Polyurethane elastomer synthesis: Prepolymer synthesis: prepare a prepolymer with an isocyanate content of about 11%, take a certain amount of MDI into the flask, heat to 55°C, slowly add polyol (about 100g), dripping time About 20 minutes, after the dripping, the temperature was gradually raised to 80°C for 2.5 hours, and the NCO content was tested after cooling. Synthesis of elastomer: Take a certain amount of the above-mentioned prepolymer, add BDO according to the isocyanate index of 1.05, degas under vacuum for about 8-10 minutes, and pour it on flat glass coated with release agent, with a thickness of about 1mm, 120 Cure at ℃ for 3-4h, perform performance test according to national standard, the results are as follows:

Table: Performance comparison of polypropylene carbonate type polyurethane elastomer and polyether type polyester polyurethane elastomer

Note: Polyester is butylene adipate with a molecular weight of 3000, polyether is N220, and polypropylene carbonate is a product with a molecular weight of 3000.

The test results show that the tensile and tear strength of polyurethane elastomers synthesized on the basis of polypropylene carbonate diol are much higher than those of polyether polyurethane elastomers, the tensile strength is similar to that of polyester polyols, and the elongation at break is equal to Polyether is similar and lower than polyester polyurethane elastomer. This product can be used as polyurethane raw material instead of polyether and polyester to synthesize various polyurethane products. At the same time, the experiment also found that the hardness of poly(propylene carbonate) polyurethane elastomer is much higher than that of polyester elastomer. When used to replace polyether polyol to synthesize waterborne polyurethane coatings, it can greatly increase the hardness of the product.