| The aluminum alloy was used widely in various fields.Before the aluminum alloy was utilized,the way of the phosphoric acid anodizing of processing is usually treated to form a certain pore compact oxide film,which could increase the effective area of bonding,and obtain excellent adhesive performance and durability.It has been applied extensively as it become a standard way of adhesion in aircraft industry.When the aircraft parts or ship cabin leakage was destroyed,it needs the equipment update or maintain.However,there is not anodizing conditions for surface treatment of the aluminum alloy,which caused the adhesion of ordinary adhesive has a significant decline in mechanical properties that can't meet the needs in the unexpected situations.The use of aluminum alloy without treating has not been reported in the country.Therefore,based on the modified adhesive,to prepare the adhesive to bond the aluminum alloy on the surface without treatment,which not only saved a lot of time and financial resources,but deal with navigation emergency.In order to improve the bonding strength of aluminum alloy on the surface without treatment,especially the peel strength,the epoxy resin is co-modified with toughening agent and inorganic filler.Firstly,the epoxy resin E54 modified by different qualities of carboxyl terminated liquid silicone /acrylate resin was prepared by reaction with tertiary amine as catalysis.The second step,polyamide 600 # was used as curing agent,inorganic filler added to the modified epoxy resin.Finally,the formulation and curing process of modified epoxy adhesive were determined by the peel strength as the objective function,and its anti-aging properties and resistance to high and low temperature performance was test.The curing regularity,thermal stability and microstructures of modified epoxy resin and its adhesive were studied by IR(FT-IR),differential scanning calorimetry(DSC),dynamic mechanical analysis(DMA),thermogravimetry(TG)and scanning electron microscopy(SEM).The reason of modified epoxy resin and inorganic filler to improve the bonding strength and aging resistance of non-treated aluminum alloy with adhesive bonding was studied by using the XPS.The results showed that: 15 parts of the toughening agent,20 parts of fillers and 0.1 part of the coupling agent(100 parts of the curing agent as the basic)were the best formula for the modified epoxy adhesive.Through bonding strength test,determines the adhesive curing process: 30?/48 h,pressure is 0.1 MPa,the mass of 0.1 phr of the coupling agent 0.1(based on the mass of 100 phr of curing agent).Under the process,the peel strength reached 7.18 N/cm,shear strength is 18.75 MPa.The aging experiments show that the bonds of O-C=O and C=O in modified epoxy adhesives have the greatest contribution to improving the aging resistance of epoxy resin adhesives.In the experiments of high temperature and low temperature,the peel strength and shear strength of the modified epoxy resin adhesive can keep unchanged in the high temperature of 100? and in the of low temperature of-70?,however,the peel strength and shear strength of unmodified epoxy resin adhesive decreased obviously. |
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