500 550300

(a)


t asymp 200 m

1

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

150 200 400300 500



(b)

Figure 9 Weibull plots of LDPE nanocomposites reinforced with clay (a) and blends of LDPE and two types of SEBS along with theircorresponding nanocomposites containing 5 of clay

Unlike the AC breakdown strength the DC breakdowntrend is completely different It is strongly sensitive to thetype of matrix and the amount of nanofiller and in allcases the DC breakdown strength is lower than that ofneat LDPE This behavior is not strange and has beenreported before [93 99ndash101]The reduction inDCbreakdownstrength could be originated from several parameters and itis beyond the agglomeration effect of nanofiller which wasthe primary reason for reduction in AC breakdown strengthNevertheless the particle agglomeration still remains as asimple explanation and its effect might be more pronouncedonDCbreakdown strength due to the higher required voltagefor breakdown

The increased charge trapping as a result of the intro-duction of clay can also contribute to the reduction of DCbreakdown strength in nanocomposites Charges can becomestationary in trap sites around the nanoparticle also knownas space charge effect This will increase the field inside thematerial and advance the breakdown Space charge is not anissue for AC systems where the oscillating polarity reversaldoes not allow sufficient time for charge to be trapped Thepoor dispersion of clay tactoids also adds to the magnitudeof charge trapping and the breakdown strength goes to loweramount with increasing in clay loading Thermal breakdownis another possible process of DC breakdown for LDPE[102] which under DC supply can be affected largely by theelectrical conductivity As the voltage goes up much morebefore breakdown comparing to AC test it is possible thatthermal instability of the material advances the breakdown

4 Conclusion

In this study dielectric breakdown properties of clay-basedLDPE nanocomposites have been investigated as one of the

most important parameters to evaluate the potentials toreplace the current HV cable insulating materials Clay layershave been shown to be widely dispersed and distributed inLDPE matrix especially when a compatibilizer is utilized Asa result a remarkable improvement on the AC breakdownstrength of the nanocomposites has been achieved Thiswas maximized when 5 of clay was incorporated whilethe degree of improvements in lower amount of clay isstill significant It suggests that organomodified clay hasthe potentials to make electrical properties of LDPE matrixcomparable to currently used XLPE-type cable insulationmaterials considering its easy access and cheap price

The use of immiscible blends of LDPE with two typesof SEBS copolymer also showed interesting results uponaddition of clay It was witnessed that clay can alter themorphology of the blend when it is firstly mixed withthe polyethylene through the migration process into theelastomer phase and results in higherACbreakdown strengthcomparing to the unfilled blends Considering the provenmechanical flexibility of SEBS copolymer this type of blendsdoes have the potentials to be used as insulating materials inHV applications

Conflicts of Interest

The authors declare that there are no conflicts of interestregarding the publication of this paper

Acknowledgments

The authors acknowledge the sincere cooperation of thestaff of the Laboratory of Innovation Technologies (LIT) atUniversity of Bologna especially Dr Fabrizio Palmieri


References

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and dielectric breakdown in polymeric dielectricsrdquo IEEE Trans-actions on Dielectrics and Electrical Insulation vol 19 no 3 pp200ndash204 1984

[3] T Tanaka ldquoDielectric breakdown in polymer nanocompositesrdquoin Polymer Nanocomposites pp 113ndash137 Springer 2016

[4] L A Dissado and J C Fothergill Electrical Degradation andBreakdown in Polymers vol 9 IET 1992

[5] A R Blythe and D Bloor Electrical Properties of PolymersCambridge University Press 2005

[6] V A Zakrevskii N T Sudar A Zaopo and Y A DubitskyldquoMechanism of electrical degradation and breakdown of insu-lating polymersrdquo Journal of Applied Physics vol 93 no 4 pp2135ndash2139 2003

[7] A K Jonscher and R Lacoste ldquoOn a cumulative model ofdielectric breakdown in solidsrdquo IEEETransactions onDielectricsand Electrical Insulation vol 19 no 6 pp 567ndash577 1984

[8] Z Wang T Iizuka M Kozako Y Ohki and T TanakaldquoDevelopment of epoxyBN composites with high thermalconductivity and sufficient dielectric breakdown strength partII-breakdown strengthrdquo IEEE Transactions on Dielectrics andElectrical Insulation vol 18 no 6 pp 1973ndash1983 2011

[9] Y Cao P C Irwin and K Younsi ldquoThe future of nanodi-electrics in the electrical power industryrdquo IEEE Transactions onDielectrics and Electrical Insulation vol 11 no 5 pp 797ndash8072004

[10] T J Lewis ldquoNanometric dielectricsrdquo IEEE Transactions onDielectrics and Electrical Insulation vol 1 no 5 pp 812ndash8251994

[11] S Li G Yin G Chen et al ldquoShort-term breakdown and long-term failure in nanodielectrics A reviewrdquo IEEE Transactions onDielectrics and Electrical Insulation vol 17 no 5 pp 1523ndash15352010

[12] M Roy J K Nelson R KMacCrone L S Schadler CW Reedand R Keefe ldquoPolymer nanocomposite dielectrics-the role ofthe interfacerdquo IEEE Transactions on Dielectrics and ElectricalInsulation vol 12 no 4 pp 629ndash643 2005

[13] J K Nelson J C Fothergill L A Dissado and W PeasgoodldquoTowards an understanding of nanometric dielectricsrdquo in Pro-ceedings of the IEEE Annual Report Conference on ElectricalInsulation and Dielectric Phenomena pp 295ndash298 October2002

[14] D Fabiani P Mancinelli C Vanga-Bouanga M F Frechetteand J Castellon ldquoEffect of graphene-oxide content on spacecharge characteristics of PE-basednanocompositesrdquo inProceed-ings of the 34th IEEE Electrical Insulation Conference (EIC rsquo16)pp 631ndash634 IEEE June 2016

[15] B Zazoum E David and A D Ngo ldquoCorrelation betweenstructure and dielectric breakdown in LDPEHDPEclaynanocompositesrdquo ISRN Nanomaterials vol 2014 Article ID612154 9 pages 2014

[16] T J Lewis ldquoInterfaces are the dominant feature of dielectricsat the nanometric levelrdquo IEEE Transactions on Dielectrics andElectrical Insulation vol 11 no 5 pp 739ndash753 2004

[17] S Li L Yang W Liu and W Wang Dielectric Breakdown ofPolymer Nanocomposites 2016

[18] W Peng X Huang J Yu P Jiang and W Liu ldquoElectricaland thermophysical properties of epoxyaluminum nitride

nanocomposites Effects of nanoparticle surface modificationrdquoComposites Part A Applied Science and Manufacturing vol 41no 9 pp 1201ndash1209 2010

[19] X Huang C Kim P Jiang Y Yin and Z Li ldquoInfluence of alu-minum nanoparticle surface treatment on the electrical prop-erties of polyethylene compositesrdquo Journal of Applied Physicsvol 105 no 1 Article ID 014105 2009

[20] L M Robeson Polymer Blends Hanser Munchen Germany2007

[21] MM Coleman P C Painter and J F Graf Specific Interactionsand the Miscibility of Polymer Blends CRC Press 1995

