lecture 11.0-composite 1

8/17/2019 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

lecture 11.0-composite 1

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