Photocalorimetric monitoring of the polymerization of an oligo(ethylene glycol) dimethacrylate in oligo(ethylene glycol) dimethyl ethers

The course of the 2,4,6-trimethylbenzoyldiphenylphosphine oxide initiated free-radical photopolymerization of an oligo(ethylene glycol) dimethacrylate ((EG)(23)DMA) in two oligo(ethylene glycol) dimethyl ethers ((EG)(3)DME and (EG)(11)DME) in the presence of LiCF3SO3 has been studied by means of differential scanning calorimetry (DSC), FT-Raman spectroscopy and sol-gel analysis. In order to obtain the kinetical data of the fast photopolymerization, the photo-DSC curves were corrected numerically. Both, the initial and the maximum polymerization rates were found to depend on the concentration of the monomer and the photo-initiator with the order 2,5 and 0,2, respectively. Upon addition of LiCF3SO3, the polymerization rate is increased. Grafting reactions from (EG)(11)DME were observed resulting in its partially linking to the poly(methacrylate) network.