Evaluation of Fully Biodegradable PLA/PHB Blend Filled with Microcrystalline Celluloses

Abstract

In this work, biodegradable biocomposites were developed using PLA/PHB blend as matrix and two types of microcrystalline cellulose as filler at three different contents. The biocomposites were evaluated regarding their thermal and morphological characteristics and molecular dynamic behavior. It was seen that cellulose addition did not promote significant changes in the Tm, Tc and Tcc in the matrix. On the other hand, XRD and TGA revealed that the addition of the highest content (7 wt%) of cellulose fillers resulted in a more significant decrease in crystallinity and thermal stability of the PLA/PHB matrix, suggesting a formation of filler aggregates. This indication was confirmed by TD-NMR, whose results pointed to a greater heterogeneity molecular in the samples containing higher cellulose contents. Therefore, this technique proved to be a relevant and complementary tool for the characterization of composites materials, contributing to determinate the most appropriate filler content introduced in a polymer matrix.

Keywords

• PLA/PHB blend
• microcrystalline cellulose
• biocomposites
• TGA
• DSC
• XRD
• TD-NMR