Physical Characteristics of PLLA/PMMA Blends and Their CO2 Blowing Foams*

ABSTRACT: This article reports on sample preparation, characterization, CO2 sorption behavior, and foaming of blends of poly L-lactic acid (PLLA) and poly methyl methacrylate (PMMA) in compositions of 75/25, 50/50, and 25/75wt.%. The crystallization and thermal decomposition behavior of the polymer blends were found to be dependant on concentration of PLLA in the samples. Annealing the specimens in air at 90C for 24 h resulted in complete recrystallization in the 75/25 and 50/50wt. % samples. Detailed studies on the sorption kinetics of CO2 in the prepared blend samples indicated gas solubilities to be comparable to those observed in neat PMMA, however, foam morphologies significantly improved in the blends when compared to neat PLLA. KEY WORDS: blends, poly L-lactic acid (PLLA), poly methyl methacrylate (PMMA), foams, crystallization, CO2