Synthesis and characterization of polymers based on the cyanate functional group

The chemistry and growth of polymer structures based on the cyanate linkage has been studied. The monofunctional model compound 2‐(4‐cyanatophenyl)‐2‐phenylpropane was used to study the reaction products. The synthesis was performed with four different transition metal catalysts and also without a catalyst. The quenched products were analyzed using Size Exclusion Chromatography(SEC) and ¹³C NMR. It was found that the reaction is relatively clean, with trimerization being the major product. A few side products were also detected, which included dimers and higher oligomeric species. Crosslinked polymers were synthesized without catalyst based on the bifunctional monomer 2, 2‐bis(4‐cyanatophenyl)propane. The structure was analyzed using ¹³C NMR. The conversion and number‐average degree of polymerization based on ¹³C NMR is reported. Conversion at the gel point was found to be higher than 60%. On this basis it was concluded that polymerization based on cyanate linkages at the conditions studied is diffusion controlled and therefore not described by Flory's mean‐field theory.