Poly(l-lactide)/poly(d-lactide)/bamboo fiber (BF) bio-composites with enhanced heat resistance, mechanical and rheological performance

Abstract

Natural-fiber-reinforced poly(lactic acid) (PLA) is a simple and effective method to improve properties with retaining the fully biodegradability and eco-friendliness. Herein, we prepared the poly(l-lactic acid) (PLLA)/poly(d-lactic acid) (PDLA)/bamboo fiber (BF) bio-composites through melt compounding. The stereocomplex PLA (SC-PLA) was formed during the melt blending. The SC-PLA crystals combined with BFs in the PLLA/PDLA/BF bio-composites had synergistic effects that could enhance crystallization rate, rheological and mechanical properties, and heat resistance. The results showed that the SC-PLA crystals drastically increased the nucleation density and accelerated the crystallization process of the bio-composites. The rheological properties of the bio-composites were obviously enhanced by the incorporation of BFs and PDLA. Mechanical properties of the bio-composites were increased compared to neat PLLA. The bio-composite with 10 wt% PDLA showed tensile strength of 72.4 MPa, and Young’s modulus of 2855 MPa, which were 9.4% and 18% higher than those of neat PLLA, respectively. Moreover, Vicat softening temperature (VST) of the bio-composites was about 90 °C higher than that of neat PLLA. Overall, this work provides an interesting strategy of fabrication of the BFs reinforced PLA composites with controllable properties.