[22] P Potschke and D R Paul ldquoFormation of co-continuous struc-tures in melt-mixed immiscible polymer blendsrdquo Journal ofMacromolecular Science Part C Polymer Reviews vol 43 no1 pp 87ndash141 2003

[23] G Filippone N T Dintcheva F P La Mantia and D AciernoldquoSelective localization of organoclay and effects on the mor-phology and mechanical properties of LDPEPA11 blends withdistributed and co-continuousmorphologyrdquo Journal of PolymerScience Part B Polymer Physics vol 48 no 5 pp 600ndash609 2010

[24] G P Kar S Biswas R Rohini and S Bose ldquoTailoring thedispersion of multiwall carbon nanotubes in co-continuousPVDFABS blends to design materials with enhanced electro-magnetic interference shieldingrdquo Journal ofMaterials ChemistryA vol 3 no 15 pp 7974ndash7985 2015

[25] S P Pawar and S Bose ldquoPeculiar morphological transitionsinduced by nanoparticles in polymeric blends Retarded relax-ation or altered interfacial tensionrdquo Physical Chemistry Chem-ical Physics vol 17 no 22 pp 14470ndash14473 2015

[26] S Pavlidou and C D Papaspyrides ldquoA review on polymermdashlayered silicate nanocompositesrdquo Progress in Polymer Sciencevol 33 no 12 pp 1119ndash1198 2008

[27] E Helal N R Demarquette E David and M Frechette ldquoEval-uation of dielectric behavior of polyethylenethermoplasticelastomer blends containing zinc oxide (ZnO) nanoparticles forhigh voltage insulationrdquo in Proceedings of the 34th IEEE Elec-trical Insulation Conference (EIC rsquo16) pp 592ndash595 IEEE June2016

[28] M Alexandre and P Dubois ldquoPolymer-layered silicate nano-composites preparation properties and uses of a new class ofmaterialsrdquoMaterials Science and Engineering R Reports vol 28no 1 pp 1ndash63 2000

[29] M Eesaee and A Shojaei ldquoEffect of nanoclays on the mechan-ical properties and durability of novolac phenolic resinwovenglass fiber composite at various chemical environmentsrdquo Com-posites Part A Applied Science and Manufacturing vol 63 pp149ndash158 2014

[30] M-J Dumont A Reyna-Valencia J-P Emond and MBousmina ldquoBarrier properties of polypropyleneorganoclaynanocompositesrdquo Journal of Applied Polymer Science vol 103no 1 pp 618ndash625 2007

[31] J Tokarsky L Kulhankova L Neuwirthova et al ldquoHighlyanisotropic conductivity of tablets pressed from polyaniline-montmorillonite nanocompositerdquo Materials Research Bulletinvol 75 pp 139ndash143 2016

[32] L Asrsquohabi S H Jafari B Baghaei H A Khonakdar PPotschke and F Bohme ldquoStructural analysis of multicom-ponent nanoclay-containing polymer blends through simplemodel systemsrdquo Polymer Journal vol 49 no 8 pp 2119ndash21262008

[33] L Li W Yong X Fangming Y Li H Liang and Z ZuowanldquoEffects of functionalized multiwalled carbon nanotubes on the


morphologies and mechanical properties of PPEVA blendrdquoJournal of Polymer Science Part B Polymer Physics vol 47 no15 pp 1481ndash1491 2009

[34] S S Ray S Pouliot M Bousmina and L A Utracki ldquoRoleof organically modified layered silicate as an active interfa-cial modifier in immiscible polystyrenepolypropylene blendsrdquoPolymer vol 45 no 25 pp 8403ndash8413 2004

[35] M Si T Araki H Ader et al ldquoCompatibilizing bulk polymerblends by using organoclaysrdquo Macromolecules vol 39 no 14pp 4793ndash4801 2006

[36] Z Fang Y Xu and L Tong ldquoEffect of clay on the morphologyof binary blends of polyamide 6 with high density polyethyleneand HDPE-graft-acrylic acidrdquo Polymer Engineering amp Sciencevol 47 no 5 pp 551ndash559 2007

[37] LMinkovaH Yordanov S Filippi andNGrizzuti ldquoInterfacialtension of compatibilized blends of LDPE andPA6 the breakingthread methodrdquo Polymer vol 44 no 26 pp 7925ndash7932 2003

[38] E Helal N R Demarquette L G Amurin E David DJ Carastan and M Frechette ldquoStyrenic block copolymer-based nanocomposites implications of nanostructuration andnanofiller tailored dispersion on the dielectric propertiesrdquoPolymer vol 64 pp 139ndash152 2015

[39] S Asai K Sakata M Sumita and K Miyasaka ldquoEffect ofinterfacial free energy on the heterogeneous distribution ofoxidized carbon black in polymer blendsrdquo Polymer Journal vol24 no 5 pp 415ndash420 1992

[40] M Sumita K Sakata S Asai K Miyasaka and H NakagawaldquoDispersion of fillers and the electrical conductivity of polymerblends filled with carbon blackrdquo Polymer Bulletin vol 25 no 2pp 265ndash271 1991

[41] A L Persson and H Bertilsson ldquoViscosity difference as dis-tributing factor in selective absorption of aluminium boratewhiskers in immiscible polymer blendsrdquo Polymer Journal vol39 no 23 pp 5633ndash5642 1998

[42] A E Zaikin R R Karimov and V P Arkhireev ldquoA study ofthe redistribution conditions of carbon black particles from thebulk to the interface in heterogeneous polymer blendsrdquo ColloidJournal vol 63 no 1 pp 53ndash59 2001

[43] A E Zaikin E A Zharinova and R S Bikmullin ldquoSpecifics oflocalization of carbon black at the interface between polymericphasesrdquo Polymer Science Series A vol 49 no 3 pp 328ndash3362007

[44] L Elias F Fenouillot J CMajeste andPCassagnau ldquoMorphol-ogy and rheology of immiscible polymer blends filledwith silicananoparticlesrdquo Polymer vol 48 no 20 pp 6029ndash6040 2007

[45] L Elias F Fenouillot J C Majeste P Alcouffe and P Cas-sagnau ldquoImmiscible polymer blends stabilized with nano-silicaparticles rheology and effective interfacial tensionrdquo Polymervol 49 no 20 pp 4378ndash4385 2008

[46] E Helal E David M Frechette and N R Demarquette ldquoTher-moplastic elastomer nanocomposites with controlled nanopar-ticles dispersion forHV insulation systems correlation betweenrheological thermal electrical and dielectric propertiesrdquo Euro-pean Polymer Journal vol 94 pp 68ndash86 2017

[47] P Cassagnau ldquoMelt rheology of organoclay and fumed silicananocompositesrdquo Polymer vol 49 no 9 pp 2183ndash2196 2008

[48] Y Song andQ Zheng ldquoLinear rheology of nanofilled polymersrdquoJournal of Rheology vol 59 no 1 pp 155ndash191 2015

[49] S Bagheri-Kazemabad D Fox Y Chen et al ldquoMorphol-ogy rheology and mechanical properties of polypropyleneethylene-octene copolymerclay nanocomposites Effects of the

compatibilizerrdquo Composites Science and Technology vol 72 no14 pp 1697ndash1704 2012

[50] J Ren A S Silva and R Krishnamoorti ldquoLinear viscoelasticityof disordered polystyrene-polyisoprene block copolymer basedlayered-silicate nanocompositesrdquo Macromolecules vol 33 no10 pp 3739ndash3746 2000

