Preparation and thermal properties of a novel core-shell structure flame-retardant copolymer

In order to improve the flame retardancy of polystyrene (PS), a phosphorus and nitrogen comonomer, named AC(2)NP(2), was synthesized and then incorporated into various amounts of PS by seeded emulsion polymerization. The modified methacrylate (AC(2)NP(2)) was used as the core phase, the styrene as the shell phase, then flame-retardant effect copolymers with core-shell structure were prepared successfully. The particle size was ranged from 40 to 60nm, and the structure and properties of the copolymers were characterized in detail. Notably, despite a few amounts of the AC(2)NP(2) units in the copolymers, all the copolymers exhibited significantly enhanced thermal stability and reduced flammability as compared with pure PS. Furthermore, from differential scanning calorimetry test, it was observed that the glass transition temperature was tinily influenced with the incorporation of commoner. The incorporation of P-N comonomer into PS backbone did not lead to negative effect on the glass transition behavior of PS.