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Message: Re:

Effect of Epolene E-43 as a Compatibilizer on theMechanical Properties of Palm Fiber–Poly(propylene)Composites

B. F. Abu-Sharkh, R. Kahraman, S. H. Abbasi, I. A. Hussein

Chemical Engineering Department, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia

Received 9 May 2003; accepted 6 October 2003Published online 00 Month 2004 in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/app.20230

ABSTRACT: Composites of palm fibers and poly(pro-pylene) (PP) were compounded in an extruder at 200°C. Thecomposites were subsequently injection molded into stan-dard tensile specimens for mechanical characterization. Thefracture morphology of the specimens was analyzed byscanning electron microscopy. It was observed that the com-posite modulus increased with the increase of fiber content,indicating the existence of adhesion between PP and themuch stiffer palm fibers. However, the adhesion was notsatisfactory and resulted in a decrease in the compositetensile strength with fiber addition. The compatibilizer

Epolene E-43 was used to minimize this incompatibilitybetween the wood fibers and the PP matrix. The maleatedPP additive enhanced the fiber–matrix adhesion, resulting inan improvement in composite performance. Also, small fi-bers showed better mechanical properties than those of longfibers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93:0000–0000, 2004

Key words: fibers; poly(propylene) (PP); composites; com-patibilization; maleated PP

INTRODUCTION

Composite materials based on fibers of natural poly-mers, such as wood cellulose fibers, and thermoplas-tics continue to attract much attention because of theirremarkable environmental and economical advan-tages. The primary advantages of using cellulosic fi-bers as reinforcements in thermoplastics can be listedas low densities, low cost, nonabrasive nature, possi-bility of high filling levels, low energy consumption,high specific properties, biodegradability, availabilityof a wide variety of fibers throughout the world, andgeneration of a rural/agricultural-based economy.1–10

Poly(propylene) (PP)/wood fiber composites haveattracted special attention because of their wide appli-cability in automobile and panel manufacturing appli-cations. These composites take advantage of the supe-rior properties of PP compared to those of other ther-moplastics, including easy processibility by allprocessing methods (molding, extrusion, film, and fi-ber manufacturing). In addition, PP is far superior topolyethylene in terms of heat resistance and mechan-ical properties. Its low density makes it especiallyattractive in lightweight applications that requirestrength. Furthermore, PP composites can be used in

electrical applications because of their excellent elec-trical properties.

The processing temperature of the cellulosic fibersin thermoplastics is limited, given the potential fiberdegradation at higher temperatures. This limits theirapplication to just the plastics with low melting tem-peratures. However, it has been reported that no de-terioration of properties are observed when process-ing temperatures are maintained below about 200°C.11

It has also been noted that, if the composite composi-tions are treated with sodium borate, boric acid, orphenolic resin, the chance of burning of the composi-tions during processing can be decreased.12,13

The inherent polar and hydrophilic nature of thecellulosic fibers and the nonpolar characteristics ofpolyolefins create difficulties in compounding and re-sult in inefficient composites. However, it has beenshown that the use of compatibilizing and couplingagents for treating fibers before, or as an addition in,the compounding step enhances the compatibility andadhesion between the fibers and the matrix and thefiber dispersion in the matrix, thus improving themechanical properties.14–24 The most commonmethod for compatibilization is grafting matrix-com-patible components to cellulose or grafting cellulose-compatible species to the thermoplastic molecules.Grafting can be achieved using plasma treatment, ion-izing radiation, or reactive chemical additives. An-other compatibilizing method is the use of couplingagents, which are materials that are compatible withcellulose and matrix polymer, such as silanes and

Correspondence to: B. Abu-Sharkh ([email protected]).Contract grant sponsor: KACST, Riyadh; contract grant

number: AR-18-14.

