【摘要】 为研究硫醇 烯光固化组成物的反应机理,选用安息香双甲醚、安息香乙醚、安息香正丁醚、二苯甲酮和噻吨酮为光敏剂,用红外光谱法研究了硫醇 烯的光化学反应动力学.当光敏剂浓度一定时,反应速率与硫醇浓度的一次方成正比;当光敏剂浓度不同时,速率常数与光敏剂的浓度在一定范围内呈线性关系,并且该直线的截距与斜率之间呈线性关系.由巯基乙醇和光敏剂组成的混合物受紫外光照射不发生反应.提出硫醇 烯光化学反应的新机理———光敏剂分子吸收一定波长的紫外光跃迁到激发单线态,然后转变为激发三线态;寿命较长的激发三线态光敏剂分子将能量传递给硫醇分子,使之变为激发三线态,接着进攻烯键发生加成反应.各种激发态的分子通过释放能量回到基态,使反应终止.更多还原

【Abstract】 The kinetics of thiol-ene reaction is studied by Fourier Transform Infrared when benzoin dimethyl ether, benzoin ethyl ether, benzoin butyl ether, benzophenone and ITX were used as photosensitizer. The results show that the photoinitiated thiol-ene reaction is a first-order reaction and rate constant is in linear relationship with the concentration of photosensitizer. The intercept of the diagram of the rate constant k vs photosensitizer concentration may change with the photosensitizer used differently, and it increases along the slope. But the thiol-ene admixture without photosensitizer can′t react when it is irradiated by ultraviolet.Based on the above results, a new mechanism for reaction of thiol-ene system is put forward. It is that excitation of the photosensitizer by the absorption of ultraviolet light, followed by energy transferred to thiol, inspires thiol to excited state and reacts with double bond generating excited state thiyl compound. The thiyl compound releases energy and returns to basic state.更多还原