Renewable phosphorous-based flame retardant for lignocellulosic fibers

An easy-to-use and environmentally friendly method is proposed to increase the fire retardancy of natural fibers. Hemp fibers were phosphorylated by grafting phytic acid, a renewable phosphorous flame retardant urea in aqueous solution. The characterized X-ray fluorescence, solid state 13C 31P NMR analysis, pyrolysis combustion flow calorimetry tensile testing. swelling behavior evaluated optical microscopy observations showed that promotes consequently P N fiber. It has been also shown bleaching step delignification makes cellulose slightly more accessible for grafting. Non-flammable produced with relatively low contents (> 0.5 % w/w > 0.7 respectively). However, phosphorylation process significantly decreased crystallinity mechanical properties resulting For = 0.9 %, 30 decrease strength hemp was observed. production pyrophosphate thermal dehydration acid from results.