PHOSPHORUS-CONTAINING POLYURETHANES BASED ON BISPHENOL-A VIA N-ALKYLATION

Phosporus-containing polyurethanes (PU-P) based on bisphenol A were pr epared by N-alkylation. The structures of N-alkylated polyurethanes we re characterized by IR and H-1 NMR spectra. Physical and thermal prope rties of the phosphorus-containing polyurethanes were investigated wit h differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction, tests of solubility, limiting oxygen index ( LOI) and reduced viscosity. T-g of the N-alkylated polymers decreased from 120 degrees C for the starting polymer to 29 degrees C of the 2.0 wt.-% phosphorus-containing polyurethanes. The viscosity of N-alkylat ed polyurethanes also decreased from 0.36 dL g(-1) to 0.24 dL g(-1). T he thermal stability of polyurethanes decreased on the introduction of phosphorus groups. The LOI values of polyurethanes showed that fire r esistance of phosphorus-containing polyurethanes was enhanced. X-ray d iffraction measurements showed that the increased phosphorus content w as accompanied by decreased crystallinity of the polyurethanes. The so lubility of PU-P was improved.