Journal of Applied Polymer Science, Vol. 93, 0000–0000 (2004)© 2004 Wiley Periodicals, Inc.

tapraid5/z8e-polyapp/z8e-polyapp/z8e01404/z8e0502d04a sweigarm S�6 2/6/04 10:47 Art: 20230 Input-wsc

stearic acid.25 Electron-beam treatment of cellulose–thermoplastic composites significantly improved theproperties of the composites in the presence of reac-tive agents.26,27

Various chemical reagents have been used to en-hance the compatibility between the constituent ma-terials. These include Epolene G-3002,28 Epolene E-43(maleic anhydride–modified PP),17 poly[methylene-(polyphenyl isocyanate)]30 (PMPPIC), �-methacrylo-xypropyltrimethoxysilane, poly(propylene acrylicacid), poly(propylene–ethylene acrylic acid),29 and3-aminopropyltriethoxysilane.31

Maleated (maleic anhydride–modified) PP has beenparticularly successful as a coupling agent in cellu-lose–PP composites, improving the mechanical prop-erties as a consequence of enhanced interfacial adhe-sion.4,11,17,30–34 It has been reported that cellulose fi-bers treated with the copolymer turned totallyhydrophobic as a result of the concentration of a con-siderable amount of copolymer on the fiber surfaces.4

It has also been reported that cellulose fibers can besurface modified using propylene–maleic anhydridecopolymers and that the modifying agent was co-valently bonded to the fibers through esterification.35

Another study also showed that the maleic anhydridegrafter styrene–ethylene/butylene–styrene block co-polymer rubber (MAH–SEBS) forms strong chemicalbonds with the surface of the cellulose fibers.36

The objective of this study was to investigate thefeasibility, in terms of mechanical properties, for usingwood fibers obtained from waste palm tree branchesin reinforcing PP with Epolene E-43 (maleated PP) asthe compatibilizer. Palm trees are abundant in theKingdom of Saudi Arabia and PP is locally producedby Saudi Basic Industries (SABIC). If shown to befeasible, the use of waste palm tree branches in rein-forcing thermoplastics would be an economical anduseful service to the environment and society.

EXPERIMENTAL

Materials

Poly(propylene) used in the study was supplied bySABIC (Ladene-PP570P). The melt index of PP is 8(2.16 kg and 230°C, ASTM 1238). It is a homopolymercommonly used for producing rigid injection-moldedarticles, with particular use in houseware items. Thecompatibilizer used in the study was Epolene E-43(maleic anhydride–modified PP), supplied by East-man Chemicals (Rochester, NY). Ethanol (97%) andtoluene (98%) were supplied by BDH (Poole, UK).

Fiber preparation

Branches obtained from local palm trees were cut intopieces about 6 in. long. Thereafter the samples were

dried in the sun for a few days for moisture removal.The pieces of branches were then granulated to a smallsize using a granulator. The fibers were then sizeseparated by use of a sieving machine. Two differentsize distributions of fibers (designated large and smallfibers) were used for the study. The fiber size distri-butions were characterized using a digital vernier cal-iper. The lengths of the fibers were determined to be4.77 � 1.75 and 2.96 � 1.19 mm for large and smallfibers, respectively, both with an aspect ratio of about11.

The obtained fibers were then cleaned to remove theorganic compounds. Ethanol and toluene were usedfor cleaning in the ratio of 1 : 2 (v/v). The mixture ofthese two chemicals was prepared in a large container.The fibers were then soaked in the mixture and keptfor about 2 days. The fibers were then washed withwater and placed in an oven at 80°C to remove themoisture.

Composite processing

Mixing of the composite components was performedin a Model S-650/G126 single-screw extruder (Bra-bender Instruments, South Hackensack, NJ). The fi-bers and the resins were first physically mixed in abowl and then transferred to the extruder. Optimumprocessing conditions that will produce samples withmaximum dispersion of fibers, good mechanical prop-erties, and good color and smell were determinedthrough a detailed investigation. The study of theeffect of compounding techniques will be reported ina separate communication. The mixed composite thusobtained from the extruder had a lumpy shape. It wasgranulated and transferred into a molding machine(Model ES 80/25 ST Pressure 160 bar, T � 200°C;Engel Electronics, Canada) to obtain tensile specimensof ASTM test standard D-648-94B.

Material characterization

The samples were mechanically characterized usingan Instron 5560 mechanical testing machine (Instron,Poole, UK) according to ASTM test standard D-638.The tests were conducted at a constant strain rate of 2mm/min.

