Synthesis of Disentangled Ultra-High Molecular Weight Polyethylene: Influence of Reaction Medium on Material Properties
Synthesis of Disentangled Ultra-High Molecular Weight Polyethylene: Influence of Reaction Medium on Material Properties
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DOI：
10.1155/2017/7431419
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发表时间：
2017-01-01
影响因子：
3.3
通讯作者：
Ronca, Sara
中科院分区：
文献类型：
--
作者：
Forte, Giuseppe;Ronca, Sara
在一定的反应条件下，乙烯聚合成超高分子量聚乙烯（UHMWPE），可以合成具有相当低缠结量的新生粉末：从学术和工业角度来看，所获得的材料都是非常有趣的。从学术的角度来看，随着纠缠的逐渐形成，跟踪亚稳态熔体状态的演变是很有趣的。在工业上，对于高模量、高强度胶带的生产，有一条无溶剂的加工路线是有价值的。由于聚合物的合成是在溶剂存在的情况下进行的，因此在宏观和微观水平上研究反应介质对催化剂活性、所得分子特性和聚合物形态的影响是很有趣的。本文介绍了两种典型的聚合溶剂甲苯和庚烷及其混合物对催化性能和聚合物性能的影响。观察结果是，当使用精心选择的溶剂混合物时，发现催化剂活性出乎意料地增加，伴随着机械性能的显着改善。根据所提出的结果，给出了一个尝试性的解释。
The polymerization of ethylene to Ultra-High Molecular Weight Polyethylene (UHMWPE) in certain reaction conditions allows synthesis of nascent powders with a considerably lower amount of entanglements: the material obtained is of great interest from both academic and industrial viewpoints. From an academic point of view, it is interesting to follow the evolution of the metastable melt state with the progressive entanglements formation. Industrially, it is valuable to have a solvent-free processing route for the production of high modulus, high strength tapes. Since the polymer synthesis is performed in the presence of a solvent, it is interesting to investigate the influence that the reaction medium can have on the catalyst activity, resultant molecular characteristics, and polymer morphology at the macroscopic as wells as microscopic level. In this paper, we present the effect that two typical polymerization solvents, toluene and heptane, and mixtures of them, have on the catalytic performance and on the polymer properties. The observations are that an unexpected increase of catalyst activity, accompanied by a significant improvement in mechanical properties, is found when using a carefully chosen mixture of solvents. A tentative explanation is given on the basis of the presented results.