Static batch foaming is used in a model investigation aiming to understand and predict the impact of resin molecular structure on the foamability of random copolymers of polypropylene (RCP) for bead foam applications. The foaming behavior of seven polypropylene based resins with ethylene content varying from 0 to 11 mol% can be categorized into two groups related to their respective degrees of regio-defects: below 0.1 and around 0.66 mol%. Increasing the ethylene content from 0 to 4.04 mol% is enough to decrease the foam density by a factor of 6.3, as well as the foaming temperature by 15 °C. For a specific number of stereo and regio-defects, the ethylene content has a linear response with the optimal foaming temperature. Regio-defect impact exhibits a similar linear behavior; however, it is decoupled from ethylene content effects. A hierarchical relationship between the polycrystallinity and the foam mechanism was then drawn. The stress induced by the foam cell growth was shown to provoke the generation of more ordered crystalline structure, adding another layer of complexity in obtaining foams with the desired density.

静态间歇发泡用于模型研究中，旨在了解和预测树脂分子结构对聚丙烯无规共聚物（RCP）在珠粒泡沫应用中发泡性的影响。乙烯含量从0到11摩尔％不等的七种聚丙烯基树脂的发泡行为可根据其各自的区域缺陷程度分为两类：低于0.1和约0.66 mol％。将乙烯含量从0增加到4.04mol％足以将泡沫密度降低6.3倍，并将发泡温度降低15℃。对于特定数量的立体和区域缺陷，乙烯含量在最佳发泡温度下具有线性响应。区域缺陷影响表现出相似的线性行为。但是，它与乙烯含量的影响脱钩。然后绘制多结晶度和泡沫机理之间的等级关系。泡沫细胞生长引起的应力被证明可以激发更有序的晶体结构，在获得具有所需密度的泡沫时又增加了另一层复杂性。