Preparation And Application Of Non-isocvanate Polyurethane

Non-isocyanate polyurethane as a new environmental friendly polymer materials obtained from non-isocyanate is expected to totally change the high-risk, highly toxic and high pollution status of the polyurethane industry. Multifunctional cyclic carbonates as the raw materials require the participation of CO2 in the process of synthesis. The use of CO2 not only can reduce the greenhouse effect, which is conformed to the trend of environmental protection, and can reduce costs. In addition, non-isocyanate polyurethane owes excellent hydrolysis resistance, chemical resistance and heat resistance.The actual amounts of the two main raw materials required for the reaction are determined via the measure of the purity of ethylene carbonate and 1,6-hexanedithiol, which are used to synthesize difunctional cyclic carbonate. The difunctional cyclic carbonate is synthesized by clicking reaction, and the structure and physical properties of the reaction products are characterized. Experimental results show that the synthesized product is pale yellow viscous liquid, which yield rate is 95%, and the structure characterization results are coincide with our design.The performance of isocyanate polyurethane by non-solvent method is investigated in this work. The impact of molecular weight, heat affect the stability, dynamic mechanical properties, mechanical properties and adhesion properties by the different molar ratio of difunctional cyclic carbonate (DiCC) and 4,4 diaminodiphenylmethane (MDA) are systematically studied. The research results show that:the structure characterization results are coincide with our design. When the molar ratio of DiCC and MDA is 1:1, the thermal stability of the non-isocyanate polyurethane dynamic mechanical properties, mechanical properties and adhesion properties are the best, having a number average molecular weight Mn and the weight average molecular weight Mw are 0.29×10-4 g·mol-1 and 1.15×10-4 g·mol-1 respectively. The initial decomposition temperature, the storage modulus, the glass transition temperature reach to 225 ℃,35 MPa and 22.6℃, respectively.Comparison of thermal stability and mechanical properties of different catalysts synthetic non-isocyanate polyurethane, and the influence of peroxide curing system for millable non-isocyanate polyurethane rubber mechanical properties are studied. The research results show that:the three little Lewis acid catalysts such as LiBr, ferric chloride and magnesium trifluoromethanesulfonate have little impact on the thermal stability of the NIPU product. The tensile strength reach the best of 3.1 MPa when LiBr is used as the catalyst in the synthesis of NIPU. Vulcanization curve results indicate non-isocyanate polyurethane molecular chains exist curable crosslinking points, which may be cured at a high temperature. The rubber after vulcanization, with the increase of the adding of DCP, the tensile strength of the rubber is gradually increased and the elongation at break decreased at the same time.