| Acrylonitrile-butadiene-styrene copolymer(ABS)is a common engineering plastic,which has been widely used in high performance battery packaging materials due to its high toughness and strong corrosion resistance.On the one hand,as the waste battery packaging material is contaminated with metal lead in different degrees during use,its recycling is greatly limited compared with the conventional waste ABS(wABS),so the removal of trace lead has become an important issue that must be solved.On the other hand,after 1.5 to 2 years of use of ABS plastics,the relative molecular weight and strength of wABS decrease,so it is necessary to conduct research on strengthening and toughening modification.Main research contents of this paper:(1)In this paper,the method of removing trace heavy metal lead from battery pack wABS by zone melting was studied.In order to make the work quantifiable,three kinds of standard ABS samples containing trace amounts of lead were first explored,namely,the lead nitrate solution immersion method,the lead stearate solvent method and the lead stearate coupling agent method.The results show that the standard spline prepared by lead stearate coupling agent has the most uniform and stable lead content.The standard sample of pb-containing ABS was purified by horizontal zone melting method.Orthogonal experiment was designed according to L~9(3~4).The lead content,structure,thermal stability and section morphology of ABS samples before and after zone melting were characterized by ICP-AES,FTIR,SEM and DSC.The results show that the structure,thermal stability and section morphology of pb-containing ABS plastics remain unchanged after the horizontal zone melting and purification.The lead content in the front and middle part of the spline decreased obviously while that in the end part increased obviously,indicating that the impurity lead gradually migrated to the end part.When the temperature is 260?,the speed is 1mm/s,and the number of cycles is 40,the relative effect is the best and the energy consumption is relatively low.(2)The carboxyl group and hydroxy-terminated polybutadiene(HTPB)in wABS were extended in situ by melt blending technology,and the healing of macromolecular chains was successfully realized.The real-time viscosity of the blending process was tracked by torque rheometer,and the structure and mechanical properties of the chain extension and regeneration modified wABS samples under different conditions were studied by FTIR,capillary rheometer,dynamic thermo-mechanical apparatus(DMTA),TG and SEM.The results showed that HTPB reacted with wABS,that is,the hydroxyl group in HTPB condensed with the carboxyl group in wABS.Meanwhile,compared with wABS,the molecular weight,impact strength,equilibrium torque,thermal stability and loss modulus of modified wABS are improved.When the HTPB content was 3.0 wt%of wABS,the notched impact strength reached 15.42 kJ/m~2.In addition,THE SEM image confirmed that after etching,the PB phase in the modified wABS decreased the peeling degree,and the binding force of the two phases was enhanced.(3)In order to improve the utilization efficiency of waste acrylonitrile-butadiene-styrene(wABS),the rheological property,heat resistance,dynamic mechanical properties,section morphology and mechanical properties of wABS modified by MDI were studied.The amount of modifier MDI was 0,0.3,0.6,0.9,1.2 and 1.5wt%,respectively.wABS/MDI blending modification systems with different amount of chain extender were prepared by blending modification.The rheological results showed that the introduction of MDI improved the apparent viscosity of the modified samples.DMTA results showed that the storage modulus and vitrification temperature(Tg)increased,which was consistent with the results of rheological analysis,indicating that wABS interrupt chain was repaired in the modified samples and there was only one Tg peak.TGA showed that the thermal stability of wABS was improved after MDI was added.SEM images showed that the two-phase interface of the modified samples was more fuzzy.With the increase of MDI content,the tensile property was significantly improved,increasing by 9.8%from that of#6 to#1,but the impact strength was affected.This is due to the chemical reaction between MDI and wABS after melting and mixing.Figure[24]table[11]reference[79]... |
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