Abstract: Poly-N-isopropylacrylamide was introduced into the solution of polyurethane forming a semi-interpenetrating polymer network (semi-IPNs), and the semi-IPNs were cast into different coagulation baths. Fourier transform infrared spectroscopy and scanning electron micrograph were employed to characterize their structure. The swelling behavior and tensile properties of the semi-IPNs were also tested. It showed that the semi-IPNs films had better mechanical properties and more uniform structure than the films based neat polyurethane. The semi-IPNs films formed in water had better properties than in alcohol and isopropanol, and had higher temperature sensibility.

Key words: polyurethane, poly-N-isopropylacrylamide, semi-interpenetrating polymer network, coagulation, medium, leather, thermosensitivity