Effect of chitosan/lignosulfonate microencapsulated red phosphorus on fire performance of epoxy resin

Abstract Chitosan (CH) and chitosan/lignosulfonate composite (CH/LS) were selected as shell materials for microencapsulated red phosphorus (MRP). MRP samples of RP@CH and RP@CH/LS were prepared and applied as flame retardants for epoxy resin (EP). The microstructure, chemical composition and thermal decomposition of the as prepared samples were systematically characterized. The effects of red phosphorus (RP), RP@CH and RP@CH/LS on the flame retardance performance of EP and the mechanism were investigated in detail. The results showed EP containing 7wt% RP@CH/LS got the limited oxygen index value of 30.6 %, and passed V-0 degree in the vertical burning tests. The peak heat release rate of EP/7wt% RP@CH/LS decreased 59.7 % compared with that of neat EP in the cone calorimeter tests. The shell structures also improved the interfacial compatibility between RP and the organic substrates, which was illustrated by tensile strain tests and scanning electron microscope (SEM) observation.