Micro-nano Paper Sensor Monitors The Whole Process Of Composite Vacuum-assisted Molding

In this study,a flexible and highly sensitive carbon nanotube buckypapers(BP)sensor has applied,the sensor is a three-dimensional mesoporous film materials formed by carbon nanatubes under intermolecular van der Waals interaction conditions,and the sensor was obtained by jet-adsorption filtration molding process from a carbon nanotube dispersion.The carbon nanopaper can be cut into any shape and embedded in the layup of the preform to be integrally formed with the composite.The information on carbon nanopaper sensor resistance during composite manufacturing process was collected by an online monitoring system in research,the resistance-correlation mechanism of the resin change-carbon nanopaper sensor in composite manufacturing was constructed,and the flow infiltration and post-cure of the resin in the vacuum assisted molding(VARI)process were monitored in real-time.It provides a new way to avoid defects in the manufacturing process of composite materials,improve process parameters and optimize production.Firstly,the carbon nanopaer sensor was infiltration by acetone and resin respectively,to demonstrate the excellent conductivity sensitivity and permeability of carbon nanopaper sensor.In the test process,the contrast method was used to compare the resin flow information collected by the BP sensor with the resin flow information obtained by real-time observation method,the results show that the information gained by two methods was basically the same.The accuracy of BP sensor in real-time monitoring of resin in the vacuum assisted molding process,the BP sensor was verified.The BP sensor was used to monitor the infiltration of resin under different of the number of fiber layers on the resin permeability was studied in combination with Darcy's law,as the number of fiber layers increases,the permeability decreases.In the subsequent research,the fiber laminate structure was changed,and the carbon nanopaper sensor was embedded in the pre-designed pre-formed 0°,45°,and 90° laminate structures to realize the whole process monitoring of the vacuum assisted molding of the composite material.It is concluded that the change of the fiber layup structure will affect the resin infiltration.The larger the overlap angle between the fibers,the longer the resin wetting time,and the curing tendency of the resin will not be due to the fiber.The number of layers and the layer structure are affected and the resin curing time is affected.