Studies on the Degradation and Stability of Thermal Degradation in Polysulfide-Based Polyurea

The process and kinetics of thermal degradation in a series of polysulfide-based polyurea were studied by TG,DTA and ATR-IR.Polysulfide-based polyurea was synthesized by diisocyanates,liquid polysulfide(IPDI or TDI) and 2,5-diamino-3,6-dimethylmercaptotoluene(Ethacure-300).The result indicates that two degradation mechanisms operate in polysulfidebased polyurea.Thermal degradation activation energy of polysulfide-based polyurea is few higher than polyester polyurethanes′.With the increase in content of hard segment,the thermal stability increases.The effecttion of diisocyanates on thermal stability was discussed.At 200 ℃,the mechanical properties of polysulfide-based polyurea can kept mostly.