Preparation and characterization of uniaxial poly(lactic acid)-based self-reinforced composites

Uniaxial poly(lactic acid)-based self-reinforced composites have been developed by bonding poly (Llactic acid) (PLLA) fibers by depositing poly(D, L-lactic acid) (PDLLA) which was dissolved in ethyl acetate. The microstructure and the thermal and mechanical properties of this self-reinforced composite have been characterized using scanning electron microscopy, dynamic mechanical analysis, and tensile testing. The results revealed that after ethyl acetate treatment, the PLLA fibers maintained their geometry and orientation well, had an increased crystallinity, and showed a slightly damaged surface. Electron microscopy and thermal analysis showed that the interface between the PLA fiber and the PLA matrix had good compatibility, which was expected since they possess the same chemical structure. The modulus, tensile strength, and elongation, as well as the thermal stability of uniaxial poly(lactic acid) self-reinforced composites, were all significantly greater than those of the PDLLA film. The results showed that we have developed a method to prepare PLA composites with enhanced mechanical properties, without the problem of narrow processing temperature window normally required when using traditional thermal processing techniques.