Lifetime predictions for the epoxy system BADGEn=0/m-XDA using kinetic analysis of thermogravimetry curves (original) (raw)
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J Appl Polym Sci, 2001
Master plots were used to corroborate R n-type mechanisms calculated in a previous study, using the method proposed by Criado et al. (Thermochim Acta 1989, 147, 377). Analysis of experimental data seems to belong to the family of decelerated curves (R n) in the range of conversion studied. The lifetime of the system diglycidil ether of bisphenol A (BADGE n ϭ 0)/m-xylylenediamine (m-XDA) for different decelerated mechanisms was calculated using thermogravimetric analysis. From the experimental data it was found that the optimum temperature range of use for this material is 60-100°C for all R n-type mechanisms, at which corresponding lifetimes range between 190 years and 1 year.
Journal of Applied Polymer Science, 2006
The physical aging of the epoxy network consisting of a diglycidyl ether of bisphenol A, m-xylylenediamine, and polyetherimide was studied by differential scanning calorimetry. The glass transition temperature and the variation of the specific heat capacities have been calculated using the method, based on the intersection of both enthalpy-temperature lines for glassy and liquid states. The apparent activation energy (E H) was calculated using a single method that involved separate temperature and excess enthalpy dependency. All calorimetric data were compared with those obtained for the epoxy network without thermoplastic.
Physical aging for an epoxy network diglycidyl ether of bisphenol A/m-xylylenediamine
Polymer, 2003
The physical aging of the epoxy network consisting of a diglycidyl ether of bisphenol A (BADGE n ¼ 0) and m-xylylenediamine (m-XDA) were studied by differential scanning calorimetry. The following aging temperatures have been used in this work: 60, 70, 80, 90, 100 and 110 8C. The glass transition temperature and the variation of the specific heat capacities have been calculated using the method based on the intersection of both enthalpy-temperature lines for glassy and liquid states. The endothermic aging peak, relaxation enthalpy and fictive temperature were also calculated for each aging temperature and aging time.
Thermodegradation kinetics of a hybrid inorganic–organic epoxy system
European Polymer Journal, 2005
Lifetime of the epoxy system formed by diglycidyl ether of bisphenol A, DGEBA/4,4 0 -diaminediphenylmethane, DDM, modified with the silsesquioxane, glycidylisobutyl-POSS, was calculated from thermogravimetric analysis. The activation energy of the decomposition of this system was evaluated by the integral method developed by Flynn-Wall-Ozawa (E = 88.9 ± 2.1 kJ mol À1 ) and by Coats and Redfern method (E = 85.2 ± 1.5 kJ mol À1 ). The kinetic parameters have been used to estimate the lifetime of the system POSS/DGEBA/DDM. The obtained results by two different ways are similar.
Journal of Applied Polymer Science, 1997
The curing reaction of a system consisting of a purified diglycidyl ether of bisphenol-A (BADGE, n Å 0) and 1,2 diamine cyclohexane (DCH) was studied with a differential scanning calorimeter. The objective of this article was twofold: a kinetic study from which parameters such as reaction orders, rate constants, and activation energies were determined; and a thermodynamic study where values of enthalpy (DH #), entropy (DS #), and Gibbs free energy (DG #) changes were calculated. This second study showed that an n-order path reaction mechanism was more favored than the autocatalyzed mechanism above 338 K. This fact was also checked when plotting rate constant ratio against temperature.
Study of the physical aging of the epoxy system BADGE n = 0/ m -XDA/CaCO 3
Journal of Applied Polymer Science, 2009
The physical aging of the epoxy network consisting of a diglycidyl ether of bisphenol A (BADGE n ¼ 0), m-xylylenediamine (m-XDA), and calcium carbonate was studied by differential scanning calorimetry. The glass transition temperature and the variation of the specific heat capacities were calculated using the method based on the intersection of both enthalpy-temperature lines for glassy and liquid states. The apparent activation energy was calculated using a single method that involved separate temperature and excess enthalpy dependency. All calorimetric data were compared with those obtained for the epoxy network without filled calcium carbonate.
Cure kinetics of a diglycidyl ether of bisphenol a epoxy network ( n = 0) with isophorone diamine
Journal of Applied Polymer Science, 2007
The study of the cure reaction of a diglycidyl ether of bisphenol A epoxy network with isophorone diamine is interesting for evaluating the industrial behavior of this material. The total enthalpy of reaction, the glass-transition temperature, and the partial enthalpies at different curing temperatures have been determined with differential scanning calorimetry in dynamic and isothermal modes. With these experimental data, the degree of conversion and the reaction rate have been obtained. A kinetic model introduces the mechanisms occurring during an epoxy chemical cure reaction. A modification of the kinetic model accounting for the influence of the diffusion of the reactive groups at high conversions is used. A thermodynamic study has allowed the calculation of the enthalpy, entropy, and Gibbs free energy.
Journal of Applied Polymer Science, 2009
The influence of the presence of CaCO 3 on the cure reaction of the epoxy network diglycidyl ether of bisphenol A with isophorone diamine has been studied. The total enthalpy of reaction, the glass transition temperature and the partial enthalpies at different isothermal temperatures have been determined using differential scanning calorimetry (DSC) in dynamic and isothermal mode. A kinetic model accounting the influence of the dif-fusion of the reactive groups at high conversions was used. All the kinetic parameters have been compared with those of the system without filler (CaCO 3 ).
Cure kinetics of diglycidylether of bisphenol A- ethylenediamine revisited using a mechanistic model
Journal of Applied Polymer Science, 2001
The study of the cure reaction of a diglycidyl ether of bisphenol A epoxy network with isophorone diamine is interesting for evaluating the industrial behavior of this material. The total enthalpy of reaction, the glass-transition temperature, and the partial enthalpies at different curing temperatures have been determined with differential scanning calorimetry in dynamic and isothermal modes. With these experimental data, the degree of conversion and the reaction rate have been obtained. A kinetic model introduces the mechanisms occurring during an epoxy chemical cure reaction. A modification of the kinetic model accounting for the influence of the diffusion of the reactive groups at high conversions is used. A thermodynamic study has allowed the calculation of the enthalpy, entropy, and Gibbs free energy.