Study Of Non-Halogen Flame Retardant ABS Based On Benzoxazines

Non-halogen flame retardant ABS was prepared based on Benzoxazine synergizing withphosphorus flame retardants. Benzoxazine is a six-membered heterocylic compound which issynthesized by phenolic, formaldehyde and amines compounds. They not only have good heatresistance and high charring yield, but also can polymerize to generate a network structurelike phenol formaldehyde resin under heating or catalyst. Their curing temperature is close toABS resin molding temperature, so they can be applied to flame-retardance of ABS.First, non-halogen flame retardant ABS was prepared by using Benzoxazine (BOZ) andtriphenyl phosphate (TPP). The effects of components ratios and contents on the limitedoxygen index (LOI), mechanical properties and gloss of the flame retardant ABS were studied.The results showed BOZ and TPP had excellent synergistic effects on the flame retardance ofABS. When the mass ratio of BOZ and TPP was2:3and the total content was30phr，the LOIvalue of the flame retardant ABS was as high as33.7%, and the mechanical properties of theABS was good. TGA curves showed TPP can promote the formation of chars of BOZ. Theresults of gloss showed that addition of BOZ can improve the gloss of ABS.Second, the benzoxazine (BOZ)/triphenyl phosphate (TPP) flame retardant ABS wastoughened with acrylonitrile-butadiene-styrene with high rubber content (ABSHR) and nitrilebutadiene rubber (NBR). The effect of toughener on the flame retardant and mechanicalproperties was investigated. The cross-sections was characterized by scanning electronmicroscopy (SEM) and atomic force microscopy (AFM).When the content of ABSHR was10phr, the impact strength increased by35%, the effect of ABSHR on tensile strength and LOIof the toughened ABS was little. When the content of NBR was10phr, the impact strengthwas increased from4.62KJ/m2to26.3KJ/m2, however, the tensile strength and LOIdecreased. DMA results showed that Tg of benzoxazine in NBR toughened system shift4.6℃to low temperature compared with that in ABSHR toughened.Third, non-halogen flame retardant ABS was prepared by using benzoxazine (BOZ) andmicroencapsulated red phosphorus (MRP) in order to further improve its flame-retandantproperties. The effects of components ratios and contents of BOZ/MRP on properties of flameretardant ABS were studied. And the carbon layer morphology was analyzed by SEM. Theeffects of nitrile butadiene rubber (NBR) on flame retardant properties and mechanical properties of BOZ/MRP/ABS were investigated. When BOZ/MRP mass ratio was3:2and thetotal content is20%, limited oxygen index (LOI) of non-halogen flame retardant ABS is24.4%, and the vertical burning reaches UL-94V-0level. FTIR shows that-OH from heatedBOZ reacted with phosphorus oxide et al generated from burning red phosphorus, whichincreased the char residues of the flame retardant ABS. When NBR was8%, a flame retardantABS of UL-94V-0level, with tensile strength of30.8MPa, notched impact strength of11.4KJ/m2is obtained.