Biocomposites of kenaf fiber (KF) and polylactic acid (PLA) were prepared by an internal mixer and compression molding. PLA was plasticized with polyethylene glycol (PEG) (10 wt%) and evaluated as the polymer matrix (p-PLA). Fiber loadings were varied between 0 and 40 wt%. The tensile, dynamic mechanical, and morphological properties and water absorption behavior of these composites were studied. Reinforcing effect of KF was observed when fiber loading exceeded 10 wt% despite of the inferior fiber-matrix adhesion observed via scanning electron microscopy (SEM). Un-plasticized PLA/KF composite exhibited higher tensile properties than its plasticized counterpart. Fiber breakage and heavily coated short pulled-out of fibers were observed from the SEM micrographs of the composite. The presence of PEG might have disturbed the fiber-matrix interaction between KF and PLA in the plasticized composites. Addition of PEG slightly improved the un-notched impact strength of the composites. Dynamic mechanical analysis showed that the storage and loss moduli of p-PLA/KF composites increased with the increase in fiber loading due to increasing restrictions to mobility of the polymer molecules. The tan delta of the composites in contrast showed an opposite trend. p-PLA and p-PLA/KF composites exhibited non-Fickian behavior of water absorption. SEM examination revealed microcracks on p-PLA and p-PLA/KF surfaces.
All Science Journal Classification (ASJC) codes
- Ceramics and Composites
- General Chemistry
- Polymers and Plastics
- Materials Chemistry