Journal of Polymer Science Part A: Polymer Chemistry, Vol.36, No.15, 2775-2783, 1998
Kinetic investigations on the photopolymerization of Di- and tetrafunctional (meth)acrylic monomers in polymeric matrices. ESR and calorimetric studies. 1. Reactions under irradiation
The photopolymerization of several di- and tetrafunctional (meth)acrylic monomers in the presence of a styrene-butadiene-styrene polymeric matrix (SBS) has been studied. Electron spin resonance spectroscopy (ESR) and differential scanning photocalorimetry (photo-DSC) were used as monitoring techniques to identify the photogenerated radicals and analyze photopolymerization profiles, radical environments, and radical secondary reactions. The study of the photopolymerization and/or photocrosslinking reactions of these monomers in the solid media was carried out by taking into consideration different factors, such as the influence of both monomer and photoinitiator structures on the hydrogen abstraction in the binder with formation of benzylic and allylic radicals, the polymerization of the monomers itself and the hydrogen abstraction reaction in the polymerized acrylic chains. Finally, irradiation of the system SBS/photoinitiator in the absence of monomer was also accomplished.
Keywords:FREE-RADICAL COPOLYMERIZATION, MOLECULAR-WEIGHT CALCULATIONS;ELECTRON-SPIN-RESONANCE, RATE-CONSTANT METHOD, CROSS-LINKING;METHACRYLATE MONOMERS, GRAFTING REACTIONS, EMULSIONPOLYMERIZATION, NETWORK FORMATION, TRAPPED RADICALS