The natural abundance, biodegradability, and low density of plant fibers, together with biobased epoxy thermoset resin, have driven the increasing popularity of plant fiber/polymer composites (PFRPs) to wider applications in various industries. However, the striving for biomass-based flame retardants (FRs) treatment for PFRPs remained a bottleneck due to polymers’ inherent vulnerability against fire and the increasing environmental awareness. In this work, a facile two-step aqueous solution coating process was proposed for fabric surface treatment of flax fabric using fully biobased phytic acid and chitosan from polysaccharides. The treated flax fabric demonstrated self-extinguishing behavior when ignited and showed a decrease in peak heat release rate (PHRR) by 58% under combustion. The laminate produced by this treated flax fabric and biobased epoxy resin showed a decrease of PHRR by 36% and an increase of more than 200% for the time of torch fire burn-through, demonstrating intriguing flame retardance brought by only FRs treatment on flax fabric reinforcements. Various measurements were done to elaborate on the role of treated flax fabric in the flame retardancy of polymer composites.

This research is partly funded by China Scholarship Council under Grant CSC No. 202006630011.

Peer reviewed