the foaming process of poly styrene-co-acrylonitrile (san) with co blowing agents

In this work, the poly styrenecoacrylonitrile (san)beads and three blowing agents (co2, n2 and npentane) were used to investigate the foaming process via our batch foaming system. the solubility and diffusivity of three blowing agents were determined by the msb. the solubility of blowing agents was increased by pressure and decreased by temperature increment. it was resulted that the solubility and diffusivity data for san/npentane/co2 system (using coblowing gent) were higher than other samples. according to the scanning electron microscopy (sem) results, it was concluded that the cell and foam densities were decreased with temperature increment and increased by pressure release rate in all foamed beads. with using co blowing agents, higher pressure release rate and low temperature without adding any fillers, we could improve the foam characteristics and produced the san foams with smaller cell sizes and greater cell and foam densities.