| Polycarbonate/poly (acrylonitrile-butadiene-styrene) alloys with non-halogen flame retardants were stuied by melt molding after we got the best basic formulation of PC and ABS. We used inorganic, organic flame retardants and compound systems to modify with PC/ABS alloy, including zinc borate, magnesium hydrate (MDH), triphenyl phosphate (TPP), PX-200, organic silicone powder (LS100 and JJ-301), and sepiolite (SEP). Through the investigation of flammability, smoke density rating (SDR), thermal and mechanical properties, we obtained several types of PC/ABS blends which can be used as electrical box cover materials. Summary of conclusions are as follows.(1) The influences of ABS contents on properties of PC were investigated. The combination properties were good when the ratio of PC/ABS was 80/20. The melt index (MI) of PC/ABS alloy was 5.5g/10min, the elongation was as high as 105%, and notched impact strength was 46.8kJ·m-2, which both with the stiffness and strength of PC, and also with excellent flowability from ABS.(2) Even though both MBS and SMA had compatibition between PC and ABS, SMA performed better than MBS. Dispersed phase size of ABS in blend with SMA was less than that of MBS blend, and the dispersion was better too. Tg1 and Tg2 were close to each other. Besides, mechanical properties of PC/ABS/SMA alloy were better than PC/ABS/MBS alloy. The compatibilization results of SMA were more obvious.(3) Inorganic flame retardant MDH and ZB have no fire retardation function on PC/ABS blend when the content was less than 50 phr. However, smoke suppression of ZB on PC/ABS alloy was good. The LOI could respectively reach 29.0% and 28.8%, UL94 reached V-0 lavel, when the content of TPP and PX-200 were 20phr. And the tensile property and thermal stability of PC/ABS/PX-200 blend was better than that of blend with TPP. In comparison with JJ-301, silica powder LS100 made better performance in improving the LOI and reducing SDR.(4) Combination of TPP and PX-200 had higher efficiency in fire retardation than TPP or PX-200 alone. The LOI was 30% and UL94 reached V-0 level when the content of TPP and PX-200 was 12phr and 6phr. Moreover, the notched impact strength, tensile strength and thermal stability had been improved.(5) Combination ZB with TPP and PX-200 respectively could improve the LOI and UL94 level, reduce the SDR. The thermal stability and density of of carbon residue of PC/ABS/PX-200/ZB blend was better than those of PC/ABS/TPP/ZB blend.(6) Silica powder LS100 and SEP had synergistic flame retardant effects on PC/ABS alloy. When the ratio of PX-200/LS100 and PX-200/SEP was 15/8 and 12/6 respectively, UL94 achieved V-0 level. LOI of PC/ABS/ PX-200/LS100 alloy rose to 30.1% and PC/ABS/PX-200/SEP alloy to 29%. PX-200/LS100 decreased the SDR to 68.2% while PX-200/SEP to 71%. Because of the content of inorganic compounds PX-200/LS100 and PX-200/SEP improved the residue at 700℃ to 21% and 21.9%.(7) The comparison with Bayer FR3010 PC/ABS blend showed that, PC/ABS/4SMA/20PX-200, PC/ABS/4SMA/12TPP/6PX-200 and PC/ABS/4SMA/15PX-200/8LS100 could take place of FR3010 PC/ABS to make shell of electronic machines. The mechanical properties and thermal stabilities of the three were a little better than that of FR3010 PC/ABS. |
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