Synthesis and properties of a new halogen-free flame retardant for polyethylene

Abstract

Purpose This paper aims to study a new halogen-free flame retardant that was prepared and characterised. Design/methodology/approach The phenyl phosphinic arid di-4-[1-(4-pheny phodphonic acid monophenyl ester-yl)-methyl-ethyl] phenyester dimelaminium (PDEPDM) was synthesised using phenylphosphonic dichloride, melamine, bisphenol A, triethylamine and dichloromethane via solvent-based reaction, that was added into the polyethylene to test flame performance. The chemical structures of PDEPDM were characterised by 1H nuclear magnetic resonance spectroscopy, mass spectrometry and Fourier transform infrared spectrometer. The thermal stability, mechanical and flame properties, and morphology for the char layer of composite materials were separately investigated using thermogravimetric analysis, tensile and charpy impact tests, limiting oxygen index (LOI) and UL-94 HB flammability standard and scanning electron microscope. Findings The results showed that the PDEPDM had been prepared successfully. When the intumescent fame retardant was added into the PE, the LOI of composite material was improved. Research limitations/implications The PDEPDM can be prepared successfully and can improve the flame resistance of composite material. Practical implications The PDEPDM has excellent flame-retardant properties and produce no toxic fumes when burnt in case of fire. Originality/value Under the optimal conditions, when the 32 per cent (Wt.%) PDEPDM was added into the PE, the LOI was 29.8, tensile strength and impact strength were 10.06 MPa and 16.77 kJ/m2.