Toughed polypropylene (PP) foams, with the combination of blending with trans‐1,4‐polyisoprene (TPI) and micro/nanocellular structure in the matrix, were prepared using a batch foaming process and N₂ as the blowing agent. The incorporation of TPI in the PP matrix induces the enhanced formability and the slightly improved ductility and toughness compared to the neat PP. The simultaneous existence of the TPI phase and micro/nanocellular structure makes the fracture behavior follow the shear yielding of a bundle of fibrils in the tensile load direction. The results of mechanical properties measurements show that the notched Izod impact strengths of foamed PP/TPI blend are two to three times larger than those of the unfoamed counterparts. The PP/TPI blend foam with 5phr TPI content shows the highest impact strength when the foaming temperature is 140°C, which is fivefold increase over that of the neat PP. The enhanced ductility and toughness of PP/TPI foams were found with the increasing foaming temperature. The insert of micro−/nanocellular in PP/TPI blends simultaneously makes the notched impact strength increase significantly, tensile strength decrease, and elongation at break increase obviously, which provides the possibility to combine the higher impact strength and toughness with the advantage of microcellular foaming. POLYM. ENG. SCI., 60:211–217, 2020. © 2019 Society of Plastics Engineers

中文翻译：

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以超临界氮为发泡剂的微/纳米多孔聚丙烯/反式1,4-聚异戊二烯（PP / TPI）混合泡沫

使用分批发泡工艺和N ₂制备了增韧的聚丙烯（PP）泡沫，将其与反式1,4-聚异戊二烯（TPI）混合以及基质中的微/纳孔结构相结合作为发泡剂。与纯PP相比，TPI在PP基体中的引入可增强可成型性，并略微改善延展性和韧性。TPI相和微/纳米结构的同时存在使断裂行为遵循在拉伸载荷方向上一束原纤维的剪切屈服。力学性能测量结果表明，泡沫PP / TPI共混物的缺口悬臂梁式冲击强度是未发泡同类物的2至3倍。当发泡温度为140°C时，具有5phr TPI含量的PP / TPI混合泡沫显示出最高的冲击强度，是纯PP的五倍。随着发泡温度的升高，PP / TPI泡沫的延展性和韧性得到增强。在PP / TPI共混物中插入微/纳米孔同时使缺口冲击强度显着增加，拉伸强度降低，断裂伸长率明显增加，这提供了将较高的冲击强度和韧性与微孔发泡优势相结合的可能性。POLYM。ENG。SCI。，60：211–217，2020.©2019塑料工程师协会