The thermal characterization was carried out in aMettler Toledo DSC 822C Star thermal analysis system(Columbus, OH). Weight of the samples was about 5mg. All samples were subjected to the same samplethermal history by first heating to 220°C, and coolingfrom 220 to 20°C at a rate of 10°C/min. Thereafter thesamples were heated at 10°C/min to 220°C.

A JSM-T-300 scanning electron microscope (JEOL,Tokyo, Japan) was used to analyze the fracture surfaceof the composites from the tensile tests. The objectivewas to obtain information regarding the effect of the

2 ABU-SHARKH ET AL.

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compatibilizer on fiber dispersion and adhesion qual-ity between fibers and the matrix. A JEOL fine-coat ionsputter was used to coat a thin layer of gold on thespecimen to avoid electrostatic charging during exam-ination. The fracture ends of the specimens werethereafter mounted on an aluminum stub for analysis.

RESULTS AND DISCUSSION

Figure 1 shows the effect of fiber size and content onthe tensile modulus of the palm fiber–PP composite.As seen in the figure, the increase in fiber contentincreases the composite modulus for both small andlarge fibers, which is an indication of the existence ofadhesion, to some extent, between PP and much stifferpalm fibers. For both small and large fibers, the in-crease in fiber content up to 30% showed only a slightincrease in modulus. However, increasing the fibercontent above 30% resulted in an appreciable increasein modulus.

Figure 2 shows the effect of fiber size and content onthe tensile strength of palm fiber–PP composites. Asthe fiber content is increased, the tensile strength de-creased. This might be attributed to the poor adhesionbetween the fiber and PP. Thus, does this result con-tradict the improvement in composite stiffness withfiber addition as just discussed above? The answer isno. The modulus is related to the stiffness of the

material before fracture and it is obtained from theslope of the straight portion of the stress–strain curve.Existence of adhesion (even weak) between fibers andthe matrix would then improve the composite modu-lus. However, composite tensile strength is a result ofmaterial fracture at the weakest point of the material,which might occur below the matrix (PP) strength ifthe adhesion between the fibers and the matrix fails ata lower stress.

As also shown in Figures 1 and 2, the difference inthe results obtained with small or large fibers was notsignificant, considering also the scatter in data. How-ever, the composite strength with small fibers was stillobserved to be consistently higher than that with largefibers, whereas the same effect was not observed in thecase of composite modulus. This was probably be-cause of better mixing and more uniform distributionof small fibers in the PP matrix than that of largefibers. It is known that the composite propertiesgreatly depend on the fiber aspect ratio.37 Given thatboth small and large fibers have the same aspect ratio,the lower strength observed in the long fiber compos-ites may be attributed to fiber–fiber interaction. Accu-mulation or nonuniform orientation of fibers at someparts of the composite can result in fracture at theseweak points, thus giving lower strength in the case oflarger fibers. Nonuniformities in fiber distributionhere and there (if not so extensive) would not affect

Figure 1 Tensile modulus versus fiber content for PP reinforced with small and large palm fibers.

PALM FIBER–POLY(PROPYLENE) COMPOSITES 3

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Figure 2 Tensile strength versus fiber content for PP reinforced with small and large palm fibers.

Figure 3 Tensile strength versus fiber content for palm fiber–PP matrix composites compatibilized by 2 wt % Epolene E-43.

4 ABU-SHARKH ET AL.


Figure 4 Tensile modulus versus fiber content for palm fiber–PP matrix composites compatibilized by 2 wt % Epolene E-43.

Figure 5 Tensile strength versus fiber content for palm fiber–PP matrix composites compatibilized by 4 wt % Epolene E-43.



Figure 6 Tensile modulus versus fiber content for palm fiber–PP matrix composites compatibilized by 4 wt % Epolene E-43.

Figure 7 Tensile modulus versus fiber content for PP reinforced with large palm fibers without any treatment and with useof compatibilizer Epolene E-43 at various amounts.

