| Summary: | 碩士 === 國立中興大學 === 化學工程學系所 === 96 === Two flame-retardant epoxy curing agents, 9,10-dihydro-9-oxa-10-
phosphaphenanthrene-10-yl- tris(4-hydroxyphenyl)methane (1) and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-yl- (4-aminophenyl)-
bis(4-hydroxyphenyl)methane (2), were prepared by a facile, inexpensive and one-pot procedure. The structures of the curing agents were confirmed by IR, high-resolution mass, single crystal diffractogram and NMR spectra. The effects of the reaction conditions on the yield and the structure of the product were discussed. According to the experimental data, a SN1 mechanism was proposed. The effect of electron-donating and electron-withdrawing groups on the reactivity was also discussed. Compound 1 and 2 served as curing agents for diglycidyl ether of bisphenol A (DGEBA) , cresol novolac epoxy (CNE) and dicyclopentadiene epoxy(HP7200). Properties such as glass transition temperature, thermal decomposition temperature, flame retardancy, and moisture absorption of the resulting epoxy thermosets were evaluated. The glass transition temperature, thermal decomposition temperature, flame retardancy, and moisture absorption of the resulting epoxy thermosets were evaluated. The glass transition temperatures of epoxy thermosets are in the range of 171-220 oC. The flame retardancy increases with increasing phosphorus content and a UL-94 V0 grade can be a chieved with a phosphorus content of 1.5%.
We also synthesized another novel methyl-containing epoxy curing agents (3-6) by selected o-cresol, 2,6-Dimethylphenol, o-Toluidine, and 2,6-Dimethylaniline as the third reactant. The structure of the curing agents were confirmed by IR, high-resolution mass, single crystal diffractogram and NMR spectra. Compound 3-6 served as curing agents for diglycidyl ether of bisphenol A (DGEBA) and dicyclopentadiene epoxy(HP7200). Properties such as glass transition temperature, thermal decomposition temperature, flame retardancy, and moisture absorption of the resulting epoxy thermosets were evaluated. The methyl-containing epoxy thermosets show slightly lower Tg values, moderate thermostability , lower moisture absorption and excellent flame retardancy than (1-2) curing system.
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