[51] G Gong J Wu Y Lin C Chan and M Yang ldquoDynamic rhe-ological behavior of isotactic polypropylene filled with nano-calcium carbonate modified by stearic acid coatingrdquo Journal ofMacromolecular Science Part B Physics vol 48 no 2 pp 329ndash343 2009

[52] D Wu L Wu M Zhang and Y Zhao ldquoViscoelasticity andthermal stability of polylactide composites with various func-tionalized carbon nanotubesrdquo Polymer Degradation and Stabil-ity vol 93 no 8 pp 1577ndash1584 2008

[53] W D Lee S S Im H-M Lim and K-J Kim ldquoPrepara-tion and properties of layered double hydroxidepoly(ethyleneterephthalate) nanocomposites by direct melt compoundingrdquoPolymer vol 47 no 4 pp 1364ndash1371 2006

[54] G Romeo G Filippone A Fernandez-Nieves P Russo andD Acierno ldquoElasticity and dynamics of particle gels in non-Newtonian meltsrdquo Rheologica Acta vol 47 no 9 pp 989ndash9972008

[55] A S Sarvestani ldquoModeling the solid-like behavior of entangledpolymer nanocomposites at low frequency regimesrdquo EuropeanPolymer Journal vol 44 no 2 pp 263ndash269 2008

[56] N Hasegawa and A Usuki ldquoSilicate layer exfoliation inpolyolefinclay nanocomposites based on maleic anhydridemodified polyolefins and organophilic clayrdquo Journal of AppliedPolymer Science vol 93 no 1 pp 464ndash470 2004

[57] M-T Ton-That F Perrin-Sarazin K C Cole M N Bureauand J Denault ldquoPolyolefin nanocomposites formulation anddevelopmentrdquo Polymer Engineering amp Science vol 44 no 7 pp1212ndash1219 2004

[58] D J Carastan N R Demarquette A Vermogen and KMasenelli-Varlot ldquoLinear viscoelasticity of styrenic block copol-ymersmdashclay nanocompositesrdquo Rheologica Acta vol 47 no 5-6pp 521ndash536 2008

[59] HVeenstra P C J Verkooijen B J J VanLent J VanDamA PDe Boer andA PH J Nijhof ldquoOn themechanical properties ofco-continuous polymer blends Experimental and modellingrdquoPolymer Journal vol 41 no 5 pp 1817ndash1826 2000

[60] B B Khatua D J Lee H Y Kim and J K Kim ldquoEffect of organ-oclay platelets on morphology of nylon-6 and poly(ethylene-ran-propylene) rubber blendsrdquo Macromolecules vol 37 no 7pp 2454ndash2459 2004

[61] W S Chow A Abu Bakar Z A Mohd Ishak J Karger-Kocsis and U S Ishiaku ldquoEffect of maleic anhydride-graftedethylene-propylene rubber on the mechanical rheological andmorphological properties of organoclay reinforced polyamide6polypropylene nanocompositesrdquo European Polymer Journalvol 41 no 4 pp 687ndash696 2005

[62] R R Tiwari D L Hunter and D R Paul ldquoExtruder-madeTPO nanocomposites I Effect of maleated polypropylene andorganoclay ratio on the morphology and mechanical proper-tiesrdquo Journal of Polymer Science Part B Polymer Physics vol 50no 22 pp 1577ndash1588 2012

[63] S Li G Yin and J Li ldquoBreakdown performance of low densitypolyethylene nanocompositesrdquo in Proceedings of the IEEE 10thInternational Conference on the Properties and Applications ofDielectric Materials (ICPADM rsquo12) IEEE July 2012


[64] S Li G Yin S Bai and J Li ldquoA new potential barrier model inepoxy resin nanodielectricsrdquo IEEE Transactions on Dielectricsand Electrical Insulation vol 18 no 5 pp 1535ndash1543 2011

[65] S P Fillery H Koerner L Drummy et al ldquoNanolaminatesincreasing dielectric breakdown strength of compositesrdquo ACSApplied Materials amp Interfaces vol 4 no 3 pp 1388ndash1396 2012

[66] A SThelakkadan G Coletti F Guastavino andA Fina ldquoEffectof the nature of clay on the thermo-mechanodynamical andelectrical properties of epoxyclay nanocompositesrdquo PolymerComposites vol 32 no 10 pp 1499ndash1504 2011

[67] R Liao G Bai L Yang H Cheng Y Yuan and J GuanldquoImproved electric strength and space charge characterizationin LDPE composites with montmorillonite fillersrdquo Journal ofNanomaterials vol 2013 Article ID 712543 7 pages 2013

[68] K S Shah R C Jain V Shrinet A K Singh and D PBharambe ldquoHigh density polyethylene (HDPE) clay nano-composite for dielectric applicationsrdquo IEEE Transactions onDielectrics and Electrical Insulation vol 16 no 3 pp 853ndash8612009

[69] S K Ghosh W Rahman T R Middya S Sen and D MandalldquoImproved breakdown strength and electrical energy storageperformance of 120574-poly(vinylidene fluoride)unmodified mont-morillonite clay nano-dielectricsrdquo Nanotechnology vol 27 no21 Article ID 215401 2016

[70] V Tomer G Polizos C A Randall and E Manias ldquoPolyethy-lene nanocomposite dielectrics Implications of nanofiller ori-entation on high field properties and energy storagerdquo Journal ofApplied Physics vol 109 no 7 Article ID 074113 2011

[71] B Li C I Camilli P I Xidas K S Triantafyllidis andE Manias ldquoStructured polyethylene nanocomposites effectsof crystal orientation and nanofiller alignment on high fielddielectric propertiesrdquoMRS Advances vol 2 no 6 pp 363ndash3682017

[72] A Bulinski S S Bamji M Abou-Dakka and Y Chen ldquoDielec-tric properties of polypropylene containing synthetic and nat-ural organoclaysrdquo in Proceedings of the IEEE InternationalSymposium on Electrical Insulation (ISEI rsquo10) IEEE June 2010

[73] K Y Lau M A M Piah and K Y Ching ldquoCorrelating thebreakdown strength with electric field analysis for polyethy-lenesilica nanocompositesrdquo Journal of Electrostatics vol 86 pp1ndash11 2017

[74] T Krentz M M Khani M Bell et al ldquoMorphologicallydependent alternating-current and direct-current breakdownstrength in silicandashpolypropylene nanocompositesrdquo Journal ofApplied Polymer Science vol 134 no 1 Article ID 44347 2017

[75] P Luo S Wang B Feng Q Mu M Xu and Y Xu ldquoAC break-down strength and glass transition temperature of mesoporoussilicaEP compositerdquo in Proceedings of the 5th IEEE Interna-tional Conference on High Voltage Engineering and Application(ICHVE rsquo16) IEEE September 2016

[76] M Ritamaki I Rytoluoto M Niittymaki K Lahti and MKarttunen ldquoDifferences in AC and DC large-area breakdownbehavior of polymer thin filmsrdquo in Proceedings of the 1st IEEEInternational Conference on Dielectrics (ICD rsquo16) pp 1011ndash1014IEEE July 2016

