Influence of the reactivity of amine hydrogens and the evaporation of monomers on the cure kinetics of epoxy-amine: kinetic questions

✍ Scribed by Senen Paz-Abuin; Mercedes Pazos Pellin; Marta Paz-Pazos; Arturo Lopez-Quintela

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 783 KB
• Volume: 38
• Category: Article
• ISSN: 0032-3861
• DOI: 10.1016/s0032-3861(96)00957-3

✦ Synopsis

The mechanism of cure (pre~el) of a highly purified diglycidylether of bisphenol A (DGEBA, 99.6% molecular weight = 340 g mol -') with 1,3-bis(aminomethyl)-cyclohexane (1,3 BAC) was studied. A kinetic model was developed which considered the different reactivities of the amine hydrogens involved in the process. The possibility of simultaneous evaporation of the starting monomers and its influence on the rate of reaction is also taken into account. The rate constants of the elementary process and the general mechanism were determined. The ratio of the elemental rate constants, R (secondary amine to primary amine), is obtained directly from a simple equation, its value being < 1/2, decreasing with temperature. Our results show that the noncatalytic path is more important than the catalytic one up to 20% of the reaction. Differential scanning calorimetry (d.s.c.) and gas chromatography-mass spectrometry (g.c.-m.s.) were used for epoxy and amine quantification respectively. G.c-m.s. proved a very powerful technique for quantification of the amine.