Abstract: Flame retardant ramie fabrics were prepared by grafting glycidyl methacrylate (GMA) via ultraviolet (UV). Epoxy group present in GMA grafted ramie fabric (GMA-g-Ramie) was reacted with ethidene diamine (ED) and subsequently modified with orthophosphoric acid (OP) solution. Thermal degradation behaviour, flame retardant property, structure and morphology of pristine and modified ramie fabrics were investigated by thermogravimetric analysis (TGA), limit oxygen index(LOI), fourier transform infrared spectra (FTIR) and scanning electron microscope (SEM). GMA grafted onto ramie fabrics was confirmed by The SEM and FTIR results. The grafting yield of GMA increased with an increase in the concentration of GMA and BP and ultraviolet photografting period. The grafting yield arrived 35.61 % when the GMA concentration and BP concentration were 30 %(v/v) and 0.3 mol/L for 20 min, respectively, and the fabrics remained good feel. Phosphorus in modified ramie fabrics promoted the formation of char in combustion process of ramie fabrics, and improved the flame retardant of ramie fabrics. The LOI of ramie fabric grafted GMA 50.65 % after amination and phosphorylation reached 38.6 %.

Key words: ramie fabrics ultraviolet grafting, flame retardant, glycidyl methacrylate, amination, phosphorylation