Naphthalene-type epoxy resin was cured with u.v. irradiation in the presence of tetrahydrofuran (THF) using sulphonium salt as a curing catalyst. In this curing process, the epoxy resin was copolymerized with the THF. Thus, evaporation of THF was sup_p_ressed substantially. The suppression of solvent evaporation decreased shrinkage of the coatings in the curing process and thus reduced internal stress at the interface between the coatings and the adherend. Fracture energy of these cured films increased with the amount of THF added, and had a maximum value when 10 wt% of THF was added. This shows that the toughness of the cured resins increases with the introduction of the flexible chains which were formed by the ring-opening reaction of THF.
Посилання на статтю:
Internal stress and mechanical properties of epoxy resin coatings cured with acid catalyst in the presence of THF / Mitsukazu Ochi*, Kazuaki Onishi and Shigehisa Ueda // Polymer. – 1992. – Vol 33. – P. 4550-4555.