| Epoxy materials are widely used in many areas because of their excellent and balanced mechanical, thermal and electrical properties; however, the inadequate toughness limits their application. Epoxy is also used as protective coatings, however its resistances to acid and base as well as cure shrinkage may need to be further improved. In order to address those issues, three hyperbranched polymers were synthesized and used to modify BPA type epoxy, which lead to high performance epoxy matrix and protective coatings.Using A2+B3 and A2+B4 method, two hyperbranched molecules (HBP3 and HBP4) were synthesized using 1,4-butanediol diglycidyl ether, B3, and B4. Effects of reaction condition, including solvent type, monomer ratio, reaction temperature and time, on molecular weights and its distribution were investigated; and the final product were fully characterized.HBP4 was added into E51/NMA curing system to improve its toughness. Optimum mechanical and thermal properties were achieved at 5wt% loading. The tensile strength, impact strength and glass transition temperature (Tg) increase 26.3%,36.4%, and 9.1?, respectively. Several model-free kinetic models were used to evaluate the dynamic cure data and show that addition of HBP4 can lower activation energy. HBP4 was also successfually introduced into E51/NX-2007 coating system without compromising processability, a protective coating, which has much improved film hardness, adhension, impact strength and reisstance to acid and base, was obtained by spraying.Hyperbranched oxetane (POXEM) was prepared using 4-fluorophenyl sulfone, trimethylol propane, and 3-methyl-3-oxetanemethanol, and its structure was characterized. When added into E51/ethylamine-borontrifluoride curing system, the Tg is 12? higher, and impact strength increases 22.8%. |
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