Influences of Absorbed Dose Rate on the Mechanical Properties and Fiber–Matrix Interaction of High-Density Polyethylene-Based Carbon Fiber Reinforced Thermoplastic Irradiated by Electron-Beam

In this study, a high-density polyethylene (HDPE)-based carbon fiber-reinforced thermoplastic (CFRTP) was irradiated by an electron-beam. To assess the absorbed dose rate influence on its mechanical properties, the beam energy and absorbed dose were fixed, while the absorbed dose rates were varied. The tensile strength (TS) and Young’s modulus (YM) were evaluated. The irradiated CFRTP TS increased at absorbed dose rates of up to 6.8 kGy/s and decreased at higher rates. YM showed no meaningful differences. For CFRTPs constituents, the carbon fiber (CF) TS gradually increased, while the HDPE TS decreased slightly as the absorbed dose rates increased. The OH intermolecular bond was strongly developed in irradiated CFRTP at low absorbed dose rates and gradually declined when increasing those rates. X-ray photoelectron spectroscopy analysis revealed that the oxygen content of irradiated CFRTPs decreased with increasing absorbed dose rate due to the shorter irradiation time at higher dose rates. In conclusion, from the TS viewpoint, opposite effects occurred when increasing the absorbed dose rate: a favorable increase in CF TS and adverse decline of attractive hydrogen bonding interactions between HDPE and CF for CFRTPs TS. Therefore, the irradiated CFRTP TS was maximized at an optimum absorbed dose rate of 6.8 kGy/s.