Physical characteristics of PLLA/PMMA blends and their CO2 blown foams

This paper reports on sample preparation, characterization, CO2 sorption behaviour, and foaming of blends of poly L-lactic acid (PLLA) and poly methyl methacrylate (PMMA) in compositions of 75/25, 50/50, and 25/75 wt%. The crystallization and thermal decomposition behaviours of the polymer blends were found to be dependant on concentration of PLLA in the samples. Annealing the specimens in air at 90°C for 24 hours resulted in complete recrystallization in the 75/25 and 50/50 wt% samples. The interaction of CO2 with PLLA/PMMA blends was investigated and the resultant equilibrium solubility, diffusion coefficient and foam morphologies were compared to those previously reported for neat PLLA and PMMA-CO2 systems.