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

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