Modeling of Photobleaching for Photoinitiation of Thick Polymerization Systems

摘要

In this contribution, we present a mathematical modeling of the spatial and temporal variations in the light intensity, initiator concentration, and initiation rate for photobleaching initiator systems. Effects of absorption by the initiator fragments, absorption by the monomer, and diffusion of the initiator are included. The results indicate that the initiation rate profile resembles a wave-front, which propagates through the sample, and that there is an optimum initiator concentration for efficient photopolymerization of thick samples. If either the initiator concentration or molar absorptivity is increased, the initiation rate at the peak of the wave-front increases, the breadth of the propagating front decreases, and the rate of spatial propagation through the sample decreases. However, the maximum photoinitiation rate and rate of spatial propagation of the initiation front are simultaneously increased by increasing the initiator quantum yield or by decreasing the absorptivity of the monomer or photolysis products.