Paper‐based sensors for real‐time cure monitoring in the production of glass fiber‐reinforced phenol‐formaldehyde composites for aerospace interiors

Abstract The aerospace industries demand for advanced materials necessitates stringent quality control measures, particularly for composite structures to ensure optimal curing and structural integrity. Traditional methods like differential scanning calorimetry (DSC) and dynamic mechanical analysis, while useful, are limited to laboratory settings. This study explores the use of a printed paper‐based sensor for real‐time cure monitoring of glass fiber‐reinforced phenol‐formaldehyde (PF/GF) prepregs. The sensor, composed of a cellulose paper substrate with screen‐printed electrodes, offers flexibility, ease of integration, and cost‐effectiveness compared to commercial polymer‐based dielectric sensors. Real‐time monitoring with the printed paper‐based sensor was conducted at temperatures ranging from 130 to 180°C, both with and without pressure, and validated against DSC and Fourier‐transform infrared (FTIR) spectroscopy. The results showed a strong correlation between real‐time monitoring and the DSC prediction model, as well as FTIR spectroscopy. Notably, the real‐time monitoring revealed a shorter curing cycle on the production line than the predicted cure kinetic model, which is crucial for large‐scale production, such as fabricating honeycomb panels for aircraft interiors. This research underscores the importance of innovative sensor technologies in improving quality control and manufacturing efficiency in aerospace composites. Highlights Cure Monitoring of PF‐based prepregs was carried out using paper‐based sensor. Sensor offered reproducibility and seamless integration in composites. Sensor data showed a strong correlation with DSC and FTIR spectroscopy results. Paper sensors enable online monitoring of composite in aerospace manufacturing.