High Value Modification Of Waste Styrene-butadiene-acrylonitrile Copolymer

Polyacrylonitrile butadiene styrene(ABS)plastics are widely used in the shell of electronic appliances because of its excellent mechanical properties and easy processing conditions.The total amount of scrap is more than 5*10~5 tons per year.The recycling of recycled ABS(R-ABS)plastics has become the focus of industry and academia.In this paper,according to the changes of molecular chain structure and interface morphology after R-ABS aging,low-cost and high-performance recycled materials were prepared with the main breakthrough point of chain expansion and repair,improvement of phase interface and increase of glue content.This kind of material has certain characteristics and innovation in structural design and preparation process.In this paper,epoxidized polystyrene butadiene styrene(ESBS)was prepared by modifying polystyrene butadiene styrene(SBS)with peroxyformic acid.The content of epoxy group was determined by hydrochloric acid pyridine method.The structure of ESBS was determined by ATR-FTIR,~1H-NMR and DSC.The results of ATR-FTIR and ~1H-NMR show that there is epoxy group in ESBS,and it is feasible to prepare ESBS by modifying SBS with peroxyformic acid.DSC results show that ESBS is a three-phase polymer,including polybutadiene(PB),epoxidized polybutadiene(EPB)and polystyrene(PS).SBS/R-ABS,ESBS/R-ABS,SBG/R-ABS,D(+)-sucrose/R-ABS blends were prepared by melt blending.SBG/R-ABS,ESBS/R-ABS,D(+)-sucrose/R-ABS successfully realized the chain expansion repair and phase interface repair of R-ABS molecular chain.The SBS/R-ABS,ESBS/R-ABS,SBG/R-ABS and D(+)-Sucrose/R-ABS were characterized by Fourier Transform Infrared Spectrometer transform infrared spectroscopy(FTIR),gel permeation chromatography(GPC),mechanical properties test,dynamic mechanical property test(DMA),scanning electron microscope(SEM)and differential scanning calorimetry(DSC).The results showed that the average molecular weight(weight)of the D increased significantly compared with that of R-ABS.The notched impact strength of the blends of ESBS/R-ABS,SBG/R-ABS and D(+)-sucrose/R-ABS increased obviously,the glass transition temperature difference(?Tg)between PB phase and San phase decreased,the particle size of dispersed phase decreased,and the compatibility of the two phases improved.This is because the epoxy group of ESBS and styrene butadiene styrene copolymer grafted with glycidyl methacrylate(SBG)reacts with the carboxyl group in R-ABS,and the hydroxyl group of D(+)-sucrose reacts with the aldehyde group and ketone group in R-ABS.It leads to the chain extension repair and phase interface repair of R-ABS.When the content of ESBS is15wt%,the notched impact strength is 13.91kJ/m~2,which is 143%higher than that of R-ABS.When the content of SBG is 15wt%,the notched impact strength is 11.19kJ/m~2,which is83.3%higher than that of R-ABS.When D(+)sucrose is 2.5%,the notched impact strength of D(+)-sucrose/R-ABS is 12.18kJ/m~2.It shows that the high value recycling of R-ABS has been realized.