Paper-based sensors for process optimisation of resin-impregnated paper by means of dielectric analysis

Understanding the curing behavior is pivotal for manufacturers of composite panels as it aids in determining an optimal pressing time that strikes a balance between performance and production cost. Typically, commercial sensors based on polyimide are utilised for this purpose, but they are non-biodegradable and can potentially impact the mechanical characteristics of laminates once integrated. To address this issue, this study employed biodegradable, renewable, and thin paper-based sensors to investigate the curing behavior. In this project, dielectric analysis (DEA), a real-time cure monitoring technique, was utilised to measure changes in dielectric properties during resin cross-linking reactions, offering crucial insights into the material’s cure state. Additionally, the curing reactions in B-stage resin are more intricate than in liquid resin. Therefore, one of the goals of the i³Sense project is to optimise the curing process of B-stage resin-impregnated papers using paper-based sensors.

The resin-impregnated papers underwent high-temperature and pressure conditions in a hot press, transforming them into thick laminates designed for the furniture industry, as illustrated in Figure 1.

By employing paper sensors and dielectric analysis, the curing time was successfully reduced. Following this, the desired properties of laminates were evaluated for the reduced curing time. It is noteworthy that a significant reduction in curing time was achieved, potentially resulting in substantial cost and energy savings. Furthermore, the results obtained from both techniques, DEA and DSC, were compared (see Figure 2), revealing a strong correlation between them. This underscores the efficacy of paper sensors in facilitating efficient cure monitoring [1].