4. Conclusions
In this study, the fabrication of PLA/CNF nanocomposite using solution casting was investigated. The morphology
studies of PLA and its nanocomposites showed that relatively good dispersionwas achieved and no agglomerations
of CNF were observed in the fracture surfaces of PLA/CNF1 and PLA/CNF3 nanocomposites. PLA/CNF5, however,
showed small aggregates, indicating that the nanofibers were not well-dispersed in the matrix. SEM and AFM micrographs
indicated that, the surface roughness and phase separation increased with increasing CNF content. This is due to the aggregation of nanofibers, leading to the reduced compatibility of biopolymer. The evaluation of the mechanical
properties of the PLA and its nanocomposites showed a trend where the tensile strength and modulus improved with increased nanofiber content. The modulus of the PLA increased from 1.17 GPa to 2.12 GPa with the addition of 5 wt% CNF, and a 100% increase of tensile strength was observed. The elongation at break was greatly increased up to 3 wt% CNF but then declined abruptly at 5 wt%. The reinforcing effect of nanofibers caused a slight increase in glass transition and melting temperatures of PLA/CNF nanocomposites. The water transmission only increased slightly up to 3 wt% CNF but there was an increase of 38.5% at 5 wt%.