Advancements in the Production of Continuous Carbon Fiber-Reinforced Thermoplastic Prepregs

1. Novelty in Impregnation Techniques

Conventional methods, when handling high-viscosity thermoplastic resins, often fall short in terms of resin flow and fiber wetting. To address this, researchers have introduced the suspended hot melt technique and ultrasonic-assisted impregnation. The suspended hot melt method disperses resin powder in an aqueous suspension, leveraging ultrasonic cavitation to expand fiber tows and embed resin granules uniformly between fibers. Subsequent high-temperature melting and consolidation enable the large-scale production of high-performance resins like PEEK and PPS. This eco-friendly process allows for continuous production, enhancing prepreg uniformity and mechanical attributes. Ultrasonic-assisted impregnation uses high-frequency oscillations to diminish resin surface tension, improving resin infiltration and reducing porosity while increasing interfacial bond strength.

2. Enhanced Fiber Spreading Methods

Traditional spreading methods can damage fibers, compromising mechanical performance. Researchers have developed a combined mechanical and airflow spreading technique. Mechanical spreading achieves spreading through transverse displacement via compression and friction, while airflow spreading uses compressed air to spray and bend fiber tows, widening them without direct contact. This dual approach boosts fiber spreading uniformity and reduces fiber damage, laying the ground for high-performance prepreg production.

3. Innovative Resin Systems

The choice and modification of resin systems are critical for prepreg performance. For high-viscosity resins such as PEEK and PPS, researchers have developed low-melting copolymers and nanofiller modification technologies. Low-melting copolymers reduce resin melt viscosity and enhance fluidity by incorporating flexible segments, while nanofillers improve mechanical and thermal resistance by strengthening resin-fiber interfacial bonding. Additionally, high-temperature-resistant thermoplastic sizing agents have been developed. These agents enhance resin-carbon fiber compatibility through molecular design, significantly boosting interfacial shear strength.

4. Smart Manufacturing Equipment

To realize continuous and automated production, intelligent preparation equipment has been developed. These integrated systems combine fiber spreading, resin impregnation, and prepreg winding modules. By precisely regulating temperature, pressure, and speed, they automate and intelligentize the prepreg preparation process. For instance, intelligent melt impregnation machines use screw extruders to melt the resin, achieve impregnation through dynamic mold-fiber contact, and produce prepregs via cooling, pulling, and winding. This equipment enhances production efficiency and ensures consistent prepreg quality.