3.3. Mechanical properties
The effects of MCC loading on the tensile properties of pure PLA
and PLA/MCC composites are shown in Fig. 3. As can be seen in
Fig. 3, incorporation of MCC into the PLA matrix did not show any
improvements in both tensile strength and elongation at break of
the composites as compared to pure PLA. However the Young’s
modulus was increased from 3.9 GPa to 4.6 GPa with increased MCC
loading. The increase in modulus with increasing MCC loading in
PLA can be explained by increased in hydrogen bonding, stiffening
effect and high crystallinity index of the filler which is a typical
characteristics filler/polymer composites (Cheng, Wang, & Rials,
2009). As reported in our previous paper, the relative crystallinity
index of MCC obtained was 87% of cellulose I which may have
also contributed to the increase in theYoung’s modulus of PLA/MCC
composites (Kemala, Budianto, & Soegiyono, 2012).