Curing Of Diglycidyl Ether Of bisphenol-A Research Articles

Temperature Monitoring on Microwave Curing of DGEBA E-51 and 4,4’DDM System

Temperature monitoring was done on microwave curing of epoxy resin system consisting of di-glycidyl ether of bisphenol-A(DGEBA) E-51 and curing agent 4,4’diamino-diphenyl-methane (DDM). The study shows that microwave curing of epoxy resin system is an exothermic reaction and the temperature variation during microwave processing has the obvious characteristics of “temperature increment - heat release - temperature falling”. Analysis on the infrared thermal images indicates that each moulding body has its own temperature distribution and differs from others. The non-uniform temperature distribution reveals the uneven electric field distribution in the domestic microwave oven.

Curing and thermal behaviour of epoxy resin in the presence of a mixture of imide-amines

Abstract The curing behaviour of diglycidyl ether of bisphenol-A (DGEBA) was investigated by the dynamic differential scanning calorimetry using varying molar ratios of aromatic imide-amines and 4,4′-diaminodiphenylsulfone (DDS). The imide-amines were prepared by reacting 1 mole of naphthalene 1,4,5,8-tetracarboxylic dianhydride (N) and 4,4′-oxodiphthalic anhydride (O) with 2.5 moles of 4,4′-diaminodiphenyl ether (E) or 4,4′-diaminodiphenyl methane (M) or 4,4′-diaminodiphenylsulfone (S) and designated as NE/OE or NM/OM or NS/OS. The mixture of the imide-amines and DDS at ratio of 0:1, 0.25:0.75, 0.5:0.5, 0.75:0.25 and 1:0 were used to investigate the curing behaviour of DGEBA. A single exotherm was observed on curing with mixture of imide-amines and DDS. This clearly shows that the two amines act as co-curing agents. Curing temperatures were higher with imide-amines having sulfone linkage irrespective of anhydride. Curing of DGEBA with mixture of imide-amines and or DDS resulted in a decrease in characte...

Curing behavior of liquid crystalline epoxy/DGEBA blend

AbstractThe effect of liquid crystalline epoxy (LCE) resin on the curing behavior and thermomechanical properties of diglycidylether of bisphenol A (DGEBA) was investigated. LCE was blended with DGEBA and curing behavior of the blend was studied according to LCE content in the blend. Curing of DGEBA was accelerated and thermomechanical properties of DGEBA were considerably improved by the addition of LCE, which acted as a molecular reinforcement. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007

Study of the reaction mechanism of the copper chelate with DGEBA using DSC

The reaction mechanism of metal-containing and complex compound with epoxy oligomer of diglycidyl ether of bisphenol A (DGEBA) was studied using dynamic DSC technique. It is shown that cure reaction of the epoxy oligomers with copper acetate proceeds at two stages: through coordination of cation with the epoxy group, and through ionic polymerization at high temperatures. Mechanism of curing of DGEBA with copper chelate depends on equilibrium process of dissociation of the chelate which, in turn, depends not only on temperature of curing but also on concentration of the hardener. At the dissociation temperature of the hardener, polymerization proceeds according to ionic mechanism. Hardening of the epoxy oligomers due to interaction of epoxy groups with unconnected amine groups predominate at higher temperatures or at higher concentrations of the hardener. At low temperatures and small concentrations of the hardener, polymerization proceeds according to catalytic ionic mechanism.

Curing of diglycidyl ether of bisphenol A by aromatic diamines and thermal behaviour of cured resins

The curing of diglycidyl ether of bisphenol A (DGEBA) with N,N'-bis-(4-aminophenyl)-1,4-benzoquinone diimine (Q) was investigated as a function of diamine concentration. The glass transition temperature (T g ) of the cured resin was determined by DSC. The maximum value of T g (170°C) was obtained when a stoichiometric amount of Q was used. At low phr of diamine T g was very low. This may be due to incomplete curing of DGEBA. The activation energy of curing as determined by multiple heating rates was found to be 102 kJ mol -1 . The curing of DGEBA with mixed diamines, i.e. Q and 4,4'-diaminodiphenylsulfone (DDS) (stoichiometric amount), was also investigated. A decrease in the onset temperature of curing and a broadening of the exotherm were observed when mixed diamines were used. The cured resins were stable up to 330°C and decomposed in a single step. The char yield at 800°C of DGEBA cured with Q was high (29%).

Effect of structure of aromatic diamines on curing characteristics, thermal stability, and mechanical properties of epoxy resins. I

The curing behavior of diglycidyl ether of bisphenol-A (DGEBA) with aromatic diamines having aryl–ether, aryl–ether–carbonyl, and aryl–ether–sulfone linkages was studied using differential scanning calorimetry (DSC). Aromatic diaminessuch as 1,3-bis(aminophenoxy)benzene (R), 1,4-bis(aminophenoxy)benzene (H),2,2′-bis[4-(4-aminophenoxy)phenyl]propane (B), 4,4′-bis(4-aminophenoxy)benzo-phenone (P), and bis[4-(4-aminophenoxy)phenyl]sulfone (S) were synthesized and characterized in the laboratory. Curing of DGEBA was done using both stoichiometric and nonstoichiometric amounts of diamines and the reaction was monitored using DSC. The reactivity of the diamines depended on the structure. The presence of electron withdrawing groups, even though significantly apart from the reaction site, reduced the nucleophilicity. No significant change was observed in the activation energy for curing, which was around 56 ± 2 kJ/mol. The glass transition temperature of the epoxy network depended on the structure and was higher when diamines P and S were used in comparison to diamines R, H, and B. The cured resins were stable up to 300°C, and maximum char yield (i.e., 32% at 600°C) was obtained in DGEBA cured with diamine P. The room temperature mechanical properties only changed marginally with the structure of the diamines. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1759–1766, 1998