| In material science,structural composites have been studied deeply because of their excellent properties.Rubber in metal materials and polymer materials have a great difference in chemical structure and mechanical properties,the composite parts bonded by the two have both advantages,can be used in many occasions,so the metal rubber hot vulcanization composite system has a very important application in many industrial fields.The sealing polyurethane adhesive has excellent adhesion property to metal and good storage stability.Functionalized modification of styrene butadiene rubber is an effective method to improve the compatibility with polar fillers and enhance the bonding property with metal.In this paper,a hot vulcanization adhesive of styrene-butadiene rubber modified by sealing polyurethane was prepared to bond metal(steel).The main research contents are as follows:In this study,diphenylmethane-4,4’-diisocyanate(MDI)and polyadipate-1,4-butanediol ester diol(PBA)were used to synthesize polyurethane prepolymer,and butanone oxime(MEKO)was used as the blocking agent.The synthesis and sealing of polyurethane prepolymer were proved by infrared spectrum analysis.A closed polyurethane adhesive was prepared by using isopharone diamine(IPDA)and 4-4’-diamino-dicyclohexylmethane(PACM)as chain extenders.The unsealing and expanding behaviors of the polyurethane adhesive at 160 ℃ were studied by infrared spectrum analysis.TG/DTG analysis results showed that the thermal stability of the product was better when PACM was used as chain extender when the unsealing temperature was around 150℃.When the wet curing time is 7 days,the NCO content is 4.8%,and the IPDA chain extension coefficient is 0.6,the tensile shear strength of the sealant is the maximum,which is 4.07 MPa.In this study,by using in-chain grafting technology,acrylic acid(AA)as the grafting monomer and BPO as the initiator,the solution of grafted styrene-butadiene rubber was prepared in the mixed solvent of toluene ethyl acetate.The success of grafting reaction was proved by infrared spectrum analysis.Both the amount of monomer and BPO affected the viscosity of the solution,and the graft rate increased with the increase of the amount.In this study,rubber-metal hot vulcanization adhesive was prepared by using synthetic sealing polyurethane adhesive and grafted styrene-butadiene rubber solution,together with self-made viscosifier,accelerant,sulfur,zinc oxide and stearic acid.Steel sheet and styrene butadiene rubber compound were bonded by double coating bonding process.The effects of the amount of sealant polyurethane,the amount of tackifier and the grafting ratio of grafted rubber on the tensile shear strength of the hot vulcanized adhesive were investigated.When NCO content of the sealant is 4.8%,IPDA chain extension coefficient is 0.9,grafted styrene butadiene rubber grafting rate is 13.6%,and solid content ratio of each component is 4:1:3,the maximum tensile shear strength is 1.4MPa. |
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