| 초록 |
Recently, high performance structural adhesives based on epoxy systems have been widely used in industrial areas such as automotive and electronics. For automotive and aircraft applications, high strength and impact optimized structural adhesives based on epoxy system have been developed. For electronics applications, high modulus and high Tg adhesive materials are preferred. As key mechanical properties of high performance structural adhesives, lap-shear, T-peel and impact-peel strengths at various temperature conditions from -40 to 80℃ are measured. Flexible epoxies containing short or long thermoplastic backbones are included in the adhesives and nano-sized functional materials are dispersed in flexible epoxies. Nano-sized functional materials include core-shell rubber(CSR), surface-treated SiO2, surface-treated CaO and copolymer rubbers. In general, dicyandiamide (DICY) as a curing agent and 1-2(2-cyanoethyl)-2-ethyl-4-methylimidazole (2E4Mz-CNS) as a catalyst are used in the epoxy systems. Lap-shear and T-peel strengths are measured at 23 and 80℃ and impact-peel strengths at 23 and -40℃. CSR, inorganic particles and copolymer rubbers improve lap-shear and T-peel strengths at 23℃. CSR and synthesized flexible epoxy improve impact-peel strengths at 23℃ as well as -40℃. As a final step of adhesive design, the amount of catalyst should be determined carefully since the catalyst can significantly affect on the mechanical properties of epoxy systems. |
