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Kinetics modeling and time‐temperature‐transformation diagram of microwave and thermal cure of epoxy resins
Author(s) -
Wei Jianghua,
Hawley Martin C.,
Demeuse Mark T.
Publication year - 1995
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760350602
Subject(s) - materials science , epoxy , kinetics , diagram , microwave , thermal , composite material , isothermal transformation diagram , transformation (genetics) , thermodynamics , chemistry , physics , quantum mechanics , austenite , bainite , statistics , mathematics , microstructure , biochemistry , gene
Stoichimetric mixtures of a diglycidyl ether of bisphenol A (DGEBA)/ diaminodiphenyl sulfone (DDS) and a DGEBA/meta phenylene diamine (mPDA) were cured using both microwave and thermal energy. Fourier transform infrared (FTIR) was used for the measurement of the extent of cure and thermal mechanical analysis (TMA) was used for the determination of the glass transition temperature ( T g ). The cure kinetics of the DGEBA/mPDA and DGEBA/DDS systems were described by an autocatalytic kinetic model up to vitrification in both the microwave and thermal cure. For the DGEBA/mPDA system, the reaction rate constants of the primary amine‐epoxy reaction are equal to those of the secondary amine‐epoxy reaction, and the etherification reaction is negligible for both microwave and thermal cure. For the DGEBA/DDS system, the reaction rate constants of the primary amine‐epoxy reaction are greater than those of the secondary amine‐epoxy reaction and the etherification reaction is only negligible at low cure temperatures for both microwave and thermal cure. Microwave radiation decreases the reaction rate constant ratio of the secondary amine‐epoxy reaction to the primary amine‐epxy reaction and the ratio of the etherification reaction to the primary amine‐epoxy reaction. T g data were fitted to the DiBenedetto model. A master curve and a time‐temperature‐transformation (TTT) diagram were constructed. The vitrification time is shorter in microwave cure than in thermal cure, especially at higher isothermal cure temperatures. For the DGEBA/mPDA system, the minimum vitrification time is two to five times shorter in the microwave cure than in the thermal cure. For the DGEBA/DDS system, the minimum vitrification time is 44 times shorter in the microwave cure than in the thermal cure.