Analysis on Mechanical Properties of Poly-lactic Acid Composites with Organic-Montmorillonite by Injection Molding

摘要

Biodegradable material enacts as an important role on reducing impacts in environment problem. This paper investigated the mechanical properties of Poly-lactic Acid (PLA) and PLA/nanocomposites by variant parameters of injection molding process. Effects on tensile strength between molecular orientation and density have been tested and discussed. The micron clay composites, organic-montmorillonite (OMMT) is used for filler materials in this study, and coupling agent, such as silane has been adopted to enhance polymer branches to catch OMMT and then improved both materials bonding. Effects on mechanical properties by different mixing ratio of pure PLA, PLA/M (PLA with OMMT) and PLA/S/M (PLA with silane and OMMT) clay composites have been prepared and the most significant factor for mechanical properties in tensile and impact strength with injection molding parameters have been obtained. The thermogravimetric analyzer (TGA) and differential scanning calorimetry (DSC) have also been used to measure the thermal properties of such PLA and PLA clay composites. Results show that the tensile properties of PLA/S/M are superior to that of PLA/M and the PLA/S/M4 of 4wt% OMMT has the largest tensile strength as 84.85MPa as increases approximately 8.0% higher than that of pure PLA specimen. However, the impact strength of PLA/M is superior to that of PLA/S/M. The PLA/M4 has the best impact strength as 0.625J/cm2 as increasing 54.3% higher than that of pure PLA specimen. Results of this study can be applied to future applications of in-vivo medical assistive device or fixed scaffold products by injection molding processes.