Abstract: Polyether polyurethane prepolymer was capped with either methyl ethyl ketoxime and phenol, subsequently was chain extended with nonisocyanate polyurethane prepolymer, which was used to prepare the membrane. The capping and decapping temperatures of methyl ethyl ketoxime and phenol, as well as their capping effect were compared. Differential scanning calorimetry determined the capping reaction temperatures of methyl ethyl ketoxime and phenol were 100 ℃ and 80 ℃ respectively. Considering the capping effect, mechanical properties of the membrane, and environmental protection, methyl ethyl ketoxime was preferred to phenol. For the membrane based on methyl ethyl ketoxime, the tensile strength was 25.1 MPa, the elongation at break was 424 %. Thermogravimetric analysis indicated that the thermal properties of the membranes were not influenced by the capping agent.

Key words: polyurethane, sealant, non-isocyanate polyurethane