[77] I L Hosier M Praeger A F Holt A S Vaughan and SG Swingler ldquoOn the effect of functionalizer chain lengthand water content in polyethylenesilica nanocomposites partImdashdielectric properties and breakdown strengthrdquo IEEE Trans-actions on Dielectrics and Electrical Insulation vol 24 no 3 pp1698ndash1707 2017

[78] K Lau A Vaughan G Chen I Hosier A Holt and KChing ldquoOn the space charge and DC breakdown behaviorof polyethylenesilica nanocompositesrdquo IEEE Transactions onDielectrics and Electrical Insulation vol 21 no 1 pp 340ndash3512014

[79] I L Hosier M Praeger A F Holt A S Vaughan and S GSwingler ldquoEffect of water absorption on dielectric propertiesof nano-silicapolyethylene compositesrdquo in Proceedings of theIEEE Conference on Electrical Insulation and Dielectric Phenom-ena (CEIDP rsquo14) pp 651ndash654 IEEE October 2014

[80] X Huang F Liu and P Jiang ldquoEffect of nanoparticle surfacetreatment onmorphology electrical and water treeing behaviorof LLDPE compositesrdquo IEEE Transactions on Dielectrics andElectrical Insulation vol 17 no 6 pp 1697ndash1704 2010

[81] T Tanaka ldquoDielectric nanocomposites with insulating proper-tiesrdquo IEEE Transactions on Dielectrics and Electrical Insulationvol 12 no 5 pp 914ndash928 2005

[82] G Iyer R S Gorur R Richert A Krivda and L E SchmidtldquoDielectric properties of epoxy based nanocomposites forhigh voltage insulationrdquo IEEE Transactions on Dielectrics andElectrical Insulation vol 18 no 3 pp 659ndash666 2011

[83] L Hui L S Schadler and J K Nelson ldquoThe influence ofmoisture on the electrical properties of crosslinked polyethy-lenesilica nanocompositesrdquo IEEE Transactions on Dielectricsand Electrical Insulation vol 20 no 2 pp 641ndash653 2013

[84] M Takala H Ranta P Nevalainen et al ldquoDielectric prop-erties and partial discharge endurance of polypropylene-silicananocompositerdquo IEEE Transactions on Dielectrics and ElectricalInsulation vol 17 no 4 pp 1259ndash1267 2010

[85] M Roy J K Nelson R K MacCrone and L S Schadler ldquoCan-didate mechanisms controlling the electrical characteristics ofsilicaXLPE nanodielectricsrdquo Journal of Materials Science vol42 no 11 pp 3789ndash3799 2007

[86] G Chen J Zhao S Li and L Zhong ldquoOrigin of thicknessdependent dc electrical breakdown in dielectricsrdquo AppliedPhysics Letters vol 100 no 22 Article ID 222904 2012

[87] K Theodosiou I Vitellas I Gialas and D P Agoris ldquoPolymerfilms degradation and breakdown in high voltage AC fieldsrdquoJournal of Electrical Engineering vol 55 no 9-10 pp 225ndash2312004

[88] H K Kim and F G Shi ldquoThickness dependent dielectricstrength of a low-permittivity dielectric filmrdquo IEEETransactionsonDielectrics and Electrical Insulation vol 8 no 2 pp 248ndash2522001

[89] R Degraeve G Groeseneken R Bellens et al ldquoNew insights inthe relation between electron trap generation and the statisticalproperties of oxide breakdownrdquo IEEE Transactions on ElectronDevices vol 45 no 4 pp 904ndash911 1998

[90] J Sune D Jimenez and E Miranda ldquoBreakdown modes andbreakdown statistics of ultrathin SiO

2gate oxidesrdquo International

Journal of High Speed Electronics and Systems vol 11 no 3 pp789ndash848 2001

[91] N Klein and H Gafni ldquoThe maximum dielectric strength ofthin silicon oxide filmsrdquo IEEE Transactions on Electron Devicesvol 13 no 2 pp 281ndash289 1966

[92] J W McPherson ldquoOn why dielectric breakdown strengthreduces with dielectric thicknessrdquo in Proceedings of the IEEEInternational Reliability Physics Symposium (IRPS rsquo16) IEEEApril 2016

[93] K Y Lau A S Vaughan G Chen and I L Hosier ldquoPolyethy-lene nanodielectrics the effect of nanosilica and its surface


treatment on electrical breakdown strengthrdquo in Proceedingsof the IEEE Conference on Electrical Insulation and DielectricPhenomena (CEIDP rsquo12) pp 21ndash24 IEEE October 2012

[94] A S Vaughan S G Swingler and Y Zhang ldquoPolyethylene nan-odielectrics The influence of nanoclays on structure formationand dielectric breakdownrdquo IEEJ Transactions on Fundamentalsand Materials vol 126 no 11 pp 1057ndash1063 2006

[95] J K Nelson and J C Fothergill ldquoInternal charge behaviour ofnanocompositesrdquo Nanotechnology vol 15 no 5 pp 586ndash5952004

[96] R J Crawford Plastics Engineering Butterworth-Heinemann1998

[97] M Kollosche and G Kofod ldquoElectrical failure in blends ofchemically identical soft thermoplastic elastomers with differ-ent elastic stiffnessrdquoApplied Physics Letters vol 96 no 7 ArticleID 071904 2010

[98] J P Jones J P Llewellyn and T J Lewis ldquoThe contributionof field-induced morphological change to the electrical agingand breakdown of polyethylenerdquo IEEE Electrical Insulation andDielectric Phenomena vol 12 no 5 pp 951ndash966 2005

[99] D Ma T A Hugener R W Siegel et al ldquoInfluence ofnanoparticle surface modification on the electrical behaviourof polyethylene nanocompositesrdquo Nanotechnology vol 16 no6 pp 724ndash731 2005

[100] X Y Huang Z S Ma Y Q Wang P K Jiang Y Yin andZ Li ldquoPolyethylenealuminum nanocomposites improvementof dielectric strength by nanoparticle surface modificationrdquoJournal of Applied Polymer Science vol 113 no 6 pp 3577ndash35842009

[101] Y Yin X Dong Z Li and X Li ldquoThe effect of electricallyprestressing on DC breakdown strength in the nanocompositeof low-density polyethylenenano-SiOxrdquo in Proceedings of theInternational Conference on Solid Dielectrics (ICSD rsquo07) pp372ndash376 IEEE July 2007

[102] M Nagao T Kimura Y Mizuno M Kosaki and M IedaldquoDetection of Joule heating before dielectric breakdown inpolyethylene filmsrdquo IEEE Transactions on Dielectrics and Elec-trical Insulation vol 25 no 4 pp 715ndash722 1990

CorrosionInternational Journal of

Hindawiwwwhindawicom Volume 2018

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The Scientific World Journal

