Impact strength of high density microcellular poly(vinyl chloride) foams

The impact strength of microcellular poly(vinyl chloride) (PVC) produced from an industrial formulation was investigated. The solid-state process with carbon dioxide as the blowing agent was used to prepare the specimens. Processing conditions were explored to produce microcellular PVC with a relative density of 0.6 and higher. These foams were impact tested by using a falling-weight impact tester. Impact strength of microcellular PVC was found to decrease linearly with relative density. The gas saturation pressure did not significantly affect the impact strength of microcellular PVC foams. Microcellular PVC foams with up to 40% reduction in density possessed a normalized mean failure energy of 3.8 J/mm (0.85 in.-lb/0.001 in.).