The dependence of the foaming behaviour of a polymeric material on its material characteristics and foaming temperature gives rise to the research question that how the degree of dispersion/distribution of nanoparticles and the resulting viscosity changes affect the foaming behaviour and properties of nanocomposite foams. In the study reported here, styrene–ethylene–butylene–styrene was selected as a model polymer, because of its complex microstructure and its commercial importance. Styrene–ethylene–butylene–styrene nanocomposites, with different nanoclay loadings, were processed in a twin-screw extruder. The nanocomposite structure was correlated with the rheological properties to evaluate the batch-foaming performance of nanocomposite using carbon dioxide at different temperatures. At 35 °C, selective foaming of the elastomeric phase, hindered by the stiff polystyrene phase, resulted in foams with more than 74% shrinkage. At 80 °C, higher viscosities and moduli resulted in foams with higher volume expansion ratios. Increases in the degree of delamination of silicate layers in nanocomposites resulted in cell sizes up to 41% and 75% lower than that of neat polymer foams produced at 35 °C and 80 °C, respectively. Dynamic mechanical analysis results suggest heterogeneous nucleation and the presence of nanoclay in both phases. The study results show that the nanocomposite structure plays an important role in the production of thermoplastic elastomer foams of superior morphology and low shrinkage. Graphical abstract

中文翻译：

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苯乙烯-乙烯-丁烯-苯乙烯纳米复合材料的流变学和发泡行为

聚合物材料的发泡行为对其材料特性和发泡温度的依赖性引起了一个研究问题，即纳米颗粒的分散/分布程度和由此产生的粘度变化如何影响纳米复合泡沫的发泡行为和性能。在这里报道的研究中，苯乙烯-乙烯-丁烯-苯乙烯被选为模型聚合物，因为它具有复杂的微观结构和商业重要性。苯乙烯-乙烯-丁烯-苯乙烯纳米复合材料，具有不同的纳米粘土负载量，在双螺杆挤出机中加工。纳米复合材料的结构与流变性能相关，以评估纳米复合材料在不同温度下使用二氧化碳的批量发泡性能。在 35 °C 时，弹性体相选择性发泡，硬聚苯乙烯相的阻碍，导致泡沫收缩率超过 74%。在 80 °C 时，更高的粘度和模量导致泡沫具有更高的体积膨胀比。纳米复合材料中硅酸盐层分层程度的增加导致泡孔尺寸分别比在 35°C 和 80°C 下生产的纯聚合物泡沫低 41% 和 75%。动态力学分析结果表明两相中均存在异质成核和纳米粘土。研究结果表明，纳米复合结构在生产具有优异形态和低收缩率的热塑性弹性体泡沫方面起着重要作用。图形概要 更高的粘度和模量导致泡沫具有更高的体积膨胀比。纳米复合材料中硅酸盐层分层程度的增加导致泡孔尺寸分别比在 35°C 和 80°C 下生产的纯聚合物泡沫低 41% 和 75%。动态力学分析结果表明两相中均存在异质成核和纳米粘土。研究结果表明，纳米复合结构在生产具有优异形态和低收缩率的热塑性弹性体泡沫方面起着重要作用。图形概要 更高的粘度和模量导致泡沫具有更高的体积膨胀比。纳米复合材料中硅酸盐层分层程度的增加导致泡孔尺寸分别比在 35°C 和 80°C 下生产的纯聚合物泡沫低 41% 和 75%。动态力学分析结果表明两相中均存在异质成核和纳米粘土。研究结果表明，纳米复合结构在生产具有优异形态和低收缩率的热塑性弹性体泡沫方面起着重要作用。图形概要 动态力学分析结果表明两相中均存在异质成核和纳米粘土。研究结果表明，纳米复合结构在生产具有优异形态和低收缩率的热塑性弹性体泡沫方面起着重要作用。图形概要 动态力学分析结果表明两相中均存在异质成核和纳米粘土。研究结果表明，纳米复合结构在生产具有优异形态和低收缩率的热塑性弹性体泡沫方面起着重要作用。图形概要