Novel biocomposites from biobased PC/PLA blend matrix system for durable applications

Abstract

Polycarbonate (PC) and poly(lactic acid) (PLA) were used to create a blend which was used to as a matrix for high performance glass fiber composites. A novel high temperature blending allowed creating the blend having both high impact strength and high heat resistance. According to Atomic Force Microscopy studies, an impact modifier phase was concentrated almost exclusively in brittle phase allowing the blend to achieve high impact strength with low impact modifier content. Using this high performance PC/PLA blend as a matrix, glass fiber composites were successfully created and characterized. It is found that the small amount of glass fiber loading of bellow 7.5 phr allowed the new PC/PLA blend based composites to maintain excellent elongational properties and good impact strength not observed in most commercial composites. It is found that PLA and PC phases form co-continuous morphology in blend allowing these novel composites reaching high heat resistance of over 133 °C which further increased to over 145 °C in glass fiber composites. Two matrices based on linear and branched PC were prepared and tested. It is found that glass fiber composites based on branched PC/PLA matrix demonstrate superior mechanical and heat resistance properties over linear PC/PLA matrix composites. A competitive weight-to-strength ratio, excellent heat resistance (as compared to commercial PC/ABS composites) as well as relatively low density makes novel biocomposites suitable for wide range of structural and durable applications such as in automotive and electronic industries.