Synthesis of polyols containing nitrogen-phosphorus from vegetable oil derivatives for polyurethane film applications

Methyl oleate, a kind of vegetable oil derivatives, was used as the raw material to synthesize novel polyols containing nitrogen and phosphorus (PNP) by three steps: amidaion, epoxidation, and ring-opening reaction. The structure of the ensuing PNP was characterized by gel permeation chromatography, Fourier transform infrared spectroscopy, and nuclear magnetic resonance spectroscopy. Then, polyurethane films were prepared by mixing the resulting polyols (PNP) and poly-(tetra methylene glycol) with isophorone diisocyanate in different proportions. After that, the thermostability of polyurethane films was investigated by limiting oxygen index (LOI), thermogravimetry, and cone calorimeter test. Similarly, mechanical property of polyurethane films was studied by tensile test. The results showed that as the amount of PNP increased, the tensile strength of polyurethane films increased from 2.0 to 13.5 MPa, the LOI values of polyurethane films went up from 20.1% to 25.5%. Moreover, the initial decomposition temperature of polyurethane films improved from 280 to 312°C and the total heat release drooped from 32.2 to 21.7 kW/m 2 without adding any other flame retardant. Therefore, it was observed that the polyurethane films have superior thermal stability and mechanical property and appear suitable for a wide range of applications.