Study on Photolysis of Polymers and Surfactants Containing Benzyl Groups

由于废旧塑料的紧急处理，光降解聚合物受到了广泛的关注。在本研究中，探索紫外光降解聚合物材料，一系列的萘甲基和苄基xanthethacrylate聚合物和它们的单体模型化合物的制备和它们的光反应性进行了研究，在溶液和流延膜。在模型化合物中引入α-甲基取代基降低了它们的光解效率，改变了产物分布，这可能主要是由于酯键周围的空间位阻。甲基丙烯酸萘甲酯聚合物中的酯键断裂也表现出取代基依赖性，但主链断裂几乎没有发生，特别是在流延膜中。相反，在甲基丙烯酸苄酯聚合物中，酯键断裂较少依赖于取代基，而主链断裂有效地发生，这在甲基丙烯酸酯聚合物中比在丙烯酸酯聚合物中更有效。这种光反应性的差异不仅反映了单体单元的空间位阻，而且还反映了聚合物主链中形成的自由基的稳定性。研究还发现，阳离子表面活性剂和含苄基铵基团的聚电解质会引起某些芳香族化合物在水溶液中的光诱导分解。这些材料将用于分解和去除废水中的有机污染物。这些应用研究正在进行中。

Much attention has been paid to photodegradative polymers because of emergent disposal of waste plastics. In the present study, to explore the UV-photodegradative polymeric materials, a series of naphthylmethyl- and benzyl-xnethacrylate polymers and their monomeric model compounds were prepared and their photoreactivity was examined in solution and cast films. Introduction of alpha-methyl substituents into the model compounds decreased their photolysis efficiencies and altered the product distribution, which may be mainly due to steric hindrance around the ester bond. The ester bond cleavage in naphthylmethylmethacrylate polymers also showed substituent-dependent, but the main-chain scission scarcely occurred, in particular in cast films. In benzylmethacrylate polymers, in contrast, the ester bond cleavage was less substituent dependent, while the main-chain scission occurred efficiently, which was more effective in methacrylate polymers than in acrylate ones. Such differences in the photoreactivity reflect not only the steric hindrance of the monomer units but also the stability of radicals formed in the polymer main chain. It was also found that cationic surfactants and polyelectrolytes containing benzylammonium groups caused photoinduced decomposition of some aromatic compounds in aqueous solution. These materials would be useful for decomposition and removal of organic pollutants in waste water. Such applied studies are in progress.