156
6
Guth and Smallwood also proposed a relation to predict the modulus of particulate filled composites by
E E
c
p
f
f
/
.
.
= +
+
1 2 5
14 1
φ
φ
(6.4)
where ϕ m is the volume fraction of the matrix.
? Example 6.2 Calculate the modulus of alumina whiskers in
reinforced PP where alumina is 30% by weight. The specific
gravities of PP and alumina are 0.94 and 2.6, respectively. The
modulus of PP is 3 GPa.
v Answer
Volume of alumina = Mass/Density
Volume % of alumina = 30/2.6 = 11.54%
Volume % of PP = 88.46%
ϕ r = 0.1
ϕ m = 0.9
E c /E p = 1 + 2.5 ϕ r + 14.1 ϕ m
So,
E c = 41.8 GPa
6.4 Thermoplastic Composites
Thermoplastic composites have created a niche for themselves due
to their ease of processability, repeated quality, good damage tolerance, and low risk of environmental hazards. They are finding applications in automobiles, aviation, packaging, refrigeration, etc.
[13–16]. The moulding of thermoplastic composites does not
involve any curing mechanism; rather, it involves the melting of the
matrix and its solidification as a function of heat. The characteristics of thermoplastic matrices are given in . Table 6.1.
. Table 6.1 Characteristics of thermoplastic matrices
Serial No.
Parameters
Thermoplastics
1.
Shelf life
Unlimited
2.
Fabrication time
Short
3.
Post formability
Possible
4.
Generation of by products
Almost nil
5.
Tooling
Expensive
6.
Mixing of chemicals
Not required
7.
Production rate
Fast
8.
Economy
High
9.
Handling
Easy
10.
Recycling
Possible
Chapter 6 · Processability of Thermoplastic Composites
6
Guth and Smallwood also proposed a relation to predict the modulus of particulate filled composites by
E E
c
p
f
f
/
.
.
= +
+
1 2 5
14 1
φ
φ
(6.4)
where ϕ m is the volume fraction of the matrix.
? Example 6.2 Calculate the modulus of alumina whiskers in
reinforced PP where alumina is 30% by weight. The specific
gravities of PP and alumina are 0.94 and 2.6, respectively. The
modulus of PP is 3 GPa.
v Answer
Volume of alumina = Mass/Density
Volume % of alumina = 30/2.6 = 11.54%
Volume % of PP = 88.46%
ϕ r = 0.1
ϕ m = 0.9
E c /E p = 1 + 2.5 ϕ r + 14.1 ϕ m
So,
E c = 41.8 GPa
6.4 Thermoplastic Composites
Thermoplastic composites have created a niche for themselves due
to their ease of processability, repeated quality, good damage tolerance, and low risk of environmental hazards. They are finding applications in automobiles, aviation, packaging, refrigeration, etc.
[13–16]. The moulding of thermoplastic composites does not
involve any curing mechanism; rather, it involves the melting of the
matrix and its solidification as a function of heat. The characteristics of thermoplastic matrices are given in . Table 6.1.
. Table 6.1 Characteristics of thermoplastic matrices
Serial No.
Parameters
Thermoplastics
1.
Shelf life
Unlimited
2.
Fabrication time
Short
3.
Post formability
Possible
4.
Generation of by products
Almost nil
5.
Tooling
Expensive
6.
Mixing of chemicals
Not required
7.
Production rate
Fast
8.
Economy
High
9.
Handling
Easy
10.
Recycling
Possible
Chapter 6 · Processability of Thermoplastic Composites