6 ABU-SHARKH ET AL.


Figure 8 Tensile modulus versus fiber content for PP reinforced with small palm fibers without any treatment and with useof compatibilizer Epolene E-43 at various amounts.

Figure 9 Tensile strength versus fiber content for PP reinforced with large palm fibers without any treatment and with useof compatibilizer Epolene E-43 at various amounts.



Figure 10 Tensile strength versus fiber content for PP reinforced with small palm fibers without any treatment and with useof compatibilizer Epolene E-43 at various amounts.

Figure 11 Tensile strength versus compatibilizer content for PP reinforced with palm fibers without any treatment and withuse of compatibilizer Epolene E-43 at various amounts.

8 ABU-SHARKH ET AL.


the composite modulus to the same extent because themodulus is a bulk material property before fracture.

The next step was to use the compatibilizer to in-vestigate its effect on composite performance. Figures3 and 4 show the effect of adding 2 wt % Epolene E-43with varying fiber loading and fiber length distribu-tion on the tensile strength and modulus of the com-posite, respectively. The composite behavior is similarto that of the uncompatibilized one. Again, the tensile

strength decreases as fiber loading is increased. Smallfibers result in somewhat better composite strengththan large fibers, and the modulus increases with in-creasing fiber loading. However, higher compositestrength values, relative to those of uncompatibilizedones, is an indication of improvement in fiber–matrixadhesion with 2 wt % Epolene E-43.

Figures 5 and 6 show the effect of adding 4 wt %Epolene E-43 on composite strength and moduluswith varying fiber loading and fiber length distribu-tion. The composite behavior is similar to that of thecomposite compatibilized with 2 wt % Epolene E-43,just discussed above. The performance of the compos-ite with 6 wt % compatibilizer Epolene E-43 was notdifferent either (results are not shown here).

The results discussed above are combined togetherin Figures 7–10, to show the effect of compatibilizeramount on the composite properties in a more conve-nient way for PP reinforced with small and large palmfibers. As seen in Figures 7 and 8 the composite mod-ulus increases with fiber content for composites withthe compatibilizer added at various amounts (2, 4, and6 wt %), as well as for those with no compatibilizer. Asalso discussed above, this is an indication of the exis-tence of adhesion between palm fibers and the PPmatrix even in the composites without any compati-bilizer.

However, the use of compatibilizer might have in-creased the adhesion strength, which is not that clear

Figure 12 DSC results of percentage crystallinity versus fiber content for PP/fiber composite.

Figure 13 SEM micrograph of a fractured surface of a 30 wt% palm fiber–PP composite with small fibers and no com-patibilizer.


F4

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in the plots of modulus versus fiber content (consid-ering also the scatter in data), although this phenom-enon is quite clear in Figures 9 and 10, which presentplots of tensile strength versus fiber content for un-compatibilized and compatibilized palm fiber–PPcomposites with small and large fibers. As seen andalso as discussed previously, there is an obvious im-provement in tensile strength with addition of thecompatibilizer.

The data presented above can be rearranged to beable to discuss the effect of varying compatibilizercontent on the mechanical properties of the PP com-posite. Figure 11 shows the tensile strength versus

compatibilizer content for Epolene E-43 with varyingfiber loading. It is seen as a general trend for the twofiber length distributions that increasing the amountof compatibilizer content increases the tensile strength(even though not so significantly), which is an indica-tion of a probable increase in fiber–matrix adhesionstrength. Because Epolene E-43 is a derivative of PP, itis compatible with PP. Epolene E-43 serves as a bridgethat couples the incompatible phases. The maleic an-hydride groups form bonds with the fiber, whereasthe nonpolar part of Epolene E-43 becomes entangledwith the PP matrix. This bridging action results in theobserved increase in strength.35,36

Figure 14 SEM micrograph of a fractured surface of a 30 wt % palm fiber–PP composite with small fibers and nocompatibilizer (a close-up of Fig. 13).

Figure 15 SEM micrograph of a fractured surface of a 30 wt % palm fiber–PP composite (with small fibers) compatibilizedwith 6 wt % Epolene E-43.

