Properties and curing kinetic of diglycidyl ether of bisphenol A cured with a phosphorus-containing diamine

Abstract

Diglycidyl ether of bisphenol A (DGEBA) was cured with a new phosphorus-containing diamine, 1,4-bis(3-aminobenzoyloxy)-2-(6-oxido-6H-dibenz〈c,e〉〈1,2〉oxaphosphorin-6-yl)phenylene II, which was derived from 2-(6-oxido-6H-dibenz〈c,e〉〈1,2〉oxaphosphorin-6-yl)-1,4-dihydroxy phenylene and 3-nitrobenzoyl chloride followed by hydrogenation. The structure of the synthesized phosphorus-containing curing agent II was confirmed through EA, IR, 1H-NMR, and 31P-NMR. The curing kinetics of the DGEBA/II system were studied by the dynamic and isothermal DSC method. Dynamic kinetic parameters were calculated by using the Kissinger and Ozawa's methods, respectively. Isothermal kinetic parameters, including k1, k2, m, and n, were determined by an autocatalytic mechanism proposed by Kamal. The model gives a good description of curing kinetics up to the onset of vitrification. The glass transition temperatures of cured epoxy (DGEBA/II) were 180°C based on DMA and 170°C by DSC, respectively. The onset decomposition temperatures (Td onset) were 376 and 367°C under nitrogen and air, respectively. Char yields at 700°C were 38 and 18% under nitrogen and air, respectively. Limiting oxygen index (LOI) was 30, thus the phosphorus-containing diamine curing agent II was found to impart flame retardancy to the cured epoxy resin. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1635–1645, 1999