Effect of a Chitosan-based Flame Retardant with a Caged Structure on Unsaturated Polyester Resin

A chitosan-based flame retardant with a caged structure of chitosan maleic acid mono (1-thio-phosa-4-hydroxymethyl-2,6,7-trioxa-bicyclic [2.2.2] octan-4-methylene) ester salt (CS-MA-SPEPA) is successfully synthesized well-characterized. The Cone Calorimeter (CC) results reveal the introduction of CS-MA-SPEPA into UPR matrix effectively reduce the HRR, TRR and SPR. More importantly, the incorporation of CS-MA-SPEPA suppresses the release of toxic gases (CO) from UPR matrix. The char residues results suggest the combination of CS-MA-SPEPA into UPR increase the degree of graphitization of the matrix and made char residues intumescent and tight, which could efficiently block the exchange of oxygen and heat.