Hierarchy Crystallization Structure of a Polypropylene Random Copolymer Injection-Molded Bar Induced by a Nucleating Agent
Hierarchy Crystallization Structure of a Polypropylene Random Copolymer Injection-Molded Bar Induced by a Nucleating Agent
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DOI：
10.1002/app.27121
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发表时间：
2008-01
影响因子：
3
通讯作者：
Yong Wang;Yao Gao;Jing Shi
中科院分区：
文献类型：
--
作者：
Yong Wang;Yao Gao;Jing Shi
本文研究了成核剂对聚丙烯无规共聚物（PPR）与山梨醇衍生物[1，2，3，4-二亚苄基山梨醇（DBS）]注塑棒材结晶结构的影响。结果表明，纯PPR形成了简单的皮芯结晶结构。然而，PPR/DBS形成了一个有趣而复杂的分层结晶结构：在皮层和芯区之间存在一个过渡层。在这个过渡层中，结晶结构由一些完整的球晶和许多微小的微晶组成。进一步的研究表明，多级结晶结构的形成不仅与成核剂在PPR基体中的含量有关，还与注塑成型过程中的模具温度有关。采用偏光显微镜和差示扫描量热法研究了PPR/DBS在降温过程中的结晶行为。结果表明，PPR/DBS的结晶过程存在不同的机理。在一定条件下形成的立体DBS网络可能是复杂的层次结晶结构的主要原因。© 2007 Wiley Periodicals，Inc.应用聚合物科学杂志，2008年
In this work, the effect of a nucleating agent on the crystallization structure of an injection-molded bar of a polypropylene random copolymer (PPR) with sorbitol derivatives [1,2,3,4-dibenzylidene sorbitol (DBS)] has been studied. The results show that pure PPR forms a simple skin–core crystallization structure. However, PPR/DBS forms an interesting and complicated hierarchy crystallization structure: there is a transition layer between the skin layer and the core zone. In this transition layer, the crystallization structure consists of some perfect spherulites and many tiny crystallites. Further research suggests that the formation of the hierarchy crystallization structure depends on not only the content of the nucleating agent in the PPR matrix but also the mold temperature during the injection-molding processing. The crystallization behavior of PPR/DBS during the cooling process has been characterized with polarization optical microscopy and differential scanning calorimetry. The results suggest that there are different mechanisms in the crystallization process of PPR/DBS. The formation of a three-dimensional DBS network under a certain condition might be the main reason for the complicated hierarchy crystallization structure. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008