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Polyethylene crosslinking using the epoxy-anhydride reaction I: A strategy for a curing process with high thermal sensitivity
Journal of Physical Organic Chemistry ( IF 1.9 ) Pub Date : 2022-07-29 , DOI: 10.1002/poc.4414
Kevin Lawry 1 , Varinia Bernales 1 , Jeffrey Cogen 2 , Daniel Davies 1 , Kyoungmoo Koh 3 , John Kramer 1 , Dakai Ren 4 , Mark Rickard 5 , Tanya Singh‐Rachford 6 , Yabin Sun 3 , Thomas Peterson 1
Affiliation  

The initiated epoxy-anhydride reaction was examined as a crosslink motif for effecting cure in functionalized polyethylene for electrical cable insulation applications. A specific challenge for this application is that little to no crosslinking can occur during the processing steps (~140°C), but crosslinking must be rapid and complete within a few minutes during the curing process (~200°C). To achieve this, we coupled the kinetics of the formation of an initiator for the epoxy-anhydride reaction to the crosslinking step to achieve a phenomenological temperature sensitivity or “latency” that would be difficult to access via a single simple reaction. Evaluations of different imidazolium and phosphonium salts as initiator precursors were conducted with model compounds in solution, and specific salts were chosen for polymer studies based on the ratio of the phenomenological rates measured for the model reaction at ~140°C and ~200°C. In polymer studies using epoxide-functional poly(ethylene), high crosslinking rates were observed at ~200°C while crosslinking was minimal at ~140°C. However, inclusion of the anhydride-functional polyethylene in the formulation led to loss of initiator latency, and significant crosslinking was observed at ~140°C. A reaction between the anhydride or an impurity and initiator precursor is postulated to produce a kinetically-competent initiator at lower temperatures that destroys latency.

中文翻译:

使用环氧酸酐反应的聚乙烯交联 I:具有高热敏感性的固化工艺策略

将引发的环氧酸酐反应作为交联基序在用于电缆绝缘应用的官能化聚乙烯中进行固化检查。该应用的一个具体挑战是在加工步骤(~140°C)期间几乎不会发生交联,但在固化过程(~200°C)期间,交联必须在几分钟内快速完成。为了实现这一点,我们将环氧酐反应引发剂的形成动力学与交联步骤相结合,以实现通过单个简单反应难以获得的现象学温度敏感性或“潜伏期”。使用溶液中的模型化合物对不同的咪唑鎓盐和鏻盐作为引发剂前体进行了评估,并且基于在~140°C和~200°C下为模型反应测量的现象学速率的比率选择特定的盐用于聚合物研究。在使用环氧化物官能化聚(乙烯)的聚合物研究中,在 ~200°C 时观察到高交联速率,而在 ~140°C 时交联率最低。然而,在配方中加入酸酐官能聚乙烯会导致引发剂潜伏期的损失,并且在 ~140°C 时观察到显着的交联。假定酸酐或杂质与引发剂前体之间的反应在较低温度下产生具有动力学能力的引发剂,从而破坏潜伏期。在 ~200°C 时观察到高交联率,而在 ~140°C 时交联率最低。然而,在配方中加入酸酐官能聚乙烯会导致引发剂潜伏期的损失,并且在 ~140°C 时观察到显着的交联。假定酸酐或杂质与引发剂前体之间的反应在较低温度下产生具有动力学能力的引发剂,从而破坏潜伏期。在 ~200°C 时观察到高交联率,而在 ~140°C 时交联率最低。然而,在配方中加入酸酐官能聚乙烯会导致引发剂潜伏期的损失,并且在 ~140°C 时观察到显着的交联。假定酸酐或杂质与引发剂前体之间的反应在较低温度下产生具有动力学能力的引发剂,从而破坏潜伏期。
更新日期:2022-07-29
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