Deformation Temperature Dependency of Microstructure Evolution in Die-Drawn iPP/UHMWPE Blends

IF 5.2 1区化学 Q1 POLYMER SCIENCE

Macromolecules Pub Date : 2024-09-23 DOI:10.1021/acs.macromol.4c01650

Xuan Qin, Ying Lu, Dong Lyu, Fin Caton-Rose, Phil Coates, Yongfeng Men

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Abstract

Ultrahigh molecular weight polyethylene (UHMWPE) is one of the most promising polyolefins, but its processability and consequently applications are limited by its high melt viscosity. An effective method to improve the processability is to introduce another polymer component. Yet it is challenging to deform the sample if the components are not compatible with each other. In this work, we blended the UHMWPE with isotactic polypropylene (iPP) and successfully processed the iPP/UHMWPE samples via die-drawing at temperatures below, near, and above the melting temperature of UHMWPE. It was found that the melting behavior of the die-drawn samples was determined by the deformation temperature. The molecular chain orientation slightly decreased, while the long periods first increased and then decreased with increasing deformation temperature. Three melting peaks observed in the samples deformed at 130 and 140 °C originated from the melting of cooling-induced UHMWPE crystallites, deformation-induced fibrillar UHMWPE crystallites, and deformation-induced fibrillar iPP crystallites, respectively. The melting peak of deformation-induced fibrillar UHMWPE crystallites could not be observed in the sample deformed at 150 °C because it is unlikely for UHMWPE chains to crystallize at such a high temperature. This sample also has the lowest melting point since the UHMWPE lamellae formed during deformation could serve as nucleation sites in the other two samples.

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模压拉伸 iPP/UHMWPE 混合物微观结构演变的变形温度依赖性

超高分子量聚乙烯（UHMWPE）是最有前途的聚烯烃之一，但由于其熔体粘度较高，其加工性和应用受到限制。改善加工性能的有效方法是引入另一种聚合物成分。然而，如果各组分之间不兼容，要使样品变形就很困难。在这项工作中，我们将超高分子量聚乙烯与异方根聚丙烯（iPP）混合，并在低于、接近和高于超高分子量聚乙烯熔化温度的条件下，通过模头拉伸成功加工了 iPP/UHMWPE 样品。研究发现，压模拉伸样品的熔化行为由变形温度决定。随着变形温度的升高，分子链取向略有减小，而长周期先增加后减小。在 130 和 140 °C 变形温度下观察到的三个熔化峰分别来自冷却诱导的超高分子量聚乙烯结晶、变形诱导的纤维状超高分子量聚乙烯结晶和变形诱导的纤维状 iPP 结晶的熔化。由于超高分子量聚乙烯链不可能在如此高的温度下结晶，因此在 150 °C 变形的样品中无法观察到变形诱导的纤维状超高分子量聚乙烯结晶的熔化峰。该样品的熔点也是最低的，因为在变形过程中形成的超高分子量聚乙烯薄片可作为其他两个样品的成核点。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Macromolecules 工程技术-高分子科学

CiteScore

9.30

自引率

16.40%

发文量

942

审稿时长

2 months

期刊介绍： Macromolecules publishes original, fundamental, and impactful research on all aspects of polymer science. Topics of interest include synthesis (e.g., controlled polymerizations, polymerization catalysis, post polymerization modification, new monomer structures and polymer architectures, and polymerization mechanisms/kinetics analysis); phase behavior, thermodynamics, dynamic, and ordering/disordering phenomena (e.g., self-assembly, gelation, crystallization, solution/melt/solid-state characteristics); structure and properties (e.g., mechanical and rheological properties, surface/interfacial characteristics, electronic and transport properties); new state of the art characterization (e.g., spectroscopy, scattering, microscopy, rheology), simulation (e.g., Monte Carlo, molecular dynamics, multi-scale/coarse-grained modeling), and theoretical methods. Renewable/sustainable polymers, polymer networks, responsive polymers, electro-, magneto- and opto-active macromolecules, inorganic polymers, charge-transporting polymers (ion-containing, semiconducting, and conducting), nanostructured polymers, and polymer composites are also of interest. Typical papers published in Macromolecules showcase important and innovative concepts, experimental methods/observations, and theoretical/computational approaches that demonstrate a fundamental advance in the understanding of polymers.