10 ABU-SHARKH ET AL.

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To investigate the influence of fiber content on crys-tallinity, DSC was used to measure the percentagecrystallinity (Xc) of PP in the compatibilized PP/fibercomposites as a function of fiber content. As shown inFigure 12, increasing fiber content was found toslightly increase the Xc of the polymer matrix. Thissuggests that the crystalline cellulose fibers enhancedthe chain folding of PP, possibly by providing a tem-plate for its crystallization. However, the increase incrystallinity was not significant enough to explain theincrease in modulus of the compatibilized compositewith fiber content. To determine the influence of fi-ber/matrix bonding on properties, SEM was used tocharacterize the fracture surfaces.

Fracture surfaces of the mechanically tested com-posite specimens were analyzed by SEM. It was seenthat PP composites containing no compatibilizer re-sulted in rough fracture surfaces with extensive fiberpullout (Figs. 13 and 14). This is an indication of poorbonding between the fibers and the PP matrix (com-pared to that of the composites with compatibilizer-treated fibers, discussion of which will follow). Thisexplains why composites with untreated fibers per-form worse than those with compatibilizer-treated fi-bers. In addition, the SEM micrographs reveal that thepalm fiber forms an irregular shape with the matrix,indicating poor mixing. Proper mixing plays an im-portant role in enhancing the adhesion between fibersand matrix material.38 The effect of using differentcompounding techniques on strength of the compos-ites will be discussed in a future publication.

Once the compatibilizer Epolene E-43 was incorpo-rated, it was observed that instead of fiber pullout, asmoother fracture surface is observed (Figs. 15 and 16)compared to that of the composite without the com-

patibilizer (Figs. 13 and 14). The reason for this phe-nomenon is probably that the incorporation of thecompatibilizer E-43 enhanced the interfacial adhesionbetween the fibers and matrix and that is why a higherload was transferred onto the fibers; thus a highercomposite strength was observed.

CONCLUSIONS

1. An increase in PP modulus with fiber additionwas observed, indicating the presence of adhe-sion between palm fibers and PP.

2. However, the fiber–matrix bond strength in thepalm fiber–PP system was not satisfactory, re-sulting in a decrease in PP strength with fiberaddition.

3. Small fibers resulted in better composite perfor-mance than that of large fibers because of bettermixing and more uniform distribution of smallfibers in the PP matrix.

4. Use of the compatibilizer Epolene E-43 im-proved the fiber–matrix adhesion, resulting inan improvement in composite performance.

The authors gratefully acknowledge the financial supportprovided by KACST, Riyadh under Grant AR-18-14 and thefacilities provided by KFUPM, Dhahran. The authors alsothank Eastman Chemicals for supplying the Epolene com-patibilizer.

References

1. Bourban, Ch.; Karamuk, E.; de Fondaumiere, M. J.; Ruffieux, K.;Mayer, J.; Wintermantel, E. J Environ Polym Degrad 1997, 5, 159.

2. Chen, H. S.; Porter, R. S. J Appl Polym Sci 1994, 54, 1781.

Figure 16 SEM micrograph of a fractured surface of a 30 wt % palm fiber–PP composite (with small fibers) compatibilizedwith 6 wt % Epolene E-43 (a close-up of Fig. 15).


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F14

F16


3. Devi, L. U.; Bhagawan, S. S.; Thomas, S. J Appl Polym Sci 1997,64, 1739.

4. Felix, J. M.; Gatenholm, P. J Appl Polym Sci 1991, 42, 609.5. George, J.; Bhagawan, S. S.; Prabhakaran, N.; Thomas, S. J Appl

Polym Sci 1995, 57, 843.6. Jain, S.; Kumar, R. Mater Manuf Process 1994, 9, 813.7. Mansour, O. Y.; Kamel, S.; Nassar, M. A. J Appl Polym Sci 1998,

69, 845.8. Matuana, L. M.; Park, C. B.; Balatinecz, J. J. Polym Eng Sci 1998,

38, 1862.9. Sanadi, A. R.; Young, R. A.; Clemons, C.; Rowell, R. M. J Rein-

forced Plast Compos 1994, 13, 54.10. Yam, K. L.; Gogoi, B. K.; Lai, C. C.; Selke, S. E. Polym Eng Sci

