Kari Ingalls, Tidal Vision, presented the company’s chitosan products, sourced from seafood processing wastes (crab shells), which have many applications including as PIN flame retardants. Chitosan is the second most abundant biological polymer, is positively electrostatically charged, contains nitrogen and carbon, and has reactive amine and hydroxyl groups enabling binding of phosphorus or other PIN FR elements. Tidal Vision extracts and purifies chitosan from seafood wastes, to specific specifications (e.g. molecular weight range) appropriate for different industrial applications. The remaining 80% of organic-rich biomass is recycled as fertiliser. Many research studies show the potential of chitosan and derivates as PIN FRs. Aqueous application to textiles provides effective flame retardancy but is not wash durable, and cross-linking solutions are being developed to address durability.
Bob Howell, Central Michigan University, outlined a range of materials from which PIN flame retardants can be biosourced: tartaric acid, chitosan, castor oil, plant-based phenolics, glycerol / adipic acid, starch derivatives … These can be modified to produce both additive or reactive PIN FRs, and can be reacted with phosphorus to produce high performance PIN FRs which are stable in polymers but are biodegradable.