(205e) Thermal and Mechanical Properties of Polylactide-Nanoporous Zeolite Composites
AIChE Annual Meeting
Tuesday, November 18, 2008 - 10:10am to 10:35am
Polylactide (PLA) and its composites have gained significant attention due to their bio-based origin. This study investigates the inclusion of nanoporous zeolite particles in PLA with the purpose of obtaining multifunctional polylactide composite materials. PLA (94 % L-lactide) containing 0, 1, 3, and 5 wt. % zeolites (Type 4A) was successfully fabricated using a mini twin screw extruder and injection molder. The effects of the amount of zeolite on morphology, mechanical, and thermal properties of PLA composites were investigated. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) studies revealed a homogeneous distribution of zeolites in the PLA matrix and good interfacial adhesion between the zeolites and the PLA matrix. The addition of zeolites was shown to increase the crystallinity of PLA. The storage modulus measured by dynamic mechanical analysis (DMA) increased with increasing zeolite content. A similar trend was also observed for tan delta values. The tan delta peaks were much higher and broader for composites of PLA with zeolite compared with neat PLA, indicating improved damping properties. Thermal degradation behavior of PLA and PLA/zeolite composites was investigated using thermogravimetric analysis (TGA). The activation energies for thermal degradation (Ea) were estimated at different weight loss values of 2.5 ? 90 % using Flynn-Wall-Ozawa Methods. The activation energies of PLA and PLA with 5 wt. % zeolite composites were found to be in the range of 110-119 kJ/mol and 71-101 kJ/mol, respectively.