Loading [MathJax]/extensions/MathMenu.js
Application of Printed Paper Sensors in Characterizing Curing Behavior of Thermosetting Resin Systems Using Dielectric Spectroscopy | IEEE Conference Publication | IEEE Xplore

Application of Printed Paper Sensors in Characterizing Curing Behavior of Thermosetting Resin Systems Using Dielectric Spectroscopy


Abstract:

This research article discusses the practical application of dielectric spectroscopy (dielectric analysis) in characterizing the curing behavior of a thermosetting resin ...Show More

Abstract:

This research article discusses the practical application of dielectric spectroscopy (dielectric analysis) in characterizing the curing behavior of a thermosetting resin system, i.e., melamine formaldehyde resin- impregnated paper. The insights of curing behavior help composite panel manufacturers find an optimum pressing time to achieve a trade-off between the composite panel's performance and the production cost. Real-time cure monitoring techniques, such as dielectric analysis (DEA), have been developed to overcome the limitations of trial- and-error methods, which have been in use for a long time for the same purpose. DEA measures changes in the dielectric properties of the material during the cross-linking reactions in resin and provides necessary information for the cure state of the material. In this study, paper sensors based on interdigitated electrodes were employed to measure the curing behavior of melamine formaldehyde (MF) resin-impregnated paper at isothermal conditions in the hot press. Moreover, the performance comparison of paper sensors was also done with commercial sensors. The paper sensors were found to be worked the same in performance, being better in terms of compatibility, thinness, biodegradability, low cost, flexibility, and non-heterogeneity. This study includes curing time measurement for MF resin- impregnated paper in isothermal conditions. Moreover, this study includes an analysis of the effect of temperature and pressure on the curing time of MF resin-impregnated paper. It was analyzed that curing temperature plays an important role in optimizing curing time as higher temperature leads to lower curing time, but applied pressure does not affect the curing time of the resin.
Date of Conference: 26-29 September 2023
Date Added to IEEE Xplore: 03 November 2023
ISBN Information:
Conference Location: Chemnitz, Germany

I. Introduction

In wood-based composite manufacturing, a thermosetting resin system was commonly used as a structural adhesive because, after curing, they typically show excellent dimensional stability, chemical corrosion resistance, and excellent thermal and mechanical properties [1],[2]. This curing can be done by heating energy from an oven or hot press to ensure the final product has good mechanical properties. If higher pressing time is used for curing, it may result in a higher degree of cure, but at the same time, it will increase energy costs and reduce production capacity [3]. To reach a balance between the performance of the composite panel and the cost of production, firms continuously strive to find an optimal pressing time. Generally, trial and error methods were used for optimizing the curing time, but this resulted in tedious work and didn't allow for getting information on real- time changes in the resin system. Therefore, real-time cure monitoring was needed, for which several techniques were developed, like acoustic methods, infrared spectroscopy, and dielectric spectroscopy [4]. Dielectric spectroscopy or dielectric analysis (DEA) is a widely used method to monitor the curing process of resins. When the resin undergoes cross-linking reaction, the material's dielectric property changes due to an increasing number of immobile groups that decrease the dielectric conductance [5],[6]. Various sensors such as parallel plates and interdigitated electrodes can be used for cure monitoring, providing the measurements in actual processing environments such as hot press, oven, and autoclave. In these dielectric measurements, the alternating current is measured by applying an alternating voltage between two electrodes in contact with a material. The material under test has ions and dipoles in it. Under the effect of the electrical field, ions move toward the electrode with the opposite polarity, whereas dipoles seek to orient with the electric field, and these changes provide information on the material's physical transitions and properties, including ion viscosity, reaction rate, and cure state. [5]. Many curing studies using dielectric studies were published for epoxy resin [7],[8], urea-formaldehyde resin [5], melamine formaldehyde resin [6], and phenol-formaldehyde resin [9].

References

References is not available for this document.