Search Results

You are looking at 1 - 10 of 12 items for :

  • "epoxy-amine reactions" x
  • Refine by Access: All Content x
Clear All
Journal of Thermal Analysis and Calorimetry
Authors: Lisardo Núñez, L. Fraga, M. Núñez, M. Villanueva, and B. Rial
Restricted access
Journal of Thermal Analysis and Calorimetry
Authors: Lisardo Núñez, F. Fraga López, L. Fraga Grueiro, and J. A. Rodriguez Añón

From the peak reaction temperatures as a function of heating rate, the activation energies were obtained for a system consisting of an epoxy resin (Badgen=0) and a curing agent (isophorone diamine), using a Perkin Elmer DSC7 operated in the dynamic mode. At the same time, the Arrhenius law was used to calculate rate constants.

Restricted access

Kinetic method by using calorimetry to mechanism of epoxy-amine cure reaction

Part VIII. A comparative study of some epoxy-amine reactions

Journal of Thermal Analysis and Calorimetry
Authors: R. Vinnik and V. Roznyatovsky

Abstract  

Four epoxy-amine reactions differing a number of the functional groups are compared. It has been shown that the main features of kinetics are similar for a whole family of model reactions. In series of epoxy-amine reactions analyzed, the reaction between resorcinol diglycidyl ether and m-phenylenediamine is one where increasing the viscosity of the reaction mixture leads to its vitrification during the reaction. This reaction proceeds very rapid compared with the model reactions. We demonstrate that application of kinetic techniques to analytical problems is facilitated by an understanding of the reaction mechanism involved. We report that thermokinetic method can be used for finding the activation energy in similar epoxy-amine systems through the use of times to point of the maximum in the experimental curve of the heat release rate vs. time. Our results indicate that independent of the initial reagent ratio, the conversion at the peak rate in the total curve the heat release ranges from 47 to 49%.

Restricted access

Abstract  

The procedure for the fabrication of epoxy-based polymer layered silicate nanocomposites is important in respect of the nanostructure that is developed. To further our understanding of this, the influence of an organically modified clay (montmorillonite, MMT) on the curing kinetics of an epoxy resin has been studied by differential scanning calorimetry. Clay loadings of 10 and 20 mass% are used, and isothermal as well as dynamic cures have been investigated. For both cure schedules the effect of the MMT is to advance the reaction. Kinetic analysis yields values for the activation energy, but shows that the reaction cannot be described simply by the usual autocatalytic equation. The glass transition of the cured nanocomposites is lower than that for the cured neat resin, a result that is attributed to homopolymerisation taking place in addition to the epoxy–amine reaction.

Restricted access

Abstract  

A combination of kinetic method and DSC measurements was used to examine the system of resorcinol diglycidylether-aniline. The purpose of this study is to obtain information about linear polycondensation in epoxy-amine system. The reaction of resorcinol diglycidylether (RDGE) with aniline falls into the family of epoxy-amine reaction mixtures, within of which the functional groups varies only. The molar heats and the rate constants for the three pathways were evaluated by nonlinear regression analysis of the data assuming that reaction mechanism proposed for simple molecular epoxy-amine system such as phenylglycidylether-aniline would be operative in the reaction between resorcinol diglycidylether and aniline. A feature of the present reaction system is that it proceed through the structural changes occurred with the heat effect. The loss of catalytic activity by the molecules of the reaction product was used as indicator for the structure forming in the reaction medium.

Restricted access

; however, the reaction heat remains relatively constant ( Table 1 ). The reaction heat of the two epoxy–amine reaction systems is close to the typical value (98–122 kJ/mol) gathered from a considerable number of pure epoxy–amine reaction systems [ 7 , 9

Restricted access

of a tertiary amine-epoxide zwitterion (the negatively charged oxygen) which attacks another epoxy ring to form an oligomer (polymer) via an anionic step growth mechanism [ 10 ]. As it is generally known, the epoxy-amine reaction is catalyzed by the

Open access
Journal of Thermal Analysis and Calorimetry
Authors: G. Scheltjens, J. Brancart, I. De Graeve, B. Van Mele, H. Terryn, and G. Van Assche

Results and discussion Reversible thermoset synthesis In the first step, the Jeffamine D-400 is furan functionalized through an irreversible epoxy-amine reaction with FGE. This reaction was performed at 56 °C until completion

Restricted access

that of the epoxy/amine reactions [ 8 ]. An explanation of the observed step transition for the 977-2 resin system requires knowledge of the chemical composition of the resin system. One might attribute this transition to the cross-linking reaction

Restricted access

at lower temperature may be due to epoxy-amine reaction and the high temperature exotherm may be due to etherification as well as co-curing of resins. The exothermic transition associated with curing was characterised by determining, T i = kick

Restricted access