High performance nano-zinc amino-tris-(methylenephosphonate) in rigid polyurethane foam with improved mechanical strength, thermal stability and flame retardancy

A novel phosphorus and nitrogen-based flame retardant, zinc amino-tris-(methylenephosphonate) (Zn-AMP) was synthesized and characterized by X-ray diffraction and Fourier-transform infrared spectroscopies, transmission electronic microscopy, and thermogravimetric analysis (TGA). Zn-AMP was introduced into rigid polyurethane (RPU) foam with the aim of enhancing flame retardant, mechanical and thermal properties. The incorporation of 10 wt% Zn-AMP into RPU foam was found to increase the compressive strength by 67.9% as well as to reduce thermal conductivity compared with untreated foam. Foam containing 20 wt% Zn-AMP (sample RPU/20Zn-AMP) had a limiting oxygen index of 25.0% and a V0 rating in a vertical UL-94 test. Cone calorimeter data revealed that the peak heat release rate and total heat release of sample RPU/20Zn-AMP were decreased by 61.0 and 46.1%, respectively, compared with untreated foam. TGA results indicated that Zn-AMP clearly improved RPU foam's thermal stability. (C) 2018 Elsevier Ltd. All rights reserved.