Thiolene systems, studies

The general approach of graded radiation exposure can also be used to examine light driven processes such as photopolymerization [19]. For example, Lin-Gibson and coworkers used this library technique to examine structure-property relationships in photopolymerized dimethacrylate networks [38] and to screen the mechanical and biocompatibility performance of photopolymerized dental resins [39]. In another set of recent studies, Johnson and coworkers combined graded light exposure with temperature and composition gradients to map and model the photopolymerization kinetics of acrylates, thiolenes and a series of co-monomer systems [40 2]. 

The preceding study has demonstrated [2.2.1]bicycloheptenyl functionalized resins can be useful and interesting ene components in photoinitiated thiolene polymerizations. The addition of thiols to the unsaturation of this bicyclic system appears to be rapid and exothermic. The relative rates of this addition compared with allylic derivatives and vinyl ethers are quite favorable. The organic resins can be readily prepared from either polyols, f>olyamines, or acrylic precursors (Figure 10) and the yields are generally quite good. When acrylate esters are used as precursors, the cycloaddition reaction occurs spontaneously and no catalysis of the reaction is necessary. 

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