Acrylate monomers are popular in photopolymerization due to their fast polymerization rates and tunable structure. However, due to this rapid polymerization, acrylate-based materials are brittle and may have excessive shrinkage stress which may affect material toughness and durability. In traditional photopolymer applications, such as thin films or coatings, these shortcomings may be safely ignored or easily mitigated by modifying the monomer formulation or processing conditions. However, in thicker coatings the large amount of polymerized material may induce sufficient shrinkage stress to cause short or long-term material failure.
By adding chain transfer agents in photopolymer resins we are able to control polymer growth during photopolymerization to enhance homogeneity in photopolymers (Figure 1). I am currently focused on investigating the effects of chain transfer agents on photopolymerization kinetics of acrylate resins and characterizing final photocured materials thermomechanical properties
Figure 1. Sketch of A) an inhomogeneous network with many low-density areas and B) a homogeneous network with few areas of low crosslink density.