In this article, the general-purpose polystyrene was reprocessed four times. The effect of repeated reprocessing of polystyrene on its polymeric properties and on its microcellular, foaming behaviour were investigated. It was observed that reprocessing leads to break of long polymeric chains into short chains, which resulted increment in PDI and MFI. Molecular weight and Glass transition temperature were found to decrease with increasing recycling stages. Reprocessing resulted abruptly decrement in viscosity of neat polystyrene. Effect of reprocessing on foaming behaviour was analysed properly in this report and it was found that reprocessing resulted in improvement in cell sizes and their distribution. A positive effect on expansion ratio was also observed during foaming of reprocessed specimens. Cell density was found to decrease with increasing recycling stages. The effect of saturation pressure and foaming temperature on microcellular foam morphology along with recycling were investigated. Effect of foaming time on cell size, cell size distribution, cell density, expansion ratio and cell wall thickness was investigated.

中文翻译：

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多阶段回收诱导聚苯乙烯固态微孔发泡中的形态转变

本文对通用聚苯乙烯进行了四次再加工。研究了聚苯乙烯的重复再加工对其聚合物性质及其微孔发泡行为的影响。据观察，再加工导致长聚合物链断裂为短链，从而导致 PDI 和 MFI 增加。发现分子量和玻璃化转变温度随着回收阶段的增加而降低。再加工导致纯聚苯乙烯的粘度突然降低。本报告正确分析了再处理对发泡行为的影响，发现再处理可改善泡孔尺寸及其分布。在再加工样品的发泡过程中也观察到对膨胀率的积极影响。发现细胞密度随着回收阶段的增加而降低。研究了饱和压力和发泡温度对微孔泡沫形态以及回收的影响。研究了发泡时间对泡孔尺寸、泡孔尺寸分布、泡孔密度、膨胀率和泡孔壁厚度的影响。