Lecture 11.0-Composite 1
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POLYMER COMPOSITE
Part 1
POLYMER ENGINEERING AND
PROCESSING
CBB 4423
AP. DR. Zakaria Man
Chemical Engineering DepartmentUniversiti Teknologi PETRONAS
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PRESENTATION OUTLINE
Introduction to Polymer composite
Classification
Thermoplastic based (matrices)
Thermoset based (matrices)
Interphase adhesion
Characterizing the effectiveness of the
reinforcement
Part 1
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Part ii -To estimate fiber-reinforced compositestrength for long continuous fibers in a
matrix- longitudinal (extensional) modulus
- transverse modulus
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INTRODUCTION
COMPONENTS IN A COMPOSITE MATERIAL
Nearly all composite materials consist of two
phases:
1. Primary phase - forms thematrix within which the
secondary phase is imbedded
2. Secondary phase - imbedded phase sometimes
referred to as areinforcing agent, because it usually
serves to strengthen the composite
The reinforcing phase may be in the form of fibers,particles, or various other geometries
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INTRODUCTION
FUNCTIONS OF THE MATRIX MATERIAL
(PRIMARY PHASE)
Provides the bulk form of the part or product made
of the composite material
Holds the imbedded phase in place, usually
enclosing and often concealing it
When a load is applied, the matrix shares the load
with the secondary phase, in some cases deforming
so that the stress is essentially born by the
reinforcing agent
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• Composites:
-- Multiphase material w/significant proportions of each phase
• !ispersed phase: -- Purpose: enhance matrix properties
increase E " σ y" TS " creep resist -- Classification: Particle" fi#er " structural
• Matrix: -- $he continuous phase
-- Purpose is to: - transfer stress to other phases - protect filler/fi#er phases from environment
%eprinted with permission from
! &ull and $' Clne" An Introduction
to Composite Materials" nd ed"
Cam#ridge *niversit Press" +ew ,or"
1.." 0ig " p 23
TERMINOLOGY/CLASSIFICATION
woven
fi#ers
cross
section
view
45 mm
45 mm
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POLYMER COMPOSITE
L a r g e -
p a r t i c l e
D i s p e r s i o n -
s t r e n g t h e n e d
P a r t i c l e - r e i n f o r c e d
C o n t i n u o u s
( a l i g n e d )
A l i g n e d a n d o m l !
o r i e n t e d
D i s c o n t i n u o u s
( s h o r t )
" i b e r - r e i n f o r c e d
L a m i n a t e s # a n d $ i c h
p a n e l s
# t r u c t u r a l
C o m p o s i t e s
Nanocomposite
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1. Thermoplastic ase! "matrices#
$. Thermoset ase! "matrices#
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Thermoplastic ase! "matrices#
PE% PP% P&C an! PS 'ill e(ol(e )rom simple
*commo!it+, pol+mers to *per)ormance,
pol+mers pro!-ce! in -lk
/e' market an! a!! (al-e to rec+cle! pol+mers
e0. Rec+cle! PP
'h composite 6
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Commo!it+, Pol+mer to *per)ormance, Pol+mer
pro!-ce! in -lk
Material !ensit(g/m)
$ensile7trength(M+/m)
0lexuralModulus(8+/m)
9longation at
#rea
Price;
+lon 1124 34 < 4 .
P= 144 4 < 2 2Polsulfone 124 34
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Commo!it+, Pol+mer to *per)ormance, Pol+mer
pro!-ce! in -lk
Capture +ew Marets
7ell at higher price - sell at higher than normal commodit price #ut
lower than the engineering/performance polmer
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USE OF MINERAL FILLERS
(COMPOSITE)
8illers
Particulate / 7pherical
CaCO4
0i#rous
?cicular
9ollastonite
:lass )ires
@amellar"
Talc%
Mica%
Cla+
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WAYS TO ENHANCE PERFORMANCE OF
PP OR OTHER COMODITY POLYMERS
Modification by incorporating fillers / reinforcements after
manufacturing:
Addition ofmineral fillers (stiffness, Heat Deflection
Temperature (HDT), shrinkage reduction)
Addition ofreinforcing fibres (strength, stiffness, impact
resistance, HDT, creep resistance)
Addition ofnatural fibres -wood composite (cost, low density
etc.) Addition ofnanoclay - nanocomposite(stiffness, HDT)
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Depending on the interface;
How do we DESIGN the interface to get theTg we want?
The level of dispersion we desire?
GLASS TRANSITION TEMPERATURE IMPROVEMENT IN NANOCOMPOSITE
Strong interface
Weak interface
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8lame Retar!ant ;
?!A?+$?8 >0 +?+>C>MP>7B$
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PP COMPOSITE
With modifications, PP composite has emergedas material of choice in many sectors viz.Household articles
Appliances (washing machine parts,
refrigerator parts)Furniture (moulded chairs, tables and
benches)
Automobiles (bumpers, IP, interior trims,
door trims)
Moulded luggage
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WPCs are produced by mixing wood flour or fiber &
plastics to produce a material that can be processed
like a conventional plastic & has the best features of
wood & plastic
'>>! P>@,M% C>MP>7B$7 ('PCs)
+' M?%=$ 0>% PP C>MP>7B$7
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WOOD FILLED PP PRODUCTS
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? Composite material is a material sstem? Composite material is a material sstem
composed of two or morecomposed of two or more macro constit-entsmacro constit-ents
that differ in shape and chemical compositionthat differ in shape and chemical composition
and which are insolu#le in each otherand which are insolu#le in each other
Bn 1.24" fi#er glass was first used to reinforceBn 1.24" fi#er glass was first used to reinforce
epoxepox
Thermoset ase! "matrices#
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Stress‑strain relationships for the composite material and itsconstituents. The fiber is stiff but brittle, while the matrix(commonly a polymer) is soft but ductile.
