Microcellular chlorinated polyethylene (CM) rubber foam by using N2 as blowing agent

Abstract

Microcellular Chlorinated Polyethylene (CM) foams were prepared through the batch-foaming method by using nitrogen as blowing agent. The effects of varying curing time, curing temperature, crosslinking agent content, carbon black content on the cell structure and physical-mechanical properties of CM foam were investigated by scanning electron microscopy (SEM) and universal testing machine (UTM) respectively. The effect of the crosslink density on the CM foaming by varying curing time, curing temperature and crosslink agent revealed that there must be a minimum crosslink density attained in the vulcanizates for its effective foaming. However, when increasing the crosslink density of the vulvanizates beyond the sufficient crosslink density needed for foaming, the average cell sizes of the foams decreased and cell density increased. Expansion of the foams reduce its mechanical properties whereas increase of crosslink density of the matrix improved the mechanical properties. The existence of carbon black caused a decrease in average cell size and increase in cell density for the CM foams, resulting significant increase in mechanical properties of CM foams with increase of carbon black content. The observed phenomenon is attributed with good reinforcing behavior of carbon black to the CM foams.