Photoinitiating systems for LED-cured interpenetrating polymer networks

Abstract

LED curing is becoming attractive in various applications due to specific characteristics such as long life-time, low heat generation and more energy saving. It requires the selection of suitable photoinitiating systems that exhibit long range absorption properties. For radical process, there are various commercially available photoinitiators showing a red-shift absorption. In contrast, most cationic photoinitiators have a short light absorption below 300 nm and display a limited overlap with the newly emerging visible LED light sources. Therefore, the development of photoinitiating systems with extended absorption in UVA (λ> 380nm) is of paramount importance. Free radical promoted cationic photopolymerization (FRPCP) is considered as an elegant and fairly flexible type of cationic polymerization technique. This approach is explored for the curing of interpenetrating acrylate/epoxide polymer networks.