Study On Synthesis And Flame Retardant Properties Of Boron-containing Polyurethane

Polyurethane is a kind of block polymer,which is composed of hard segment and soft segment.Polyurethane materials are widely used in construction,machinery,fine chemicals and other fields due to its adjustable soft and hard segments,good mechanical properties,wear resistance and low temperature resistance.However,due to the large amount of C,H,O and other elements in polyurethane,it is a flammable polymer material.In the process of combustion,the flame spreads quickly,releases high heat and releases toxic gases,which cause serious harm to human body.Therefore,it is necessary to develop new formulations for polyurethane materials to improve the flame retardancy of polyurethane.The environmental protection boron containing flame retardant has become a research hotspot because of its smoke suppression,good stability,good flame retardant and other advantages.Main research contents of this paper:1.Firstly,the effect of boron-containing polyols(diglyceride borate)on the flame retardancy of polyurethane was studied.Diglyceride borate was synthesized by esterification and characterized by FTIR and ~1H-NMR.The thermal stability and combustion behavior of boron-containing polyurethane were studied by TG,LOI,UL-94 and CCT.The results showed that with the increase of the content of diglyceride,the flame retardancy and thermal performance of polyurethane materials are enhanced.The LOI increased from 23.8%to 30.0%,with the content of diglyceride borate in the polymer chains increased from 13.6%to 25.7%,meanwhile char formation was enhanced and heat release reduced.It is suggested that the flame retardancy of polyurethane was positively correlated with boron content.Scanning electron microscope(SEM)images,residue digital photos,FTIR,Raman spectroscopy and X-ray diffraction(XRD)analysis of the char residues suggested the formation continuous compact char layer,and a fire retardant mechanism of condensed phase was proposed.2.Flame retardant rigid polyurethane foam(RPUF)with nitrogen-containing polyols(MADP),boron-containing polyols(diglyceride borate)and phosphorus-containing flame retardants(DOPO)were prepared by free foaming technology.The structure of MADP and diglyceride borate were characterized by FTIR and ~1H-NMR.Thermal stability and fire behaviors of RPUFs were characterized by TGA,LOI,and CCT.The results showed that MADP,DOPO and diglyceride borate had good synergistic effect and the thermal stability and flame retardancy of RPUF flame retardant composites were significantly improved.3.Flame retardant rigid polyurethane foam(RPUF)containing nitrogen polyol(MADP)and melamine borate(MB)were prepared by free foaming technology.The structure of MADP and MB were characterized by FTIR.TGA and LOI were used to test the thermal stability and flame retardancy of RPUF.The results showed that MADP had synergistic effect with MB,and the flame retardancy of polyurethane foam increased with the increase of MB content.Figure[28]table[19]reference[80]...