Curing Mechanism and Performance Optimization of UHMWPE Fiber–Resin Matrix Composites Under Ultrasonic Effects

ABSTRACT To address the issue of poor fiber–resin interfacial bonding strength, numerous bubble defects, and insufficient mechanical properties, this study explored the curing mechanism and performance optimization of low‐melting‐point ultra‐high molecular weight polyethylene (UHMWPE) fiber–resin matrix composites under ultrasonic assistance. A single‐factor experiment was conducted to investigate the effect of ultrasonic power and exposure time on the curing of these heterogeneous composites. Fourier transform infrared spectroscopy (FTIR) analysis showed that ultrasonic treatment primarily promoted the refinement of the cross‐linked network of ether bonds without altering the chemical structure of the polymer main chain. The reinforcing effects of ultrasonic mechanical, thermal, and cavitation effects on the interfacial bonding, as well as their influence on the generation and dissolution of bubbles, were discussed. The ultrasonic mechanical effect played a positive role in improving the microstructure and interfacial bonding of the composites, while the cavitation effect removed initial bubbles. Combined cavitation and thermal effects at the optimal ultrasonic power enhanced resin flowability; however, high ultrasonic power weakened the mechanical effect and degraded the bonding between the resin and fibers. Ultrasound parameters of T = 20 s with P = 200–300 W, or P = 200 W with T = 20–30 s effectively eliminated internal bubbles. The specimens exhibited improved mechanical properties after ultrasonic treatment, achieving maximum bending strength, tensile strength, and impact strength of 193, 203.7 MPa, and 116.1 J/m 2 , respectively. These values represented increases of 27.8%, 26.8%, and 19.94% compared with the control group.