Lifetime prediction of the epoxy system badgen = 0/1,2 DCH by thermogravimetric analysis

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Lifetime of the epoxy system diglycidil ether of Bisphenol A (BADGE nϭ0)/ m-xylylenediamine (m-XDA) was calculated by thermogravimetric analysis. The FlynnWall-Ozawa method is used to determine the activation energy of the reaction. Experimental lifetimes in the range of 60 -300°C vary from 1.41 10 9 (2682 years) to 3.35 10 Ϫ4min. This isoconversional method is not appropiate to calculate lifetime prediction because of high errors. Scaling factors were determined using the ratio of two reaction rates.

Lifetime predictions for the epoxy system BADGE n=0/m‐XDA using kinetic analysis of thermogravimetry curves

Fraga

Rodríguez‐Núñez

2001

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Lifetime prediction of the epoxy system DGEBA (n = 0)/1,2‐DCH modified with an epoxy reactive diluent by thermogravimetric analysis

Núñez

Villanueva

Núñez

et al. 2003

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Thermogravimetric analysis was used to predict the lifetime of two three-component systems of diglycidyl ether of bisphenol A (n ϭ 0)/1,2-diamine cyclohexane [DGEBA (n ϭ 0)/1,2-DCH] modified with different concentrations of an epoxy reactive diluent, vinylcyclohexene dioxide (VCHD). Experimental results were treated using two methods. The first method was independent of the degradation mechanism, and the second was based on the thermodegradation kinetic mechanism. The activation energies of the reaction were determined using the Flynn-WallOzawa method. These values were compared with those obtained using Kissinger's method. From experimental results it was found that the optimum temperature of service for these materials were different, so one or the other must be selected, depending on the application temperature considered.

Thermal and thermooxidative degradation of engineering thermoplastics and life estimation

Gupta

Chakraborty

Pandey

et al. 2004

This investigation deals with the thermal or thermooxidative degradation behavior of three engineering polymers [e.g., poly(ethylene terephthalate) (PET), poly-(ether sulfone) (PES), and poly(ether ether ketone) (PEEK)] by using thermogravimetry-coupled mass spectrometry (TG-MS) analysis. The experiments were conducted both in argon and in air separately to study the changes in the degradation pattern of the polymers under varied sample environments. The samples were subjected to a programmed heating rate of 10°C/min and a temperature range from ambient to 800°C. For all these polymers, the decomposition rate, percentage weight loss, and the nature of the evolved gases were found to vary while changing the environment from argon to air. Methods of nonisothermal kinetic analysis, proposed by Flynn and Wall, and the shelf life estimation, proposed by Toop, have been described.