Study On Heat-Resistant Phthalazinone-Containing Expoxy Resin Adhesive And Their Nano-modification

Epoxy resin adhesive is widely used in industrial fields because of its good adhesive bonding strength, low shrinkage and better stability, excellent electrical insulation and high mechanical strength. However, its poor heat resistance largely limits its use in many harsh environments. Therefore, how to improve heat resistance of epoxy adhesive has attracted many researchers.In this paper, two high-performance adhesive systems were studied by introducing a new type of epoxy resin and a new curing agent, respectively. Moreover, the modification of the adhesive by nanometer SiO2 paritcles was also investigated. The main works included three parts as follows:1. Epoxy resin containing phthalazione moiety with 0.36 of epoxide number was successfully synthesized by two- step method through the reaction of 4-(4-hydroxylphenyl)-2,3-phthala-l-one and epichlorohydrin under the catalyst of triphenylphosphine and then in the presence of NaOH. The novle adhesive was then prepared including phthalazinone-containing epoxy resin obtained (shorted as DHPZ-ER) blended with biophenolic F epoxy resin as matrix and low molecular polyamide (H-4) as curing agent. The curing reaction dynamics of this adhesive was then studied in details. Its curing reaction rate is 1.154, and curing process was determined as 150℃/1h+170℃/2h+190℃/1h. The formulas of the adhesive at room temperature and 150℃after ageing 24h were optimized through orthogonal test. Optimal proportions of bisphenolic F-ER:DHPZ-ER:H-4 are 6:2:3 and 4:2:3, respectively. Their both shear strength are larger than 20MPa. Process conditions such as the adhesive glue numbers, useing coupling agent and spraying times and acid scarification time were studied.2. The dynamics of bisphenolic F epoxy cured by DHPZ-DA system were studied through DSC. Its curing reaction rate is 0.93. Curing process was determined as 150℃/1h+ 170℃/2h+190℃/1h. The system adhension performance and heat resistance was also sudied. In order to further improve its adhension performance, low molecular polyamide was used as co-curing agent. Optimal proportions of bisphenolic F-ER:DHPZ-DA:H-4 is 10:3:3, and its shear strengths at room temperature and 150℃after ageing 24h are all more than 24MPa.3. The nanometer SiO2 modification of the above-mentioned adhesive systems was studied. Firstly, the influence of the coupling agent, modified reaction temperature and reaction time was optimized through orthogonal test. The result indicates that the coupling agent is the most important impact factor. IR spectrum was used to confirm the linking reaction between nanometer SiO2 and the coupling agent. Adhesive performance and heat resistance of the above two adhesive systems modified by nanometer SiO2 are increased by more 10% and 15℃, respectively.