Effects of mixing technique and filler content on physical properties of bovine bone-based CHA/PLA composites

This study presented influence of mixing technique as well as filler content on physical and thermal properties of bovine bone‐based carbonated hydroxyapatite (CHA)/poly(lactic acid) (PLA) composites. CHA/PLA composites at various contents of CHA were prepared by either melt‐mixing or solution‐mixing techniques. Thermal properties, morphologies, and mechanical properties of the CHA/PLA composites including molecular weight deterioration of PLA matrices were investigated. Average molecular weights of PLA in the composites prepared by both techniques decreased with increasing CHA content, whereas their molecular weight distributions (MWDs) increased. Nonetheless, average molecular weights of PLA in melt‐mixed composites were lower than those of solution‐mixed composites. With increasing CHA content, elongation at break, tensile strength, and impact strength of the composites were decreased, whereas the tensile moduli of the composites were increased. In comparison between two mixing techniques, the melt‐mixing distributed and dispersed CHA into PLA matrix more effectively than the solution‐mixing did. Therefore, tensile moduli, tensile strength, and impact strength of the melt mixed composites were higher than those of the solution‐mixed composites of the corresponding CHA content. Moreover, decomposition temperatures and % crystallinity of the melt‐mixed composites were higher than those of the solution‐mixed composites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.