1990, 30, 693.11. Sanadi, R.; Caulfield, D. F.; Jacobson, R. E.; Rowell, R. M. Ind

Eng Chem Res 1995, 34, 1889.12. Sain, M. M.; Kokta, B. V.; Maldas, D. J Adhes Sci Technol 1993,

7, 49.13. Sain, M. M.; Kokta, B. V. J Appl Polym Sci 1994, 54, 1545.14. Belgacem, M. N.; Batasille, P.; Sapieha, S. J Appl Polym Sci 1994,

53, 379.15. Canche, E. G.; Rodriguez, T. G.; Herrera, F. P.; Mendizabal, E.;

Puig, J. E. J Appl Polym Sci 1997, 66, 339.16. Coutinho, F. M. B.; Costa, T. H. S.; Carvalho, D. L. J Appl Polym

Sci 1997, 65, 1227.17. Felix, J. M.; Gatenholm, P. J Appl Polym Sci 1993, 50, 699.18. Garnett, J. L.; Ng, L. T. Radiat Phys Chem 1996, 48, 217.19. Herrera-Franco, P. J.; Aguilar-Vega, M. D. J. J Appl Polym Sci

1997, 65, 197.20. Karnani, R.; Krishnan, M.; Narayan, R. Polym Eng Sci 1997, 37,

476.

21. Maldas, D.; Kokta, B. V. J Appl Polym Sci 1990, 41, 185.22. Maldas, D.; Kokta, B. V. Polym J 1991, 23, 1163.23. Raj, R. G.; Kokta, B. V.; Dembele, F.; Sanschagrain. J Appl Polym

Sci 1989, 38 1987.24. Raj, R. G.; Kokta, B. V.; Grouleau, G.; Daneault, C. Polym Plast

Technol Eng 1990, 29, 339.25. Bledzki, A. K.; Reihmane, S.; Gassan, J. J Appl Polym Sci 1996,

59, 1329.26. Czvikovsky, T. Periodica Polytech Mech Eng 1994, 38, 209.27. Czvikovsky, T. Radiat Phys Chem 1996, 47, 425.28. Rana, A. K.; Mandal, A.; Mitra, B. C.; Jacobson, R.; Rowell, R.;

Banerjee, N. J Appl Polym Sci 1998, 69, 329.29. Rozman, H. D.; Tan, K. W.; Kumar, R. N.; Abubakar, A.; Ismail,

H.; Ishak, Z. A. M. Eur Polym J 2000, 36, 1483.30. Raj, R. G.; Kokta, B. V.; Maldas, D.; Daneault, C. J Appl Polym

Sci 1989, 37, 1089.31. Rozman, H. D.; Peng, G. B.; Ishak, Z. A. M. J Appl Polym Sci

1998, 70, 2647.32. Felix, J. M.; Gatenholm, P.; Schreiber, H. P. Polym Compos 1993,

14, 449.33. Gauthier, R.; Joly, C.; Coupas, A. C.; Gauthier, H.; Escoubes, M.

Polym Compos 1998, 19, 287.34. Sain, M. M.; Kokta, B. V.; Imbert, C. Polym Plast Technol Eng

1994, 33, 89.35. Felix, J. M.; Gatenholm, P. J Appl Polym Sci 1991, 42, 609.36. Hedenberg, P.; Gatenholm, P. J Appl Polym Sci 1995, 56, 641.37. Glasser, W. G.; Taib, R.; Jain, R. K.; Kander, R. J Appl Polym Sci

1999, 73, 1329.38. Rozman, H. D.; Peng, G. B.; Mohd Ishak, Z. A. J Appl Polym Sci

1998, 70, 2647.

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AQ: 2


AQ1: City in Canada?

AQ2: Ref. 35 is a duplicate of Ref. 4. Do you mean to substitute another entry at 35 instead of a duplicate?If not, please delete and renumber the last three refs. as 35–37 (both in the Ref. listing and in text); changein-text references to the “old” 35 as Ref. 4.

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