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TribologyAdvances in



ChemistryAdvances in


Advances inPhysical Chemistry


BioMed Research InternationalMaterials

Journal of


Na

nom

ate

ria

ls


Journal ofNanomaterials

Submit your manuscripts atwwwhindawicom


inclusion as fillers (composites) Despite improvements inmechanical and thermal properties micro inclusions arebelieved to decrease the breakdown strength of polymers asthey may act as defects [8] Consequently nanofiller inclu-sions have been introduced recently to overcome the negativeeffects [3 9] thus creating a new area of materials callednanometric dielectrics or nanodielectrics [10] Nanoparticleswhich may be chemically modified with different approachesin order to have polar or nonpolar functional groups ontheir surface have shown very promising results [11] It iswell known that they have a great influence on breakdownproperties of polymers especially by the change in mor-phology of the semicrystalline polymers [12] They reducethe internal field [13] and alter the space charge distributionwithin the polymer matrix [14] Furthermore the interfacebetween polymer and nanoparticle plays a crucial role in thedielectric breakdown performance [15 16]The final obtainedmorphology and the physical and chemical characteristicsof the interface are greatly influenced by the dispersion andlocalization of nanoparticles and the nature of both phaseswhich will eventually influence the breakdown process bychanging the microscale aspects that is traps free volumeand carrier mobility [17] Therefore considerable attentionsmust be paid to tailor the interface with proper physical andchemical methods to obtain improved dielectric breakdownproperties [18 19]

Another well-established approach to develop new mate-rials is polymer blending [20] Since usually polymers havelow mixing entropy most polymer pairs tend to make animmiscible blend [21] During the mixing process and atrest the dynamic interplay between rheological phenomenadetermines the final morphology of the blend When havingdifferent mixing proportion the minor component tends todistribute all over the major phase as droplets Howeverin a narrow range of composition with proper processingthe blend microstructure can turn into cocontinuous distin-guished by amutual interpenetration of the two componentsThis type of microstructure is well-known for its tunable andsubstantial combination of functional and structural proper-ties but is hard to achieve [22] It has been well-establishedthat nanoparticles can be adopted to stabilize themorphologyof immiscible blends [23ndash25] However this approach has notbeen fully employed to discover the potential improvementsin electrical breakdown properties of polymers

In this paper attempts to evaluate the short-term AC andDC electrical breakdown properties for clay-based nanocom-posites of low-density polyethylene (LDPE) have been pre-sented alongside with observation of the morphology ofthose materials Also the possibility of using a binary blendto achieve a tailored dispersion of nanoclays to result in animproved AC and DC electrical breakdown was evaluated

2 Experimental

21 Materials and Processing Commercially available pre-mixed LDPEclay masterbatch (nanoMax-LDPE) contain-ing 50 organomodified montmorillonite (O-MMT) wassupplied from Nanocor and used as the source of the nanor-einforcement The masterbatch was further diluted with

low-density polyethylene (LDPE) supplied from Marplexin powder form with a density of 0922 gcm3 and MFI of09 g10min (190∘C216 kg) to the desired concentrations ofclay Maleic anhydride grafted linear low-density polyethy-lene (LLDPE-g-MA) was supplied from DuPont (FusabondM603) and has been used as a compatibilizer It has a densityof 0940 gcm3 and MFI of 25 gmin and is being referred toasMA in thismanuscript Two series of nanocomposites wereprepared with and without 5wt of the compatibilizer withconcentration profile of clay being set as 1 25 5 10 and 15

The same procedure was used to prepare blends andnanocomposites of LDPE with two grades of polystyrene-b-poly(ethylene-co-butylene)-b-polystyrene (SEBS) thermo-plastic elastomer supplied from Kraton G1652 and FG1901The former with a MFI of 5 (230∘C216 kg) based on ASTMD1238 (as declared by the supplier) is referred to as SEBS inthis manuscript The latter with a MFI of 22 which contains14ndash2wt of maleic anhydride (MA) is referred to as SEBS-MA Both grades contain 30wt fractions of polystyrene(PS) block in their structure and have a density of 091 gcm3

Melt compounding via extrusion process has been per-formed using a corotating twin-screw extruder All materialswere dried prior to extrusion in a vacuum oven at 45∘C forat least 36 h andmanually premixed A temperature profile of145ndash170∘C was set from hopper to die The pellets obtainedwere press-molded using an electrically heated hydraulicpress into thin plates with various thicknesses regarding thefuture characterization Samples were first preheated for 5minutes and then hot-pressed at 155∘C (165∘C for blends) foranother 5 minutes under the pressure of 10MPa Press platesthen were water-cooled with a rate of 10∘C per minute tothe ambient temperature Table 1 represents a summary ofthe composition of the final blends and nanocomposites Incase of blends the mass fractions of the two phases are setequal Note that the nominal percentages of clay have beenused since the thermogravimetric analysis (TGA) showed(not shown here) that the actual weight percentage of clay inthe masterbatch is 32wt

22 Characterization The morphology of the as-obtainednanocomposites was characterized by high resolution scan-ning electron microscopy (SEM) using a Hitachi SU-8230Field Emission-STEM microscope Samples were cryogeni-cally cut and sputtered with a 20 nm layer of platinum usinga Turbo-Pumped Sputter Coater (Q150T S) prior to theobservation Solvent extraction has been used to investigatethe microscopic structure of the blends Some samples wereheld in Toluene for 24 h while being gently stirred at roomtemperature and then washed with alcohol before SEMobservation

Transmission Electron Microscopy has been also con-ducted With respect to SEM it employs electron beaminstead of light beam It has been done using a FEI TecnaiG2F20 STEM operated at 200 kV The device is equippedwith a Gatan Ultrascan 4000 4k times 4k CCD Camera System(Model 895) Samples were cryogenically cut to create thinlayers that allow electron beam penetration The point-to-point and line resolutions of the TEM are respectively024 nm and 017 nm




Sample

HV AC

Surrounding medium

Electrodes

4m

m

(a)

HV DC

60mm

30mm

7m

m(b)



001) as

2119889 sin 120579 = 120582 (1)









Inte

nsity

(au

)



2 3 4 5 6 7 8 9 10 1112 (degree)

X-raysource

(a)



Inte

nsity

(au

)

2 3 4 5 6 7 8 9 10 1112 (degree)

X-raysource

(b)




001) while





(a)

(b)









(a) (b)

(c) (d)

(e) (f)

(g) (h)










SEBSLDPEClay






LDPESEBSLDPESEBS5C

1E + 02

1E + 03

1E + 04

1E + 05

1E + 06

Stor

age m

odul

us (P

a)










LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15

160 180 200 220 240 260 280 300


t asymp 140 m1

2

3

5

10

20

30405060708090

99Pr

obab

ility

of f

ailu

re (

)

(a)

LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15

160 180 200 220


t asymp 200 m

120 1401

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

(b)

LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15

t asymp 300 m

80 90 110 120100 140 150 160 170130


1

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

(c)

0 1 25 5 10 15Clay content ()


0

50

100

150

200

250

300Br

eakd

own

stren

gth

(KV

mm

)

(d)






Table2Weibu

llparametersfor

ACbreakd

owntestof

LDPE

claynano

compo

sites

Samplelowast

Thickn

esssim

140120583

mTh

ickn

esssim

200120583

mTh

ickn

esssim

300120583

m120572

(kVmmminus1)

12057395CI

120572

(kVmmminus1)

12057395CI

120572

(kVmmminus1)

