INVESTIGADORES
MAURI Adriana Noemi
artículos
Título:
The effect of epoxy excess on the kinetics of an epoxy–anhydride system
Autor/es:
ADRIANA MAURI; CARMEN RICARDDI
Revista:
JOURNAL OF APPLIED POLYMER SCIENCE
Editorial:
JOHN WILEY & SONS INC
Referencias:
Año: 2002 vol. 85 p. 2342 - 2349
ISSN:
0021-8995
Resumen:
The uncatalyzed cure of a commercial tetrafunctional epoxy monomer TGDDM (N,N,N′,N′-tetraglycidyl-4,4′-diaminodiphenylmethane) with hexahydrophthalic anhydride (HHPA), using variable stoichiometric ratios is reported. The reaction was followed by differential scanning calorimetry (DSC). Two kinds of experiments were performed: (1) fresh samples were run at several heating rates, and (2) samples, precured a certain time in an oil bath at constant temperature (i.e., 80 to 120°C), were run at 10°C/min. Two peaks were observed in the case of the epoxy excess but only one for the stoichiometric formulation: the peak at low temperature was attributed to the epoxy copolymerization with the anhydride while the peak at high temperature was attributed to the epoxy homopolymerization. The catalytic effect of the OH groups present in the epoxy monomer on the copolymerization reaction was demonstrated by the decrease in the activation energy of the propagation step when increasing the epoxy excess. There is a catalytic effect of the copolymerization product on the homopolymerization reaction. Our simplest model, proposed previously for a catalyzed epoxy/anhydride system [J. Polym. Sci. Part B: Polym. Phys. Ed., 37, 2799 (1999)], can be used to fit both isothermal and dynamical kinetic data