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Orange is the new white: rapid curing of an ethylene-glycidyl methacrylate copolymer with a Ti-bisphenolate type catalyst†
Polymer Chemistry ( IF 4.1 ) Pub Date : 2018-01-09 00:00:00 , DOI: 10.1039/c7py01840a Massimiliano Mauri 1, 2, 3, 4 , Leo Svenningsson 1, 2, 3, 4 , Thomas Hjertberg 4, 5, 6, 7 , Lars Nordstierna 1, 2, 3, 4 , Oscar Prieto 4, 5, 6, 7 , Christian Müller 1, 2, 3, 4
Polymer Chemistry ( IF 4.1 ) Pub Date : 2018-01-09 00:00:00 , DOI: 10.1039/c7py01840a Massimiliano Mauri 1, 2, 3, 4 , Leo Svenningsson 1, 2, 3, 4 , Thomas Hjertberg 4, 5, 6, 7 , Lars Nordstierna 1, 2, 3, 4 , Oscar Prieto 4, 5, 6, 7 , Christian Müller 1, 2, 3, 4
Affiliation
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Polyethylene must be crosslinked if the polymer is to be used at elevated temperatures. However, established crosslinking methods result in the release of volatile by-products that can compromise the cleanliness and purity required for many electrical and medical applications. Currently available alternative curing processes, free from by-product formation, are too slow to be of practical relevance. Here, we demonstrate that an epoxy-bearing polyethylene copolymer, which contains one glycidyl methacrylate comonomer per 64 ethylene monomers, can be rapidly crosslinked with a click-chemistry curing process. We show that a titanium-based Lewis acid together with a bisphenol crosslinking agent allows the formation of thermosets. Compounding of the Lewis acid catalyst, crosslinking agent and copolymer through extrusion at 140 °C can be carried out without onset of the curing reaction. Then, at more elevated temperatures of 180 °C and above rapid crosslinking occurs. The competitive curing rate of the here explored formulation is due to in situ generation of a new titanium-phenoxide catalyst, which efficiently promotes crosslinking of the epoxy-bearing polyethylene copolymer. Adjustment of the curing time and temperature results in a high network density of at least 3 crosslinks per 1000 carbons in only 2 minutes at 240 °C and at a curing agent stoichiometry of 3 wt%, which corresponds to merely 0.04 wt% elemental titanium. The here established crosslinking chemistry opens up a by-product free method for rapid curing of epoxy-functionalised polyethylenes.
中文翻译：
橙色是新的白色：用双酚钛型催化剂快速固化乙烯-甲基丙烯酸缩水甘油酯共聚物†
如果要在高温下使用聚合物，则聚乙烯必须交联。但是，已建立的交联方法会释放挥发性副产物，这会损害许多电气和医疗应用所需的清洁度和纯度。目前可获得的没有副产物形成的替代固化方法太慢，以至于没有实际意义。在这里，我们证明了含环氧基的聚乙烯共聚物，其中每64个乙烯单体包含一个甲基丙烯酸缩水甘油酯共聚单体，可以通过点击化学固化工艺快速交联。我们表明，钛基路易斯酸与双酚交联剂一起可以形成热固性材料。路易斯酸催化剂的配混，交联剂和共聚物通过在140°C下挤出可以进行，而不会发生固化反应。然后，在180℃和更高的更高温度下，发生快速交联。此处探索的配方具有竞争力的固化速度归因于原位生成新钛酚盐催化剂，其有效地促进交联环氧-轴承聚乙烯共聚物的。调节固化时间和温度会导致在240°C且固化剂化学计量为3 wt％（仅相当于0.04 wt％的元素钛）的情况下，仅在2分钟内每1000个碳原子至少具有3个交联键的高网络密度。此处建立的交联化学为快速固化环氧官能化的聚乙烯开辟了无副产品的方法。
更新日期：2018-01-09
中文翻译：
橙色是新的白色：用双酚钛型催化剂快速固化乙烯-甲基丙烯酸缩水甘油酯共聚物†
如果要在高温下使用聚合物，则聚乙烯必须交联。但是，已建立的交联方法会释放挥发性副产物，这会损害许多电气和医疗应用所需的清洁度和纯度。目前可获得的没有副产物形成的替代固化方法太慢，以至于没有实际意义。在这里，我们证明了含环氧基的聚乙烯共聚物，其中每64个乙烯单体包含一个甲基丙烯酸缩水甘油酯共聚单体，可以通过点击化学固化工艺快速交联。我们表明，钛基路易斯酸与双酚交联剂一起可以形成热固性材料。路易斯酸催化剂的配混，交联剂和共聚物通过在140°C下挤出可以进行，而不会发生固化反应。然后，在180℃和更高的更高温度下，发生快速交联。此处探索的配方具有竞争力的固化速度归因于原位生成新钛酚盐催化剂，其有效地促进交联环氧-轴承聚乙烯共聚物的。调节固化时间和温度会导致在240°C且固化剂化学计量为3 wt％（仅相当于0.04 wt％的元素钛）的情况下，仅在2分钟内每1000个碳原子至少具有3个交联键的高网络密度。此处建立的交联化学为快速固化环氧官能化的聚乙烯开辟了无副产品的方法。
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