The use of thermal analysis methods for predicting the thermal endurance of an epoxy resin used as electrical insulator
- PDF / 1,629,504 Bytes
- 11 Pages / 595.276 x 790.866 pts Page_size
- 48 Downloads / 262 Views
The use of thermal analysis methods for predicting the thermal endurance of an epoxy resin used as electrical insulator Petru Budrugeac1 · Andrei Cucos1 · Radu Dascălu1 · Carmen Paraschiv1 · Sorina Mitrea1 · Beatrice‑Gabriela Sbarcea1 Received: 4 December 2019 / Accepted: 4 August 2020 © Akadémiai Kiadó, Budapest, Hungary 2020
Abstract For the characterization of an epoxy resin composite material, the following analyses were performed: thermal analysis (TG/DTG/DTA) in nitrogen flow at five linear heating rates and under four quasi-isothermal temperature programs, coupled TG + FTIR analysis, DSC analysis in nitrogen flow, X-ray diffraction and FTIR spectroscopy. The processing of the TG data was performed by using Netzsch Thermokinetics—a software module for kinetic analysis. The dependence of the activation energy, evaluated by isoconversional methods, on the conversion degree shows that the investigated process is a complex one. The kinetic scheme and the corresponding kinetic parameters were determined by multivariate nonlinear regression program. The kinetic scheme and kinetic parameters thus obtained were used to calculate the TG curves corresponding to the quasi-isothermal temperature programs. A good agreement between the experimental and calculated TG curves has been found. The obtained results were used for the prediction of thermal lifetime of this material corresponding to some usage temperatures and to the 5% end-point criterion. Keywords Epoxy resin · Thermal degradation · Non-isothermal kinetics · Thermal endurance
Introduction The remarkable properties of epoxy resin-derived materials (mechanical and electrical properties, chemical resistance, etc.) determine their wide use in the polymer industry as adhesives, coating, molding, composites, electrical insulating materials, encapsulates for semiconductors. The utilization of these materials requires the knowledge of their thermal stability. Predicting of their useful life involves the investigation of the isothermal and non-isothermal degradation of these materials at relatively high temperatures in inert or oxidative atmospheres. The IEC-60216 standards [1], generally applied for the thermal life prediction of electro-insulating materials, are based on the assumption that the investigated material exhibits a predominant elementary process of degradation characterized by a value of activation energy that does not * Andrei Cucos andrei.cucos@icpe‑ca.ro 1
National Institute for Research and Development in Electrical Engineering ICPE-CA, Splaiul Unirii 313, 030138 Bucharest, Romania
depend on the degree of degradation. However, the application of isoconversional methods of kinetic analysis of data obtained by thermal analysis [2] has shown that the thermal and thermo-oxidative degradation processes of solid materials exhibit complex mechanisms involving several elementary steps: consecutive, parallel and/or opposed reactions, diffusion characterized by the corresponding set of kinetic triplets (activation energy, pre-exponential factor, conversi
Data Loading...
