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This article describes the curing behavior of diglycidyl ether of bisphenol-A using Cysteine (A)/ Methionine (B)/Cystine (C)/ mixture of 4,4′-diaminodiphenyl sulfone (DDS) and Cysteine/DDS and Methionine/DDS and Cystine in various molar ratios as curing agent. Differential scanning calorimetry was used to study the cure kinetics by recording the DSC scans at heating rates of 5, 10, 15, and 20°C/min. The peak exotherm temperature was found to be dependent on the heating rate, structure of the amino acids and on the DDS/amino acids molar ratio. A broad exotherm was observed in the temperature range of 150–245°C (EA), 155–240°C (EB), and 190–250°C (EC). Curing of DGEBA with mixture of amino acids and 4, 4′-diaminodiphenyl sulfone (DDS) resulted in a decrease in characteristic curing temperatures. Activation energy of curing reaction is determined in accordance to Ozawa's method and was found to be dependent on the structure of the amino acids and on the ratio of 4,4′-diaminodiphenyl sulfone (DDS) to amino acid. Thermal stability of the isothermally cured resins was evaluated using dynamic thermogravimetry in nitrogen atmosphere. No significant change has been observed in the char yield of all the samples, but it was highest in the system cured using either Cystine alone (EC-1) or a mixture of DDS/Cystine (EC-2, EC-3, and EC-4). © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

This article describes the synthesis, charac- terization, and thermal properties of nadimides obtained by reacting endo-5-norbornene-2,3-dicarboxylic acid anhy- dride (nadic anhydride) (NA), 4,4 0 -oxodiphthalic anhy- dride (ODA), 1,4,5,8-naphthalene tetra carboxylic dian- hydride (NTDA) in glacial acetic acid/DMF. Structural characterization of the resins was done by elemental analy- sis, IR, 1 H-NMR, and 13 C-NMR. The DSC scan showed the endothermic transition in the temperature range of 120- 2708C. Multistep decomposition was observed in the TG scan of uncured resins in nitrogen atmosphere. Isothermal curing of the resins was done at 250 and 3008C for 1 h in an air atmosphere. These cured resins were stable to (350 6 30)8C and decomposed in a single step above this tem- perature. This may be due to the retro Diels Alder (RDA) reaction. The char yield of the resins increased significantly on curing. The char yield was highest for P-2N resin and this could be due to the presence of rigid skeleton i.e. naphthalene. 2007 Wiley Periodicals, Inc. J Appl Polym Sci 107: 1628-1634, 2008