Modification Research Based On Aging And Degradation Mechanism Of Waste ABS And HIPS

Acrylonitrile butadiene styrene(ABS)and high impact polystyrene(HIPS)have excellent mechanical and processing properties.Therefore,they are widely used in various electronic and electrical products.However,with the discarding of a large number of electronic and electrical products,a large number of waste ABS and HIPS plastics will be produced.The random discarding of these plastics will bring huge waste of resources and environmental pollution.Therefore,the research on the modification of waste ABS and HIPS plastics and the high value recovery and utilization have important research significance.In this paper,the aging degradation of ABS and HIPS in natural use process were studied.With the comparison of new material and old material of ABS and HIPS,the aging mechanism of ABS and HIPS were put forward.Then,on the basis of the aging degradation mechanism,the hydroxyl type chain extender dianhydride(PMDA)was added to the melt chain of the waste acrylonitrile butadiene styrene plastic(rABS)and the waste high impact polystyrene plastic(rHIPS),the modified materials of rABS and r HIPS were prepared.The effects of PMDA content on mechanical properties,relative molecular weight,sectional morphology and dynamic mechanical properties of rABS and rHIPS were studied.Finally,on the basis of melting chain of PMDA,the elastomer hydrogenated styrene butadiene block copolymer(SEBS)was added to study the effects of PMDA/SEBS on the mechanical properties and melt mass flow rate of rABS and rHIPS.The results of the study are as follows:(1)ABS and HIPS have similar aging degradation mechanism.They occurred in the process of processing and use,which resulted in breakage of the polymer molecular chain,the reduction of molecular weight and the degradation of butadiene,produced oxygen group carbonyl and hydroxyl groups,resulted in the separation of the polymers and the poor compatibility,and the mechanical properties were deteriorated,especially the impact toughness.(2)The addition of PMDA has good repair effect on rABS,which connected the broken molecular chain in rABS,improved the relative molecular weight of rABS,realized the molecular repair,increased the storage modulus and loss modulus of the material,and increased the mechanical properties as a whole,and the increase of impact strength was the most obvious;At the same time,the addition of PMDA also repaired the graft copolymer PB-g-SAN,which showed that the interfacial bonding force between PB phase and SAN phase increased and the compatibility of the two phase became better.The FTIR test showed that the hydroxyl group of rABS was reacted with the anhydride group in PMDA to produce ester group;After adding SEBS and PMDA at the same time,the toughness of the rABS/PMDA/SEBS modified material was improved to a certain extent compared with rABS/PMDA,but the tensile strength of the material was decreased.(3)The addition of PMDA has good repair and modification effect on r HIPS.Compared with rHIPS,the relative molecular mass of rHIPS after chain expansion was increased,the molecular weight distribution became narrower,the energy storage modulus and loss modulus were improved,and the macroscopic performance was the overall improvement of the mechanical properties.The compatibility of PB phase with PS became better in the rHIPS after the chain expansion,and the interface was more blurred in the scanning electron microscope and the sample section was concave.The Tg and PS phase Tg in the PB phase were closer in DMA.The infrared test showed that the hydroxyl groups of rHIPS reacted with the acid anhydride group in PMDA to produce ester groups;After adding SEBS and PMDA,the impact strength of rHIPS/PMDA/SEBS modified material was improved compared with rHIPS/PMDA,which proved that SEBS and PMDA had a synergistic toughening effect on rHIPS.