A novel thermally latent anionic initiator. Polymerization of epoxide with hydroxylamide based on thermal dissociation
A novel thermally latent anionic initiator. Polymerization of epoxide with hydroxylamide based on thermal dissociation
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一种新型热潜阴离子引发剂。
DOI：
10.1021/ma0257292
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发表时间：
2003
期刊：
影响因子：
5.5
通讯作者：
T. Endo
中科院分区：
文献类型：
--
作者：
F. Sanda;Tomoyoshi Kaizuka;and Atsushi Sudo;T. Endo
潜伏引发剂在正常条件下不显示活性，但通过外部刺激如加热和光照射释放活性物质以引发聚合。它们已被广泛应用于油漆、油墨、环氧模塑化合物和光致抗蚀剂。已经开发了几种鎓盐如锍、吡啶鎓、鏻盐1和二芳基碘鎓和三芳基锍盐2作为热潜引发剂和/或光引发剂。然而，鎓盐在单体和溶剂中的溶解度低，成本高，并且无机化合物在聚合物中残留，这导致毒性和产品性能如绝缘性的降低。已经通过开发非盐型引发剂进行了相当大的努力来克服这些问题。3我们已经证明，N-取代邻苯二甲酰亚胺，4氨基酰亚胺，5羧酸酯，6和磺酸酯7作为非盐型潜在引发剂的环氧化物聚合。最近，我们已经报道了膦酰胺酯在缩水甘油基苯基醚（GPE）的聚合中也用作热潜阴离子引发剂，其中活性物质是通过消除异丁烯随后与GPE连续反应并形成释放胺的环酰胺酯而从膦酰胺酯释放的胺（方案1）。8该引发剂体系的关键点是酰胺-酯交换反应，通过形成稳定的环状化合物释放胺，尽管羟基的亲核性小于胺的亲核性。利用酰胺基与羟基的分子内反应，有望开发出一种新型的潜伏性引发剂。介绍了一种基于酰胺-酯交换反应伴随热分解的新型简单热潜伏引发剂体系。根据与文献类似的方式，分别通过哌啶与γ-丁内酯和苯酞在室温下反应过夜来合成羟基酰胺1a和1b（方案2）。9它们作为无色油状物（1a）和固体获得
Latent initiators show no activity under normal conditions but release active species by external stimulation such as heating and photoirradiation to initiate polymerization. They have been widely applied to paints, inks, epoxy molding compounds, and photoresists. Several onium salts like sulfonium, pyridinium, phosphonium salts, 1 and diaryliodonium and triarylsulfonium salts2 have been developed as thermally latent initiators and/or photoinitiators. However, onium salts suffer low solubility in monomers and solvents, high cost, and residue of inorganic compounds in polymers, which causes toxicity and lowering of product properties such as insulation. Considerable efforts have been made to overcome these problems by developing non-salt-type initiators. 3 We have demonstrated that N-substituted phthalimides, 4 aminimides, 5 carboxylic acid esters, 6 and sulfonic acid esters7 serve as non-salttype latent initiators for epoxide polymerization. Recently, we have reported that phosphonic amide esters also serve as thermally latent anionic initiators in the polymerization of glycidy phenyl ether (GPE), wherein the active species is an amine released from the phosphonic amide esters by elimination of isobutene followed by successive reaction with GPE and formation of a cyclic amide ester releasing the amine (Scheme 1). 8 The key point of this initiator system is amide-ester exchange reaction releasing the amine by formation of a stable cyclic compound, although the nucleophilicity of the hydroxyl group is smaller than that of the amine. It may be expected that utilization of intramolecular reaction between amide and hydroxyl groups enables us to develop a new latent initiator. This paper communicates a novel simple thermally latent initiator system based on the thermal dissociation accompanying amide-ester exchange reaction. Hydroxylamides 1a and 1b were synthesized by the reaction of piperidine with γ-butyrolactone and phthalide at room temperature overnight according to a manner similar to the literature, respectively (Scheme 2). 9 They were obtained as a colorless oil (1a) and solid