Hybrids photoinitiators based on photoactive molecules covalently attached into nanostructured matrix are very promising for technological applications. While the focus of most efforts in this direction is on organomodified clays prepared by intercalation of quaternary ammonium compounds, in this work we describe the synthesis of a novel organic-inorganic hybrid photoinitiator based on Laponite and thioxanthone derivative (LapMTX). Its structure was characterized using 13C and 29Si NMR, FTIR experiments.  Spectroscopic properties were explored by UV−vis diffuse reflectance spectroscopy (DR) and different fluorescence techniques. LapMTX showed absorption at 392 nm and the fluorescence measurements showed an emitting state with lifetimes of 0.66 ns in DMSO. The efficiency of LapMTX as a hybrid photoinitiator was checked by photopolymerization kinetics of PEGDA. Photocalorimetry experiments (photo-DSC) showed that the increasing of the concentration of LapMTX photoinitiator increases the photopolymerization rates up to 0.5 wt%. Above 0.5 wt% of LapMTX the photopolymerization rate seemed to decrease due to a greater concentration of clay-based additives can scatter/absorb the incident light. These findings make our photoinitiator very promising candidate when it comes to radical polymerization reactions.

Covalently bonded thioxanthone-laponite hybrid as photoinitiator for polymerization

254th National Meeting (2017)

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