ACOUSTIC ABSORBERS MADE OF WOOD FIBER COMPOSITES DEVELOPED BY COMPRESSION MOLDING AND ADDITIVE MANUFACTURING

Abstract

This research aims to address the noise pollution by developing an acoustic absorber made of polylactic acid (PLA)/polyhydroxyalkanoates (PHA)-wood fibers (PLA/PHA-WF) by compression molding (CM) and additive manufacturing (AM). Physical, mechanical, thermal, water absorption, and biodegradation properties of the developed acoustic absorbers by CM and AM were characterized and compared. Upon providing an air gap, thin absorbers developed by AM exhibit an increased and narrow acoustic peak than the CM absorbers because of the Helmholtz resonance effect due to the decreased density and increased porosity in the AM absorber. The results also show that the mechanical and thermal properties of the absorbers developed by CM and AM were almost similar and absorber developed by AM shows an increased rate of water absorption and biodegradation compared to absorber developed by CM due to the presence of porosity in the AM structure.