Bio-based foams are the solution to environmental concerns raised by petrochemical-based open cell foams used in various industries for sound absorption. While conventional petrochemical-based polymers take centuries to degrade or may not degrade at all, bio-based polymers decompose to bio-mass, water, and carbon dioxide in a matter of months when exposed to proper environment. To increase the potential of replacing current petrochemical foams, mechanical as well as acoustic characteristics of bio-based foams need to be improved. This article studies the effect of blending two bio-based polymers and physics of the blends on acoustic and mechanical properties of resulting polymer composite foams. Different blends of polylactide with three grades of polyhydroxyalkanoates were foamed and characterized based on acoustic and mechanical performance. Rheological properties of pure polymers as well as their blends were studied and effect of polymer blends on acoustic absorption of the resulting foams was investigated. (C) 2014 Wiley Periodicals, Inc.