Study On The Synthesis Of Polycarbonate Polyurethane From Methyl Carbamate

Polycarbonate Polyurethane is a typical polyurethane elastomer with good biological compatibility and high resistance to oxidation and hydrolysis, which combines the rubber long-range elasticity and theplastic high strength. A green route for the synthesis of polycarbonate urethane (PCU) via transesterification and polycondensation is presented, in which the synthesis of polycarbonate urethane (PCU) is achieved by6-hexamethylene dicarbamate (HDC) and polycarbonate diols (PCDL) avoiding high-toxic1,6-hexamethylene diisocyanate (HDI). So it meets the requirement of sustainable green chemical.Different reaction conditions inculding catalyst categories and dosage, prepolymer temperature and pressure, polycondensation temperature and time, raw materials ratio are investigated acccording to their effects on the intrinsic viscosity and shore hardness. Then the optimal reaction condition are confirmed as following:dibutyltin oxide as catalyst and its dosage as0.125wt%, the raw material ratio of HDC and PCDL as n(PCDL):n(HDC)=1:0.99, prepolymerizing at100℃for1hour with20minutes’normal-pressure polymerizing and40minutes’slight vacuum polymerization(0.08MP), polymerization at185℃for4hours. So polycarbonate urethane with good performance is obtained:the intrinsic viscosity is61.30ml·g-1, Shore hardness is36.97D, the weight average molecular weight is up to51,019having narrow molecular weight distribution and the extensional-thermal decomposition temperature is301℃.