Preparation of flame retardant, smoke suppression and reinforced polyacrylonitrile composite fiber by using fully biomass intumescent flame retardant system and its sustainable recycle application

A green, environmental-friendly biomass intumescent flame retardant and smoke suppressed polyacrylonitrile (PAN) fibers was developed by blending with PA@SE reacted by phytic acid (PA) and serine (SE) and vitamin b2 (VB2). Compared with the original sample, the tensile strength and elongation at break for PAN-10%PA@SE/5%VB2 increased by 22.3% and 68.2% respectively; The peak heat release rate (PHRR) and total smoke production (TSP) had 57.4% and 65.4% reduction. Furthermore, to make full use of potential waste flame retardant PAN, the char of flame retardant PAN (PANC) was prepared, which showed excellent compatibility with cellulose and polyvinyl alcohol (PVA). Compared to blank samples, the maximum thermal decomposition rate and heat release capacity for PANC@Cellulose and PANC@PVA decreased significantly, and the fire safety for these polymers was significantly increased. This work not only prepared flame retardant PAN materials, but also provided a feasible way for the recycling of waste flame retardant PAN materials.