Study On Preparation And Properties Of PC/ABS Alloy With Resorcinol Bis(Diphenyl Phosphate)as Main Flame Retardant

Polycarbonate(PC)/ acrylonitrile-butadiene-styrene copolymer(ABS)engineering plastics combines the excellent properties of PC and ABS,which is commonly used in communication equipment,car interior parts,household appliances of modern industry.On the one hand,PC/ABS maintains the good mechanical and thermal properties of PC,on the other hand it has good processing and low-cost performances of ABS.PC/ABS is flammable material and gets easier to burn with the increase of ABS,which limits its application.Therefore,the preparation of flame-retarded PC/ABS alloy that meets flame-retardant requirements of relevant industry has gradually become a research hotspot.Resorcinol bis(diphenyl phosphate)(RDP)has a high flame retardant effect on PC/ABS alloy.But on the one hand,RDP is a viscous liquid,which is not easy to process.On the other hand,RDP has a certain plasticizing effect on PC/ABS,which can reduce its heat deformation temperature.In order to improve the flame retardant performance and heat resistance of PC/ABS(mass ratio of 7:3),the flame-retarded PC/ABS with RDP as the main flame retardant were prepared.The influence of auxiliary phosphosilicon flame retardant,multi-aryl phosphate ester(PX-200)and other auxiliary flame retardants on the flame retardant property and heat resistance of PC/ABS was discussed.Firstly,vinyl trimethoxysilane(A171)and 9,10-dihydro-9-oxa-10-phosphahenanthrene-10-oxide(DOPO)underwent an addition reaction to obtain prepolymer,and then the polymer containing phosphorus and silicon elements(DOPO-VTS)was obtained by hydrolysis and condensation.The flame-retarded PC/ABS with 8.0 wt% RDP as main flame retardant and 6.0 wt% DOPO-VTS(PC/ABS/R-8/V-6)can pass UL-94 V-1@3.2 mm flame retardant grade,and the limit oxygen index(LOI)value is 25.6%,while the flame-retarded PC/ABS with 8.0 wt% RDP and 6.0 wt% PX-200(PC/ABS/R-8/P-6)can only reach the UL-94 V-2@3.2 mm level,and its LOI value is 22.9%.The results showed that the flame-retardant PC/ABS including 8.0 wt% RDP and 8.0 wt% DOPO-VTS or 8.0 wt% PX-200(PC/ABS/R-8/V-8 or PC/ABS/R-8/P-8)can reach UL-94 V-0@3.2 mm rating.But the total residual flame combustion time of PC/ABS/R-8/V-8 is shorter than that of PC/ABS/R-8/P-8.Therefore,in PC/ABS,the flame retardant effect of RDP with DOPO-VTS is better than that of RDP with PX-200.The heat distortion temperature(HDT)of PC/ABS/R-8/P-6 is 71.9 ?,and the PC/ABS/R-8/V-6 is 78.6 ?.It shows that the adverse effect of DOPO-VTS on the heat distortion temperature of PC/ABS is lower than that of PX-200.With the addition of 7.0 wt% RDP as main flame retardant and 13.0 wt% talc as auxiliary flame retardant,PC/ABS alloy can reach UL-94 V-0@3.2mm,and the limit oxygen index(LOI)was increased from 28.0 % to 31.8 %.The HDT of PC/ABS/R-7/T-13 is more than 10 °C higher than that of PC/ABS with 16.0 wt% RDP.The thermogravimetric analysis figure indicated that the thermal weight loss rate of PC/ABS/R-7/T-13 decreased,and the char residue was 24.0 %,which is 4.1 % higher than the theoretical char residue.On the infrared spectra of the thermogravimetric-infrared decomposition products of PC/ABS/R-7/T-13,there is an obvious P-O-C peak.According to the scanning electron microscope(SEM)and Raman spectroscopy of the char of PC/ABS/R-7/T-13,the outer surface and inner layer of char were compact and continuous and and the degree of graphitization of char was high.It is shown that RDP and talc composite flame retardancy is the combination of gas phase and condensation phase flame retardant.The tensile strength of PC/ABS/R-7/T-13 was 61.3 MPa,the bending strength was 110.7 MPa.Compared with PC/ABS,the tensile strength and bending strength of PC/ABS/R-7/T-13 improved.With the addition of 7.0 wt% RDP as main flame retardant,5.0 wt% DOPO-VTS and 10.0 wt% talc as auxiliary flame retardant,PC/ABS alloy can reach UL-94 V-0@3.2 mm rating.After adding 7.0 wt% of RDP and 12.0 wt% of talc or more and 5.0 wt% of DOPO-VTS,the HDT of PC/ABS can be increased by about 10 ?,which suggested that DOPO-VTS can improve the heat-resisting properties of PC/ABS.