Use of diisocyanate to enhance the flame-retardant, mechanical and crystalline properties of poly (butylene succinate-co-butylene 3-hydroxyphenylphosphinyl-propionate) (PBSH)

Poly (butylene succinate-co-butylene-3-hydroxyphenylphosphinyl-propionate) (PBSH) was synthesized through polycondensation. Then, 4,4′-methylene diphenyl diisocyanate (MDI) was introduced into PBSH matrix by reactive blending. The chemical structure and properties of the blending products were investigated using Fourier Transform Infrared Spectroscopy (FT-IR), differential scanning calorimetry (DSC), limiting oxygen index (LOI) tests, thermogravimetric analysis (TGA), and vertical burning tests. The results proved that MDI can improve the mechanical properties and flame retardancy of PBSH. In addition, it was found that the crosslinking structure can reduce the hydrolysis rate of PBSH and effectively eliminate the melt-dripping of PBSH during combustion.