The isothiocyanatophosphazene, [NP(NCS)2]3, undergoes ring-opening polymerization when heated at temperatures above 100 °C to form a low molecular weight polymer, [NP(NCS)2]n. The copolymerization of [NP(NCS)2]3 and [NP(NCS)2]3 was examined, and mechanistic implications for cyclophospha-zene polymerization are discussed. High molecular weight [NP(NCS)2]n was prepared by the metathetical exchange reaction of (NPCl2)n with potassium thiocyanate. Treatment of [NP(NCS)2]n with alcohols and amines to form thiourethane and thiourea derivatives was examined. Steric and electronic effects prevented full reaction of the isothiocyanato side groups with alcohols. However, thiourea derivatives, [NP-(NHCSNHR)2]n, were prepared by the reactions of [NP(NCS)2]n with amines. Mixed-substituent thiourethane and thiourea phosphazene polymers with trifluoroethoxy or 2-(2-methoxyethoxy)ethoxy cosubstituent groups were also synthesized. The characterization and properties of the thiourethane and thiourea phosphazene polymers are described.
All Science Journal Classification (ASJC) codes
- Organic Chemistry
- Polymers and Plastics
- Inorganic Chemistry
- Materials Chemistry