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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.
In order to study the reaction mechanism of the thiolene light curing composition, the photochemical properties of thioalkene were studied by infrared spectroscopy using benzoin, dimethylbenzoate, benzoin-n-butyl ether, benzophenone and thioxanthone as photosensitizers Reaction kinetics.When the concentration of photosensitizer is constant, the reaction rate is proportional to the first-order side of thiol concentration. When the concentration of photosensitizer is different, the rate constant and the concentration of photosensitizer are linear within a certain range, and the linear section Distance and slope of a linear relationship between the mercaptoethanol and the photosensitizer mixture by UV irradiation does not react.A new mechanism of thiol ene photochemical reaction --- photosensitizer molecules absorb a certain wavelength of ultraviolet light transition to the excitation Singlet and then into the excited triplet state; longer life excited triplet photosensitizer molecules will be the energy transfer to thiol molecules, so that it becomes excited triplet state, followed by attack ene bond addition reaction. The molecule returns to ground state by releasing energy and terminating the reaction.