Fractal Kinetics of Diacrylates Postcuring by Curve-fitting Real-time FTIR

摘要

Photopolymerization of multifunctional monomers is an important industrial technique for obtaining highly crosslinked polymers at room temperature,by short time irradiation with an intense UV light. Although reactive species are created during UV irradiation,a substantial part of polymerization reactions continue long after the light has been turned off. Chemical crosslinking which occurs in the dark is known as "postcuring". Postcuring has its origins in the trapping of radicals created during UV irradiation,and can continue reactions for hours in the dark. The phenomenon is essential in printing industry,for instance,where ink is deposited along a high speed conveyor and passes successively under groups of UV lamps arranged in banks. As "postcuring" has a contribution on the final conversion,a better understanding of the kinetics in this non-stationary state is essential for optimizing photocuring properties of formulations. Owing to the complex nature of interacting factors which evolve with the degree of curing,no existing kinetic model is capable of predicting postcuring kinetics over an extended conversion range.