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本文回顾了在羰基引发剂的作用下烯烃单体光引发聚合的最新机理。报道了有关多种当前通用的新型羰基引发剂的光物理和光化学的近期工作,其中包括 UV 吸收,发光光谱和闪光光解的研究。还报道了油溶性引发剂对丙烯酸丁酯的光聚合效应。证明油溶性引发剂实质上是经过三重态来起作用,其中包含一个从溶剂中攫取氢的引发步骤。对于硫杂蒽酮衍生物来说,它们从叔胺接受电子的能力及其光聚合效应之间有一定的关系。从闪光光解获得的证据说明在这种情况下存在着自由基阴离子,但是基于二苯酮和苯基酮的引发剂则没有。预料后者直接从胺攫氢是通过三重态羰基或是引发剂的自由基。有证据表明联苯甲酰主要是通过光裂解来起作用。水溶性硫杂蒽酮引发剂的作用主要是经过单重态,其中包含引发时攫氢一步。在这种情况下,自由基的形成不受氧的影响。
This paper reviews the recent mechanism of photoinitiated polymerization of olefin monomers under the influence of carbonyl initiators. Recent work on the photophysical and photochemical properties of many of the currently used novel carbonyl initiators, including UV absorption, luminescence and flash photolysis, has been reported. The photopolymerization effect of oil-soluble initiator on butyl acrylate was also reported. It has been demonstrated that oil-soluble initiators function essentially through the triplet state and include an initiation step to grab hydrogen from the solvent. For thioxanthone derivatives, their ability to accept electrons from tertiary amines and their photopolymerization effects have some relationship. Evidence obtained from flash photolysis shows that there are free radical anions in this case, but no benzophenone- and phenylketone-based initiators. It is expected that the latter will seize hydrogen directly from amines through free radicals through the triplet carbonyls or initiators. There is evidence that dibenzoyl functions mainly through photolysis. The main role of water-soluble thioxanthone initiators is to go through a singlet state, which involves taking one step off of the hydrogen at the initiation. In this case, the formation of free radicals is not affected by oxygen.