New Coupling Agent Structures for Preparing Filler-Polymer Hybrid Materials Under Soft Irradiation Conditions

International audienceThe bifunctional coupling agents have become unavoidable products for preparing hybrid materials with enhanced properties. They are at the origin of the homogeneous dispersion of the filler in the polymerizable matrix and the strong chemical interactions between the composites during the thermal reticulation and vulcanization processes. However, only few structures can play this role in a photo-curable matrix, which is widely applied today in various manufactures (3D printing, cosmetic, medicine, etc.). Developing new structures capable of working under accurate irradiation conditions can extend the use of coupling agents for preparing hybrid photo-curable materials for various applications (e.g. membrane, masks, 2D- and 3D- nano/micro-objects). Recently, a new SPI (SPI-1) was proposed by our group and has revealed a high efficiency for preparing filler-polymer hybrid material. Despite its efficiency, its activity is the highest under the UV-B irradiation but lower under UV-A and inactive under visible light. In this paper, new coupling agent structures (bifunctional Silane-based Photoinitiators; SPI) are synthesized and tested under various irradiation conditions extensively used in the photocuring fields (365, 385 and 405 nm). All the new structures demonstrate higher performance than the first SPI generation (SPI-1) under the diverse light sources. More particularly, SPI-4, 5, and 6 (triphenylamine-based SPI) demonstrate a remarkable activity for preparing filler-polymer hybrid materials under visible light irradiation (LED 405 nm). The efficiency of the new structures in the photopolymerization as well as in the grafting of the silica particles (used as filler model) is elucidated. Finally, the enhancement of the mechanical properties of the hybrid composite films and the possible use of the new approach in photolithography is also demonstrated