Abstract In the underlying literature, bubble coalescence has been so far observed at the latest foaming stages, where bubble growing causes large extensional loads on the polymer film between two neighboring bubbles and eventually leads to the film rupture and to the merging of the two bubbles in a single one. This phenomenon is responsible for the coarsening of the foam morphology and, in turn, the worsening of the final foam properties. Here, the unanticipated, indirect, observation of a bubble coalescence phenomenon occurring at the very early stage of foaming, when most of the blowing agent is still solubilized in the polymer, is reported. Likewise, this phenomenon is responsible for a significant coarsening of the foam morphology. With the aim of investigating this phenomenon, a novel pressure vessel for foaming was utilized, capable of imposing two different cooling histories on two polymer samples, foamed at the same time. Results are presented on polystyrene foamed with carbon dioxide.

中文翻译：

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热塑性发泡中的早期气泡聚结

摘要 在基础文献中，到目前为止，在最新的发泡阶段已经观察到气泡聚结，其中气泡的增长导致两个相邻气泡之间的聚合物膜上产生较大的拉伸载荷，并最终导致膜破裂和两个气泡合并。一个。这种现象导致泡沫形态变粗，进而导致最终泡沫性能恶化。在这里，报告了在发泡的非常早期阶段发生的气泡聚结现象的意外的、间接的观察，此时大部分发泡剂仍溶解在聚合物中。同样，这种现象是泡沫形态显着粗化的原因。为了研究这种现象，使用了一种新型的发泡压力容器，能够对同时发泡的两个聚合物样品施加两种不同的冷却历史。结果显示在用二氧化碳发泡的聚苯乙烯上。