Silylated Moisture Curing Polyurethane Resin

This article contained two parts. In the first part, copolyester of sebacic/terephthalic acid serial were synthesized by the condensation polymerization of sebacic acid and terephthalic acid with ethanediol and neopentyl glycol. The influence of reaction temperature, catalysts and vacuum tightness on condensation polymerization were discussed. The relationship between the structure and thermal stability of the copolyesters were studied by WAXD, DSC and TGA. Moisture curable silylated polyurethanes were obtained by the polymerization of polyurethane prepolymer and TDI. The reactive kinetics of polymerization between polyester diol and TDI were studied, as well as between chain extender and NCO terminated prepolymer. The curves of conversion a~t at different temperatures were obtained and so the reaction rate constants were measured and the activation energy was calculated by Arrhenius equation. FI-IR and DSC were used to analyze the structure and composion of the modified polyurethane resin. The influences of different soft segment and the content of silicone on the mechanical properties were also studied.1 It was shown that the crystallinity and melting point of copolyesters decreased with increasing content of terephthalic acid or neopentyl glycol respectively, but its heat-resistant properties are obviously enhanced.2 The reaction between copolyester and TDI, chain extender and NCO terminated prepolymer were of second order; with the viscosity increasing, the reaction rate decreased.3 The studies on silane endcapping reaction showed that the reaction rate and the reaction conversion of silane containing amine group was quicker and the termperature increasing was also higher.4 As the content of silane increasing, the mechanical properties of the silane modified polyurethane resin decreased and then enhanced, and thewater-resistent properties enhanced.In the other part, moisture curable silylated polyurethanes were obtained by the method of polyurethane prepolymer. The reactive kinetics of polymerization between polyether diol and TDI were studied, as well as between polyether triol and NCO terminated prepolymer. The curves of conversion a~t at different temperatures were obtained and so the reaction rate constants were measured and the activation energy was calculated by Arrhenius equation. FI-IR and DSC were used to analyze the structure and composion of the modified polyurethane resin. The influences of different soft segment and the content of silane on the mechanical properties were also studied .1 The reaction between polyether diol and TDI, polyether triol and NCO terminated prepolymer were of second order; with the viscosity increasing, the reaction rate decreased.2 As the content of polyether diol increased, the sliane modified polyurethane resin tensile stress at break decreased and tensile strain at break enhanced; and with the ratio of triol /diol increasing, the sliane modified polyurethane resin tensile stress at break enhanced and tensile strain at break decreased.3 As the content of silane increasing, the mechanical properties of the silane modified polyurethane resins decreased first and then enhanced, and the water-resistent properties were improved.