Abstract Currently cationic photoinitiators possess undesirable characteristics of poor solubility in epoxy resins and the release of odorous and toxic by-products. These shortcomings greatly limit the applications of the photoinitiators. Here, the synthesis and initiating cationic photopolymerization properties of three new polysiloxane-modified 5-arylthianthrenium salt cationic photoinitiators (1187-Si-A/B/C) whose polysiloxane-modified cations could be considered as environmentally friendly are reported. The photoinitiators are synthesized based on 9-(4-hydroxyethoxyphenyl) thianthrenium hexaflorophosphate (Esacure 1187) and polysiloxane. The cationic photoinitiators not only exhibit excellent solubility in epoxy resins, but also do not release odour and toxic by-products under UV irradiation, which is demonstrated by liquid chromatography-electrospray ionization-mass spectrometry [LC-ESI(+)-MS]. The photoinitiating activity of 1187-Si-A/B/C is investigated by real-time infrared spectroscopy (RTIR), and it is found that 1187-Si-A/B/C can effectively initiate cationic photopolymerization by the photosensitization of 9,10-dibutoxyanthracene (DBA). More importantly, the polysiloxane chains offer 1187-Si-A/B/C good self-floating capability, and thus the photoinitiators are promising for the preparation of gradient polymers by cationic photopolymerization.

中文翻译：

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具有自漂浮能力的聚硅氧烷改性5-芳基铪盐阳离子光引发剂的合成及性能

摘要 目前，阳离子光引发剂具有在环氧树脂中溶解度差和释放有气味和有毒副产物的不良特性。这些缺点极大地限制了光引发剂的应用。在这里，报道了三种新的聚硅氧烷改性的 5-芳基铪盐阳离子光引发剂 (1187-Si-A/B/C) 的合成和引发阳离子光聚合性能，其聚硅氧烷改性的阳离子可以被认为是环境友好的。光引发剂是基于 9-(4-羟基乙氧基苯基) 六氟磷酸铪 (Esacure 1187) 和聚硅氧烷合成的。阳离子光引发剂不仅在环氧树脂中表现出优异的溶解性，而且在紫外线照射下不释放气味和有毒副产物，液相色谱-电喷雾电离-质谱 [LC-ESI(+)-MS] 证明了这一点。通过实时红外光谱(RTIR)研究了1187-Si-A/B/C的光引发活性，发现1187-Si-A/B/C可以通过9的光敏化有效引发阳离子光聚合， 10-二丁氧基蒽 (DBA)。更重要的是，聚硅氧烷链提供了 1187-Si-A/B/C 良好的自漂浮能力，因此光引发剂有望用于通过阳离子光聚合制备梯度聚合物。10-二丁氧基蒽 (DBA)。更重要的是，聚硅氧烷链提供了 1187-Si-A/B/C 良好的自漂浮能力，因此光引发剂有望用于通过阳离子光聚合制备梯度聚合物。10-二丁氧基蒽 (DBA)。更重要的是，聚硅氧烷链提供了 1187-Si-A/B/C 良好的自漂浮能力，因此光引发剂有望用于通过阳离子光聚合制备梯度聚合物。