Gao Tong, Liu Zheng, Feng Ji, Dietlin Céline, Morlet-Savary Fabrice, Zhang Jing, Shan Wenpeng, Dumur Frédéric, Xiao Pu, Lalevée Jacques
Université de Haute-Alsace, CNRS, IS2M UMR7361, F-68100 Mulhouse, France.
Université de Strasbourg, F-67000 Strasbourg, France.
ACS Appl Mater Interfaces. 2024 Dec 18;16(50):69984-69998. doi: 10.1021/acsami.4c18660. Epub 2024 Dec 4.
In this work, we introduce twenty-six phenothiazine derivatives (PTZs) that were designed and synthesized as visible light photoinitiators. These compounds, in combination with an amine [ethyl 4-(dimethylamino)benzoate (EDB)] and an iodonium salt [di--butylphenyl iodonium hexafluorophosphate (Iod)], could furnish high-performance three-component (PTZs/EDB/Iod) photoinitiating systems that were employed for the free radical polymerization of thick films of a low-viscosity model acrylate resin, namely, trimethylolpropane triacrylate (TMPTA) under visible light and sunlight exposure. A commercial thioxanthone, i.e., isopropylthioxanthone (ITX) was selected to design a reference ITX/EDB/Iod photoinitiating system. Double bond conversions of 87% and 76% were measured for the developed and synthesized photoinitiating systems under 405 and 450 nm light-emitting diode irradiation, respectively, and a conversion as high as 70% could be determined under sunlight irradiation─about 23 times higher than the conversion obtained with the comparable system prepared with the commercial photoinitiator. The relevant photoinitiation abilities and photochemical mechanisms are comprehensively investigated by a combination of techniques including real-time Fourier transform infrared spectroscopy, UV-visible absorption spectroscopy, fluorescence spectroscopy, steady-state photolysis, cyclic voltammetry, and electron paramagnetic resonance. Notably, the exceptional performance of the photoinitiators enabled the fabrication of 3D objects with precise morphology and superior resolution through 3D printing and direct laser write techniques. These findings not only provide opportunities for efficient polymerization under artificial and natural light conditions but also pave the way for scalable, cost-effective, environmentally sustainable, and green chemistry-driven curing applications.
在本研究中，我们介绍了二十六个作为可见光光引发剂设计合成的吩噻嗪衍生物（PTZs）。这些化合物与一种胺[4-(二甲基氨基)苯甲酸乙酯（EDB）]和一种碘鎓盐[二丁基苯基六氟磷酸碘鎓（Iod）]组合，可提供高性能的三组分（PTZs/EDB/Iod）光引发体系，该体系用于低粘度模型丙烯酸酯树脂（即三羟甲基丙烷三丙烯酸酯（TMPTA））厚膜在可见光和阳光照射下的自由基聚合。选择一种商业噻吨酮，即异丙基噻吨酮（ITX）来设计参考ITX/EDB/Iod光引发体系。对于所开发和合成的光引发体系，在405和450 nm发光二极管照射下分别测得双键转化率为87%和76%，在阳光照射下转化率高达70%，这大约是使用商业光引发剂制备的可比体系所获得转化率的23倍。通过实时傅里叶变换红外光谱、紫外可见吸收光谱、荧光光谱、稳态光解、循环伏安法和电子顺磁共振等技术相结合，全面研究了相关的光引发能力和光化学机理。值得注意的是，这些光引发剂的优异性能使得通过3D打印和直接激光写入技术能够制造出具有精确形态和卓越分辨率的3D物体。这些发现不仅为在人工和自然光条件下的高效聚合提供了机会，也为可扩展、经济高效、环境可持续且由绿色化学驱动的固化应用铺平了道路。
