The effect of thiol and ene structures on thiol-ene networks: Photopolymerization, physical, mechanical and optical properties

The photopolymerization of four different types of ene monomers with both primary and secondary multifunctional thiols has been evaluated. To understand the effect of ene monomer structures on polymer properties, a comprehensive investigation of the basic physical, mechanical and optical properties was conducted for the secondary and primary thiol-ene networks. The results indicate that ene structure and functionality can significantly affect the rigidity and the physical and mechanical properties of the thiol-ene networks. The heat capacity in the rubber state correlates with the network crosslink density and flexibility of the ene component. Networks formed from the secondary thiol-ene systems are basically equivalent to those made from primary thiol-enes with respect to physical, mechanical and optical properties. The secondary thiol monomer samples evaluated were found to have exceptional storage stability and relatively low odor. (C) 2009 Elsevier Ltd. All rights reserved.