Revealing toughening mechanism for alternating multilayered polypropylene/poly(ethylene-co-octene) sheets
Revealing toughening mechanism for alternating multilayered polypropylene/poly(ethylene-co-octene) sheets
复制标题
揭示交替多层聚丙烯/聚（乙烯-共辛烯）片材的增韧机制
DOI：
10.1016/j.polymertesting.2014.12.006
复制
发表时间：
2015-02-01
期刊：
影响因子：
5.1
通讯作者：
Huang, Han-Xiong
中科院分区：
文献类型：
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作者：
Li, Wei-Ping;Huang, Han-Xiong
采用多层共挤法制备了交替多层（16层、32层和128层）聚丙烯/聚乙烯-共辛烯（PP/POE）板材。对制备的多层样品进行了冲击（-20℃）、拉伸和动态流变试验。通过对多层试样断口形貌的研究和断口功的分析，揭示了多层试样的增韧机理。结果表明：有缺口的多层试样由于空化作用，冲击能主要被连续薄韧性POE层吸收，而无缺口的多层试样由于PP层和POE层存在多重裂纹、开裂和明显的塑性变形，对断裂总功都有显著贡献，从而显著延长了裂纹扩展路径。因此，多层样品的非缺口冲击强度比缺口冲击强度高得多。随着层数的增加，多层样品的缺口冲击强度略有增加，而非缺口冲击强度明显增加。有趣的是，多层样品的缺口灵敏度低于PP样品。在低温冲击韧性显著提高的同时，多层材料的强度和刚度均保持在PP材料的基础上，且具有较好的延伸性。(C) 2014 Elsevier Ltd.版权所有。
Alternating multilayered (16, 32, and 128 layers) polypropylene/poly(ethylene-co-octene) (PP/POE) sheets were prepared via multilayer co-extrusion. Impact (-20 degrees C), tensile, and dynamic rheological tests were carried out on the prepared multilayered samples. The toughening mechanism for the multilayered samples was revealed via investigating their fracture surface morphology and analyzing the work of fracture. The results showed that the impact energy for the notched multilayered samples is mainly absorbed by the continuous thin ductile POE layers due to cavitation, whereas for the unnotched multilayered samples the continuous thin POE and PP layers both contributed significantly to the total work of fracture due to multiple crazing, cracking and distinct plastic deformation in both PP and POE layers, and thus significantly extended crack propagation paths. Hence, the multilayered samples possessed much higher unnotched impact strength than notched impact strength. Moreover, the multilayered samples exhibited slightly increased notched impact strength and obviously increased unnotched impact strength with increasing layer number. Interestingly, the multilayered samples exhibited lower notch sensitivity than the PP sample. In addition to significantly improved low temperature impact toughness, the multilayered samples maintained the strength and stiffness as well as having superior extensibility to that of the PP sample. (C) 2014 Elsevier Ltd. All rights reserved.