Study on Photolysis of Polymers and Surfactants Containing Benzyl Groups

由于废塑料处理的出现，光降解聚合物受到了广泛的关注。为了探索紫外光降解高分子材料，制备了一系列甲基萘和苯乙丙烯酸酯聚合物及其单体模型化合物，并对其在溶液和铸膜中的光反应性进行了研究。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，改变了产物的分布，这可能主要是由于酯键周围的位阻。甲基丙烯酸甲酯聚合物的酯键断裂也表现为取代基依赖性，但主链断裂很少发生，特别是在铸膜中。而在甲基丙烯酸甲酯聚合物中，酯键的断裂对取代基的依赖性较弱，而主链的断裂效率较高，甲基丙烯酸甲酯聚合物的断裂效率高于丙烯酸酯聚合物。这种光反应性的差异不仅反映了单体单元的空间位阻，也反映了聚合物主链中形成的自由基的稳定性。还发现阳离子表面活性剂和含苄胺基团的聚电解质可引起水溶液中某些芳香族化合物的光致分解。这些材料可用于分解和去除废水中的有机污染物。这种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.