12057395CI

Lower

Upp

erLo

wer

Upp

erLo

wer

Upp

erLD

PE206

2496

202

209

172

2556

169

175

137

1659

133

141

LDPE

1C227

2073

222

232

177

2126

173

180

146

1133

140

152

LDPE

25C

248

1826

242

255

185

1941

181

190

144

1143

139

150

LDPE

5C

266

1320

257

275

198

1575

192

204

145

1040

138

151

LDPE

10C

225

2210

220

230

169

1674

164

174

142

966

135

149

LDPE

15C

223

2270

218

227

167

1559

162

172

139

1123

133

145

lowastNum

bero

fspecimensis2

0fora

llsamples













LDPEMALDPEMA1C


t asymp 140 m1

2

3

5

10

20

30405060708090

99Pr

obab

ility

of f

ailu

re (

)

150 175 200 225 250 275 300

LDPEMA25C


(a)


t asymp 140 m1

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

100 150 200 250 300



(b)







120572

(kVmmminus1) 120573



LDPESEBS-MA5C 8 309 709 279 343



LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15


t asymp 200 m

1

2

3

5

10

20

30405060708090

99Pr

obab

ility

of f

ailu

re (

)

200 250 350 400 450 500 550300

(a)


t asymp 200 m

1

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

150 200 400300 500



(b)




4 Conclusion






Acknowledgments



References


















































































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls







Sample

HV AC

Surrounding medium

Electrodes

4m

m

(a)

HV DC

60mm

30mm

7m

m(b)



001) as

2119889 sin 120579 = 120582 (1)









Inte

nsity

(au

)



2 3 4 5 6 7 8 9 10 1112 (degree)

X-raysource

(a)



Inte

nsity

(au

)

2 3 4 5 6 7 8 9 10 1112 (degree)

X-raysource

(b)




001) while





(a)

(b)









(a) (b)

(c) (d)

(e) (f)

(g) (h)










SEBSLDPEClay






LDPESEBSLDPESEBS5C

1E + 02

1E + 03

1E + 04

1E + 05

1E + 06

Stor

age m

odul

us (P

a)










LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15

160 180 200 220 240 260 280 300


t asymp 140 m1

2

3

5

10

20

30405060708090

99Pr

obab

ility

of f

ailu

re (

)

(a)

LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15

160 180 200 220


t asymp 200 m

120 1401

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

(b)

LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15

t asymp 300 m

80 90 110 120100 140 150 160 170130


1

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

(c)

0 1 25 5 10 15Clay content ()


0

50

100

150

200

250

300Br

eakd

own

stren

gth

(KV

mm

)

(d)






Table2Weibu

llparametersfor

ACbreakd

owntestof

LDPE

claynano

compo

sites

Samplelowast

Thickn

esssim

140120583

mTh

ickn

esssim

200120583

mTh

ickn

esssim

300120583

m120572

(kVmmminus1)

12057395CI

120572

(kVmmminus1)

12057395CI

120572

(kVmmminus1)

12057395CI

Lower

Upp

erLo

wer

Upp

erLo

wer

Upp

erLD

PE206

2496

202

209

172

2556

169

175

137

1659

133

141

LDPE

1C227

2073

222

232

177

2126

173

180

146

1133

140

152

LDPE

25C

248

1826

242

255

185

1941

181

190

144

1143

139

150

LDPE

5C

266

1320

257

275

198

1575

192

204

145

1040

138

151

LDPE

10C

225

2210

220

230

169

1674

164

174

142

966

135

149

LDPE

15C

223

2270

218

227

167

1559

162

172

139

1123

133

145

lowastNum

bero

fspecimensis2

0fora

llsamples













LDPEMALDPEMA1C


t asymp 140 m1

2

3

5

10

20

30405060708090

99Pr

obab

ility

of f

ailu

re (

)

150 175 200 225 250 275 300

LDPEMA25C


(a)


t asymp 140 m1

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

100 150 200 250 300



(b)







120572

(kVmmminus1) 120573



LDPESEBS-MA5C 8 309 709 279 343



LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15


t asymp 200 m

1

2

3

5

10

20

30405060708090

99Pr

obab

ility

of f

ailu

re (

)

200 250 350 400 450 500 550300

(a)


t asymp 200 m

1

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

150 200 400300 500



(b)




4 Conclusion






Acknowledgments



References


















































































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls





Inte

nsity

(au

)



2 3 4 5 6 7 8 9 10 1112 (degree)

X-raysource

(a)



Inte

nsity

(au

)

2 3 4 5 6 7 8 9 10 1112 (degree)

X-raysource

(b)




001) while





(a)

(b)









(a) (b)

(c) (d)

(e) (f)

(g) (h)










SEBSLDPEClay






LDPESEBSLDPESEBS5C

1E + 02

1E + 03

1E + 04

1E + 05

1E + 06

Stor

age m

odul

us (P

a)










LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15

160 180 200 220 240 260 280 300


t asymp 140 m1

2

3

5

10

20

30405060708090

99Pr

obab

ility

of f

ailu

re (

)

(a)

LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15

160 180 200 220


t asymp 200 m

120 1401

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

(b)

LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15

t asymp 300 m

80 90 110 120100 140 150 160 170130


1

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

(c)

0 1 25 5 10 15Clay content ()


0

50

100

150

200

250

300Br

eakd

own

stren

gth

(KV

mm

)

(d)






Table2Weibu

llparametersfor

ACbreakd

owntestof

LDPE

claynano

compo

sites

Samplelowast

Thickn

esssim

140120583

mTh

ickn

esssim

200120583

mTh

ickn

esssim

300120583

m120572

(kVmmminus1)

12057395CI

120572

(kVmmminus1)

12057395CI

120572

(kVmmminus1)

12057395CI

Lower

Upp

erLo

wer

Upp

erLo

wer

Upp

erLD

PE206

2496

202

209

172

2556

169

175

137

1659

133

141

LDPE

1C227

2073

222

232

177

2126

173

180

146

1133

140

152

LDPE

25C

248

1826

242

255

185

1941

181

190

144

1143

139

150

LDPE

5C

266

1320

257

275

198

1575

192

204

145

1040

138

151

LDPE

10C

225

2210

220

230

169

1674

164

174

142

966

135

149

LDPE

15C

223

2270

218

227

167

1559

162

172

139

1123

133

145

lowastNum

bero

fspecimensis2

0fora

llsamples













LDPEMALDPEMA1C


t asymp 140 m1

2

3

5

10

20

30405060708090

99Pr

obab

ility

of f

ailu

re (

)

150 175 200 225 250 275 300

LDPEMA25C


(a)


t asymp 140 m1

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

100 150 200 250 300



(b)







120572

(kVmmminus1) 120573



LDPESEBS-MA5C 8 309 709 279 343



LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15


t asymp 200 m

1

2

3

5

10

20

30405060708090

99Pr

obab

ility

of f

ailu

re (

)

200 250 350 400 450 500 550300

(a)


t asymp 200 m

1

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

150 200 400300 500



(b)




4 Conclusion






Acknowledgments



References


















































































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls





(a)

(b)









(a) (b)

(c) (d)

(e) (f)

(g) (h)










SEBSLDPEClay






LDPESEBSLDPESEBS5C

1E + 02

1E + 03

1E + 04

1E + 05

1E + 06

Stor

age m

odul

us (P

a)










LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15

160 180 200 220 240 260 280 300


t asymp 140 m1

2

3

5

10

20

30405060708090

99Pr

obab

ility

of f

ailu

re (

)

(a)

LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15

160 180 200 220


t asymp 200 m

120 1401

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

(b)

LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15

t asymp 300 m

80 90 110 120100 140 150 160 170130


1

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

(c)

0 1 25 5 10 15Clay content ()


0

50

100

150

200

250

300Br

eakd

own

stren

gth

(KV

mm

)

(d)






Table2Weibu

llparametersfor

ACbreakd

owntestof

LDPE

claynano

compo

sites

Samplelowast

Thickn

esssim

140120583

mTh

ickn

esssim

200120583

mTh

ickn

esssim

300120583

m120572

(kVmmminus1)

12057395CI

120572

(kVmmminus1)

12057395CI

120572

(kVmmminus1)

12057395CI

Lower

Upp

erLo

wer

Upp

erLo

wer

Upp

erLD

PE206

2496

202

209

172

2556

169

175

137

1659

133

141

LDPE

1C227

2073

222

232

177

2126

173

180

146

1133

140

152

LDPE

25C

248

1826

242

255

185

1941

181

190

144

1143

139

150

LDPE

5C

266

1320

257

275

198

1575

192

204

145

1040

138

151

LDPE

10C

225

2210

220

230

169

1674

164

174

142

966

135

149

LDPE

15C

223

2270

218

227

167

1559

162

172

139

1123

133

145

lowastNum

bero

fspecimensis2

0fora

llsamples













LDPEMALDPEMA1C


t asymp 140 m1

2

3

5

10

20

30405060708090

99Pr

obab

ility

of f

ailu

re (

)

150 175 200 225 250 275 300

LDPEMA25C


(a)


t asymp 140 m1

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

100 150 200 250 300



(b)







120572

(kVmmminus1) 120573



LDPESEBS-MA5C 8 309 709 279 343



LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15


t asymp 200 m

1

2

3

5

10

20

30405060708090

99Pr

obab

ility

of f

ailu

re (

)

200 250 350 400 450 500 550300

(a)


t asymp 200 m

1

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

150 200 400300 500



(b)




4 Conclusion






Acknowledgments



References


















































































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls





(a) (b)

(c) (d)

(e) (f)

(g) (h)










SEBSLDPEClay






LDPESEBSLDPESEBS5C

1E + 02

1E + 03

1E + 04

1E + 05

1E + 06

Stor

age m

odul

us (P

a)










LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15

160 180 200 220 240 260 280 300


t asymp 140 m1

2

3

5

10

20

30405060708090

99Pr

obab

ility

of f

ailu

re (

)

(a)

LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15

160 180 200 220


t asymp 200 m

120 1401

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

(b)

LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15

t asymp 300 m

80 90 110 120100 140 150 160 170130


1

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

(c)

0 1 25 5 10 15Clay content ()


0

50

100

150

200

250

300Br

eakd

own

stren

gth

(KV

mm

)

(d)






Table2Weibu

llparametersfor

ACbreakd

owntestof

LDPE

claynano

compo

sites

Samplelowast

Thickn

esssim

140120583

mTh

ickn

esssim

200120583

mTh

ickn

esssim

300120583

m120572

(kVmmminus1)

12057395CI

120572

(kVmmminus1)

12057395CI

120572

(kVmmminus1)

12057395CI

Lower

Upp

erLo

wer

Upp

erLo

wer

Upp

erLD

PE206

2496

202

209

172

2556

169

175

137

1659

133

141

LDPE

1C227

2073

222

232

177

2126

173

180

146

1133

140

152

LDPE

25C

248

1826

242

255

185

1941

181

190

144

1143

139

150

LDPE

5C

266

1320

257

275

198

1575

192

204

145

1040

138

151

LDPE

10C

225

2210

220

230

169

1674

164

174

142

966

135

149

LDPE

15C

223

2270

218

227

167

1559

162

172

139

1123

133

145

lowastNum

bero

fspecimensis2

0fora

llsamples













LDPEMALDPEMA1C


t asymp 140 m1

2

3

5

10

20

30405060708090

99Pr

obab

ility

of f

ailu

re (

)

150 175 200 225 250 275 300

LDPEMA25C


(a)


t asymp 140 m1

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

100 150 200 250 300



(b)







120572

(kVmmminus1) 120573



LDPESEBS-MA5C 8 309 709 279 343



LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15


t asymp 200 m

1

2

3

5

10

20

30405060708090

99Pr

obab

ility

of f

ailu

re (

)

200 250 350 400 450 500 550300

(a)


t asymp 200 m

1

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

150 200 400300 500



(b)




4 Conclusion






Acknowledgments



References


















































































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls









SEBSLDPEClay






LDPESEBSLDPESEBS5C

1E + 02

1E + 03

1E + 04

1E + 05

1E + 06

Stor

age m

odul

us (P

a)










LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15

160 180 200 220 240 260 280 300


t asymp 140 m1

2

3

5

10

20

30405060708090

99Pr

obab

ility

of f

ailu

re (

)

(a)

LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15

160 180 200 220


t asymp 200 m

120 1401

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

(b)

LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15

t asymp 300 m

80 90 110 120100 140 150 160 170130


1

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

(c)

0 1 25 5 10 15Clay content ()


0

50

100

150

200

250

300Br

eakd

own

stren

gth

(KV

mm

)

(d)






Table2Weibu

llparametersfor

ACbreakd

owntestof

LDPE

claynano

compo

sites

Samplelowast

Thickn

esssim

140120583

mTh

ickn

esssim

200120583

mTh

ickn

esssim

300120583

m120572

(kVmmminus1)

12057395CI

120572

(kVmmminus1)

12057395CI

120572

(kVmmminus1)

12057395CI

Lower

Upp

erLo

wer

Upp

erLo

wer

Upp

erLD

PE206

2496

202

209

172

2556

169

175

137

1659

133

141

LDPE

1C227

2073

222

232

177

2126

173

180

146

1133

140

152

LDPE

25C

248

1826

242

255

185

1941

181

190

144

1143

139

150

LDPE

5C

266

1320

257

275

198

1575

192

204

145

1040

138

151

LDPE

10C

225

2210

220

230

169

1674

164

174

142

966

135

149

LDPE

15C

223

2270

218

227

167

1559

162

172

139

1123

133

145

lowastNum

bero

fspecimensis2

0fora

llsamples













LDPEMALDPEMA1C


t asymp 140 m1

2

3

5

10

20

30405060708090

99Pr

obab

ility

of f

ailu

re (

)

150 175 200 225 250 275 300

LDPEMA25C


(a)


t asymp 140 m1

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

100 150 200 250 300



(b)







120572

(kVmmminus1) 120573



LDPESEBS-MA5C 8 309 709 279 343



LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15


t asymp 200 m

1

2

3

5

10

20

30405060708090

99Pr

obab

ility

of f

ailu

re (

)

200 250 350 400 450 500 550300

(a)


t asymp 200 m

1

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

150 200 400300 500



(b)




4 Conclusion






Acknowledgments



References


















































































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls






LDPESEBSLDPESEBS5C

1E + 02

1E + 03

1E + 04

1E + 05

1E + 06

Stor

age m

odul

us (P

a)










LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15

160 180 200 220 240 260 280 300


t asymp 140 m1

2

3

5

10

20

30405060708090

99Pr

obab

ility

of f

ailu

re (

)

(a)

LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15

160 180 200 220


t asymp 200 m

120 1401

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

(b)

LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15

t asymp 300 m

80 90 110 120100 140 150 160 170130


1

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

(c)

0 1 25 5 10 15Clay content ()


0

50

100

150

200

250

300Br

eakd

own

stren

gth

(KV

mm

)

(d)






Table2Weibu

llparametersfor

ACbreakd

owntestof

LDPE

claynano

compo

sites

Samplelowast

Thickn

esssim

140120583

mTh

ickn

esssim

200120583

mTh

ickn

esssim

300120583

m120572

(kVmmminus1)

12057395CI

120572

(kVmmminus1)

12057395CI

120572

(kVmmminus1)

12057395CI

Lower

Upp

erLo

wer

Upp

erLo

wer

Upp

erLD

PE206

2496

202

209

172

2556

169

175

137

1659

133

141

LDPE

1C227

2073

222

232

177

2126

173

180

146

1133

140

152

LDPE

25C

248

1826

242

255

185

1941

181

190

144

1143

139

150

LDPE

5C

266

1320

257

275

198

1575

192

204

145

1040

138

151

LDPE

10C

225

2210

220

230

169

1674

164

174

142

966

135

149

LDPE

15C

223

2270

218

227

167

1559

162

172

139

1123

133

145

lowastNum

bero

fspecimensis2

0fora

llsamples













LDPEMALDPEMA1C


t asymp 140 m1

2

3

5

10

20

30405060708090

99Pr

obab

ility

of f

ailu

re (

)

150 175 200 225 250 275 300

LDPEMA25C


(a)


t asymp 140 m1

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

100 150 200 250 300



(b)







120572

(kVmmminus1) 120573



LDPESEBS-MA5C 8 309 709 279 343



LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15


t asymp 200 m

1

2

3

5

10

20

30405060708090

99Pr

obab

ility

of f

ailu

re (

)

200 250 350 400 450 500 550300

(a)


t asymp 200 m

1

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

150 200 400300 500



(b)




4 Conclusion






Acknowledgments



References


















































































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls





LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15

160 180 200 220 240 260 280 300


t asymp 140 m1

2

3

5

10

20

30405060708090

99Pr

obab

ility

of f

ailu

re (

)

(a)

LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15

160 180 200 220


t asymp 200 m

120 1401

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

(b)

LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15

t asymp 300 m

80 90 110 120100 140 150 160 170130


1

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

(c)

0 1 25 5 10 15Clay content ()


0

50

100

150

200

250

300Br

eakd

own

stren

gth

(KV

mm

)

(d)






Table2Weibu

llparametersfor

ACbreakd

owntestof

LDPE

claynano

compo

sites

Samplelowast

Thickn

esssim

140120583

mTh

ickn

esssim

200120583

mTh

ickn

esssim

300120583

m120572

(kVmmminus1)

12057395CI

120572

(kVmmminus1)

12057395CI

120572

(kVmmminus1)

12057395CI

Lower

Upp

erLo

wer

Upp

erLo

wer

Upp

erLD

PE206

2496

202

209

172

2556

169

175

137

1659

133

141

LDPE

1C227

2073

222

232

177

2126

173

180

146

1133

140

152

LDPE

25C

248

1826

242

255

185

1941

181

190

144

1143

139

150

LDPE

5C

266

1320

257

275

198

1575

192

204

145

1040

138

151

LDPE

10C

225

2210

220

230

169

1674

164

174

142

966

135

149

LDPE

15C

223

2270

218

227

167

1559

162

172

139

1123

133

145

lowastNum

bero

fspecimensis2

0fora

llsamples













LDPEMALDPEMA1C


t asymp 140 m1

2

3

5

10

20

30405060708090

99Pr

obab

ility

of f

ailu

re (

)

150 175 200 225 250 275 300

LDPEMA25C


(a)


t asymp 140 m1

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

100 150 200 250 300



(b)







120572

(kVmmminus1) 120573



LDPESEBS-MA5C 8 309 709 279 343



LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15


t asymp 200 m

1

2

3

5

10

20

30405060708090

99Pr

obab

ility

of f

ailu

re (

)

200 250 350 400 450 500 550300

(a)


t asymp 200 m

1

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

150 200 400300 500



(b)




4 Conclusion






Acknowledgments



References


















































































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls





Table2Weibu

llparametersfor

ACbreakd

owntestof

LDPE

claynano

compo

sites

Samplelowast

Thickn

esssim

140120583

mTh

ickn

esssim

200120583

mTh

ickn

esssim

300120583

m120572

(kVmmminus1)

12057395CI

120572

(kVmmminus1)

12057395CI

120572

(kVmmminus1)

12057395CI

Lower

Upp

erLo

wer

Upp

erLo

wer

Upp

erLD

PE206

2496

202

209

172

2556

169

175

137

1659

133

141

LDPE

1C227

2073

222

232

177

2126

173

180

146

1133

140

152

LDPE

25C

248

1826

242

255

185

1941

181

190

144

1143

139

150

LDPE

5C

266

1320

257

275

198

1575

192

204

145

1040

138

151

LDPE

10C

225

2210

220

230

169

1674

164

174

142

966

135

149

LDPE

15C

223

2270

218

227

167

1559

162

172

139

1123

133

145

lowastNum

bero

fspecimensis2

0fora

llsamples













LDPEMALDPEMA1C


t asymp 140 m1

2

3

5

10

20

30405060708090

99Pr

obab

ility

of f

ailu

re (

)

150 175 200 225 250 275 300

LDPEMA25C


(a)


t asymp 140 m1

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

100 150 200 250 300



(b)







120572

(kVmmminus1) 120573



LDPESEBS-MA5C 8 309 709 279 343



LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15


t asymp 200 m

1

2

3

5

10

20

30405060708090

99Pr

obab

ility

of f

ailu

re (

)

200 250 350 400 450 500 550300

(a)


t asymp 200 m

1

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

150 200 400300 500



(b)




4 Conclusion






Acknowledgments



References


















































































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls
















LDPEMALDPEMA1C


t asymp 140 m1

2

3

5

10

20

30405060708090

99Pr

obab

ility

of f

ailu

re (

)

150 175 200 225 250 275 300

LDPEMA25C


(a)


t asymp 140 m1

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

100 150 200 250 300



(b)







120572

(kVmmminus1) 120573



LDPESEBS-MA5C 8 309 709 279 343



LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15


t asymp 200 m

1

2

3

5

10

20

30405060708090

99Pr

obab

ility

of f

ailu

re (

)

200 250 350 400 450 500 550300

(a)


t asymp 200 m

1

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

150 200 400300 500



(b)




4 Conclusion






Acknowledgments



References


















































































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls





LDPELDPE1CLDPE25C

LDPE5CLDPE10LDPE15


t asymp 200 m

1

2

3

5

10

20

30405060708090

99Pr

obab

ility

of f

ailu

re (

)

200 250 350 400 450 500 550300

(a)


t asymp 200 m

1

2

3

5

10

20

30405060708090

99

Prob

abili

ty o

f fai

lure

()

150 200 400300 500



(b)




4 Conclusion






Acknowledgments



References


















































































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls





References


















































































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls



















































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls




Electrical Breakdown Properties of Clay-Based LDPE Blends and...

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Transcript of Electrical Breakdown Properties of Clay-Based LDPE Blends and...