Biomass intumescent flame retardant polyacrylonitrile composite: flame retardancy, smoke suppression and recycling

A fully biomass intumescent flame retardant (IFR) system was fabricated by combining the reaction product (PA@HS) of phytic acid (PA) and hydrolyzed silk (HS) with potato starch (PS), which was then blended with polyacrylonitrile (PAN) to obtain flame retardant PAN (FR-PAN). The tensile strength and elongation at break for PAN-10%PA@HS/5%PS sample increased by 18.8% and 86.3%. The peak heat release rate (PHRR) and peak smoke production rate (PSPR) decreased by 54.8% and 79.3% respectively, exhibiting excellent flame retardant and smoke suppression performance. Furthermore, the PAN-10%PA@HS/5%PS sample was carbonized to prepare FR-PAN Char (FRPC), which was then used for cellulose and polyvinyl alcohol (PVA) modification. The maximum thermal decomposition rate and PHRR of modified cellulose and PVA were significantly reduced, showing the improved fire safety. This work not only prepared an eco-friendly fully biomass flame retardant PAN composite, but also realized the successful recycling of waste flame retardant PAN materials.

Automated summary

A fully biomass intumescent flame retardant (IFR) system was developed by blending a reaction product (PA@HS) of phytic acid (PA) and hydrolyzed silk (HS) with potato starch (PS), and then combining it with polyacrylonitrile (PAN) to obtain flame retardant PAN (FR-PAN). The resulting FR-PAN showed improved tensile strength, elongation at break, and reduced heat release rate and smoke production rate, indicating excellent flame retardant and smoke suppression performance. Furthermore, the waste FR-PAN materials were successfully recycled through the preparation of FR-PAN Char (FRPC) for cellulose and polyvinyl alcohol (PVA) modification, leading to enhanced fire safety.