Microstructure and thermal stability of polypropylene/bagasse composite foams

Abstract

Wood–plastic composite foams (WPCFs), consisting of polypropylene and bagasse as wood fiber, were produced using tandem extrusion. The simultaneous effects of different material parameters including bagasse loading and particle size, melt viscosity of the used thermoplastic, type and content of chemical blowing agent on the microstructure, and physical properties of the obtained composite foams have been evaluated. Special sandwich morphology has been observed for these foams. Void fraction of WPCFs was measured and optimized using an experimental design method, response surface methodology. The maximum determined void fraction of the prepared WPCFs was 54%, which was obtained at the middle values of blowing agent content and bagasse particle size. Employing a mixture of endothermic–exothermic blowing agents has also caused the optimum amount of void fraction. Moreover, thermal behavior of wood–plastic composites was studied and the effects of all material parameters on decomposition behavior of polymer and bagasse fibers were investigated. The results verify that both bagasse content and bagasse particle size considerably influence the thermal stability of the microcomposites.