Study On Environmental Stress Crack Behavior Of Plastic Part Made Of ABS

ABS is composed of acrylonitrile,butadiene and styrene copolymer abbreviation named ABS,Appearance of ABS looks like a kind of yellow or milky white granular,with complex two-phase amorphous polymer.Because of its excellent characteristics,such as high impact strength,heat resistance,low temperature resistance,electrical excellent performance,easy processing,product size stability,good surface gloss,easy surface modification,dyed easily,ABS is widely used in industrial parts and various shell manufacturing,like machinery,automobile,electronics,instrumentation and other fields,is supposed to be the widest use of engineering thermoplastics.Products in the process of manufacturing or in use,the plastic part made of ABS are often screws drilled,welding,hot pressing and surface metallizing,adhesive bonding processing.After those second treatments,which often lead to ABS plastic part stress crack and the failure ratio is very high.As we know,the crack is the fatal defect of plastic products including filamentous broken on the plastic surface,micro crack,whiten,Crack and trauma caused by part sticking mold.Due to structural design,the crack reason relates to plastic parts structure design,Mold,molding,plastic materials,Environmental stress and so on.According to the time of the occurrence of Crack of the classification,the Crack of ABS plastic products usually have two kinds1.Crack resulting from molding processPlastic products crack results from the mold in the machining process,which is easy to find the reason and improve.2.Crack during in useCrack is found after Plastic part is kept in warehouse for a while or during in use,this kind of Crack is often difficult to predict,and the consequences are fatal.The causes of environmental stress crack may have the following several aspects.2.1.Environmental stress crackThere may be brittle crack,when the plastic products are in contact with some active medium under in the presence of stress,which may cause damage to the plastic product finally.These active substances can be organic solvents such as detergent,soap,water,oil,acid,alkali,salt and other organic solvents not to swell the plastic significantly.Internal or external stress existing in the specimen or part and stress concentration like notched surface scratches,etc.is necessary conditions to the environment stress crack.E.g.ABS plastic part is occasionally notched or surface scratches during keeping in store or using,which will lead to break,even crack.2.2.Raw materialRaw materials ABS are mixed with other impurities or excessive additives.ABS plastic part would be crack in the wet conditions of heating and react with water vapor to occur catalytic crack reaction.ABS plastic part would be crack,when it stays in plug overtimeThis paper studies and analyzes the reasons for the crack of ABS plastic seal cover;it's found that O-ring is assembled with cover and adding lubricant on the cover and O-ring.Via FT-IR analysis,lubricant is made of silicon oil.Extract plasticizer from O-ring and obtain tributyl O-acetylcitratemainly detected by GC-MS.from the point of view of raw materials and environmental stresses,design special jigs for verified which one mainly leaded to cover cracked and combined with the molding process to explain the reasons for crack and bring out improvement suggestions.