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Epo
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COMPOSITES: FIBER-BASED
Fiberglass is the classic composite:Glass fibers (often woven)
Matrix- polyester
or epoxy resin
Epoxy strength = 60MPaGlass fibertensile
strength = 500 MPa
The composite can achieve a significant percentage
of the fiber strength (300MPa typical),along the fiber direction.
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8I=RES% 8ILLERS "micro or nano si>e#
PP or P>D, %7B+
PER8ORMA/CE IMPRO&EME/T ?
0i#ers or fillers and polmer do not react" #ut the polmer
must adhere ver well to the fi#er for strength
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B+$%0?C ?!&7B>+
CaCO3
Si203
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REINFORCEMENT-MATRIX INTERFACE
The load acting on the matrix has to betransferred to the reinforcement via. Interface
The reinforcement must be strongly bonded to
the matrix if high stiffness and strength are
desired in the composite materials A weak interface results in low stiffness and
strength but high resistance to fracture
A strong interface produces high stiffness andstrength but often low resistance to fracture, i.e.
brittle behavior
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B+$%0?C ?!&7B>+
O H - - - O = C
A l
2
O
7+!ro0en =on!in0
Short 8-nctional :ro-ps
Lon0 8-nctional oli0omers
Property
Enhancing
Block
Matrix
Compatible
Block
R
?dd coupling agent or
7urface modification of fi#er or filler
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After surface treatment of Ag, the dispersivity of Agnanoparticles in epoxy system is remarkably improved.
!a"# $ vol#% o& 'ntreated
system
!b"# $ vol#% o& treated system
($$)($$)
ight microscopy micrographs reveal the degree o& dispersivity Ag in epo+y matri+
be&ore and a&ter chemical treatment o& Ag
SILVER (AG) FILLED EPOXY COMPOSITES; WITH THE
ADDITION OF SILANE COUPLING AGENT (3APTES)
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Characteriing the e&&ectiveness o& the rein&orcement
%atio surface area to volume of reinforcement is important
Bf the surface area of a particle is ? and its volume is A- the surface-to volume ratio ?/A to #e as high as possi#le
0or a clindrical particle l Elength" d Ediameter
2
l d V π =?nd
dl d
A π π
+=
)
?nd conseFuentl
d l V
A 2+=
%ewritten in terms of A and the aspect ratio of the clinder a E l/d
( )1
1
aaV V
A+
= −
π
(1)
()
()
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a (log scale)
Platelet/flae/lamellar 0i#re
441 41 1 14 1444
5
14
15
4
? r e a
/ v o l u m e r a t i o ? / A
i n u n i t s o f ( π / v
) 1 /
$he optimum shape
for the reinforcement G
to maximiHe ?/A Be
a II 1 for a fi#er"
a JJ 1 for a platelet
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E
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%aning results in order of decreasing effectiveness:
c I a I # I d
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&oi!
Bn Practice composite materials contain voids which comprised trapped?ir" solvent etc
? void is a source of weaness
? void content I 9 indicates poor fa#rication
? void content J 459 indicates high-class fa#rication
8ive the exact composite densit G and with
φf " ρf " and ρm nown G the fraction of voids can #e calculated
$he fraction of voids can #e calculated from the difference #etween experimental
and theoretical densities of a particular composite
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E
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7olution:
(a)0irst find the densit of the composite:
m f f f ρ φ ρ φ ρ −+= 1
ρ E 4 x 524 L 4< x .44 E 1< g/m
Bn 1 m of composite" there is 4 m of glass fi#re
-the mass of glass in 1 m of composite E 4 x 524 g E 54< g
-mass of glass in 1 g of composite E 54
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Part BB
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MANUFACTURING & PROCESSINGTHERMOPLASTIC-MATRIX
Two stage Process: Compounded pellets &shaping
Commonly Used processing Techniques Sheets & profile extrusion
Thermoforming
Compression Molding
Injection MoldingNew Trend
In-Line Compounding & Processing
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EXTRUSION
MACHINERYFORWOODPP
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MACHINERY FOR WOOD PP
COMPOSITES
MANUFACTURING&PROCESSING
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MANUFACTURING & PROCESSINGTHERMOSET-MATRIX
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WORKABILITY
Glass, carbon, kevlar sheets and liquid resins areeasy to work with, and used for:Boat making and repair.
Custom surfboards, snowboards…
Motorcyle and auto racing.Furniture (e.g. chairs)…
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COMPOSITE PRODUCTION METHODS
Pultrusion
Continuous fibers pulled through resin tank, then preforming die & oven tocure
Production rates around + m1min2
Applications are to sporting goods (golf club shafts) vehicle drive shafts(because of the high damping capacit!) nonconductive ladder rails
for electrical service and structural members for vehicle and aerospaceapplications2
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PP3 P4D5CT647 P4C###
Prepreg is the composite industr!8s term for continuous fiber
reinforcement pre-impregnated $ith a pol!mer resin that is onl! partiall!cured2
Prepreg is delivered in tape form to the manufacturer $ho then moldsand full! cures the product $ithout having to add an! resin2
This is the composite form most $idel! used for structural applications