Civil Engineering Reference
In-Depth Information
0.8
2.5%
5%
7.5%
10%
0%
0.6
0.4
0.2
0.0
140
150
160
170
180
Temperature (°C)
Figure 13.8
Tan δ curves of nanocomposites at dif erent kenaf whiskers content.
13.4.4.2
Ef ect of Kenaf Whiskers Reinforcement on Tan δ
h e elastic nature of i ber and shear stress concentration at the i ber ends af ected the
tan δ value when incorporated in a composite material, which is related to the addi-
tional viscoelastic energy dissipation in the matrix material [15]. Figure 13.8 shows a
selection of tan δ curves in which it can be seen that the tan δ peak shit ed to the higher
temperatures, broadened, and decreased as the kenaf whiskers content increased. h e
decrease of tan δ value indicated the reduction of macromolecular mobility of the i ber
surface environment, whereas better interaction between kenaf whiskers and matrix
can be concluded [16].
As listed in Table 13.6 , the peak heights of tan δ at the percentage of reinforcement
10% decrease to half of the neat CAB value. When the percentage of reinforcement is
too low, the packing of the whiskers behaves inei ciently in composite system resulting
in the failure of the bonding at the interfacial region [17]. Otherwise, closer packing of
the whiskers will prevent crack propagation. Whiskers reinforcement at 10% gave the
lowest peak height of 0.38, whereas it can be concluded that the most ef ective stress
transfer takes place in this composite system compared to others, even more upon neat
matrix. Better interfacial interaction is attained at this whiskers loading. h is result is
consistent with the storage modulus values.
13.5
Conclusions
h e main objective of this study was to evaluate chemical, thermal and dynamic
mechanical properties of the resulted nanocomposite from kenaf and cellulose acetate
butyrate (CAB). Whiskers-matrix compatibility was evaluated by all of the character-
izations to see the interaction between whiskers and matrix. Based on the i ndings,
FTIR analysis showed no intermolecular hydrogen bonding between CAB and whis-
kers. h ermal analysis found that whiskers reinforcement did not af ect the decomposi-
tion temperature of resulted nanocomposite. However, good miscibility was detected
