Property Study And Preparation Of Solvent-free Epoxy-imide Adhesives With High Temperature Resistance

Epoxy resin (EP) has excellent adhesion, thermal and mechanical properties, compositesbased on epoxy resin are widely used in aerospace, electronics and other fields; but the pure epoxyresin is unable to meet the requirements in these areas, because of its brittleness andlow-performance on thermal and electrical properties, the modification of epoxy resins wasrequired to increase their toughness, thermal stability and electrical properties.Polyimide has high-performance on thermal property, moist heat property electricalinsulation property,natural aging and high modulus, and low-performance on smoke productionas an ideal heat-resistant polymer. At this stage, the modification of epoxy resin with polyimideimproving the thermal stability and toughness of epoxy resin and solvent-free meet the growingrequirements of environmental protection.In this research, using thermosetting polyimide (PI-6) and thermoplastic polyimidesynthesized from CA-248or BAPP, modified epoxy resin (TGDDM and JP-80). Prepared4adhesives: TDBM, JDEM, JBEM and JDBEM, respectively, measured viscosity-temperaturedependence, gelation time-temperature dependence and tensile shear strength at7differenttemperatures. The cured adhesives (cured by100℃/1.5h+160℃/1h+180℃/1h) were takenFourier-transform infrared spectrometer (FT-IR), electrical, contact angle and surface energy andwater absorption test, evaluated the performance of the four kinds of adhesives.Prepared14adhesives (from JDBEM-1to JDBEM-14) by changing the dosage of A-30andPI-6when using thermosetting polyimide PI-6and thermoplastic polyimide synthesed withCA-248modificated JP-80expoxy resin. According to tensile shearing strength properties under7temperatures, determinee the optimal dosage of PI-6and A-30, named as adhesive JDBEM. Thechar of adhesive JDBEM is4.9%on800℃by Thermo-gravimetric analysis (TGA), showing good heat resistance. Doing the dynamic DSC scans of adhesive JDBEM, curing temperature isdetermined, calculated the reaction order, the frequency factor, peak temperatures of the reactionconstant, glass transition temperature, the best curing temperature.Four types of adhesives were with activity after placed at room temperature for96hours. Thestretch shear strength of adhesive TDBM and JDEM at high temperature were consistent withstretch shear strength at room temperature, being17-19MPa. The stretch shear strength ofadhesive JBEM in25℃, and100℃, and150℃, and180℃and200℃were highest,reached27-30MPa, but its performance in high temperature was much lower. Whereas adhesiveJDBEM-7showed a high-performance in tensile shearing strength at temperature points (25℃,and100℃, and150℃, and180℃, and200℃, and220and240c) of20MPa, maximumreached29.53MPa at240℃. The calculating surface energy of four types of adhesives is lowerthan the surface energy of the wate by testing the contact angler, showing good hydrophobicity.Adhesive TDBM has the optimal water absorption rate, only0.51%. However, adhesive JDEM,JBEM and JDBEM haved a high water absorption rate at1%-2%, becaosu of containing A-30.Analysised the FTIR spectra of four kinds of cured adhesive, the characteristic peak of the epoxyfunctional groups did not appear, indicating four kinds of adhesive were cured completely, otherpeaks matched the prediction of the experimental mechanism.The adhesive JDBEM was calculated as the optimum formula of the four kinds ofadhesives, achieving the desired objective.