Microwave Heating and Curing of Joined Carbon Fiber Composites

In pursuit of superior joint strengths in carbon fiber-reinforced plastics (CFRPs), this work employed T800 carbon fiber/epoxy prepreg combined with adhesive film as the interlayer, cured using microwave technology. Dielectric constants remain impervious to significant shifts during the microwave-induced curing of the T800 carbon fiber/epoxy prepreg and adhesive film. X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FT-IR) confirmed that the cured products of varying layup thicknesses exhibited consistency, with the T800 carbon fiber/epoxy prepreg and the adhesive film all stemming from the same bisphenol A (BPA) resin system. Electron microscopy revealed similar bonding strengths across the five evaluated samples. Comprehensive assessments of static tensile and flexural behaviors were undertaken for diverse CFRP samples post-joining. Notably, a positive correlation between adhesive layer thickness and both tensile strength and three-point bending strength was observed. Specifically, Sample 5 manifested the peak tensile strength and three-point bending strength, registering at 258.16 MPa and 668.82 MPa, respectively. Contrastingly, Sample 2 boasted the maximal three-point bending modulus of 668.82 GPa, while Sample 3 achieved the zenith tensile modulus at 85.16 GPa. Based on observed experimental outcomes, bifurcated tensile and three-point bending failure models for the samples have been proposed.