Thiol–norbornene materials: Approaches to develop highTg thiol–ene polymers

The ability to prepare high T-g low shrinkage thiol-ene materials is attractive for applications such as coatings and dental restoratives. However, thiol and nonacrylated vinyl materials typically consist of a flexible backbone, limiting the utility of these polymers. Hence, it is of importance to synthesize and investigate thiol and vinyl materials of varying backbone chemistry and stiffness. Here, we investigate the effect of backbone chemistry and functionality of norbornene resins on polymerization kinetics and glass transition temperature (T-g) for several thiolnorbornene materials. Results indicate that TgS as high as 94 degrees C are achievable in thiol-norbornene resins of appropriately controlled chemistry. Furthermore, both the backbone chemistry and the norbornene moiety are important factors in the development of high T-g materials. In particular, as much as a 70 degrees C increase in T-g was observed in a norbornene-thiol specimen when compared with a sample prepared using allyl ether monomer of analogous backbone chemistry. (c) 2007 Wiley Periodicals, Inc.