MECHANICAL RECYCLING OF SHORT CARBON FIBERS AND GROUND CARBON FIBERS REINFORCED PA66

Abstract

Fiber-reinforced polymer composites occupy a fair share of structural and lightweight applications, replacing traditional materials whenever possible. Along with many advantages they offer, such as excellent mechanical properties to weight ratio, low price, fast production, the possibility of tailoring the properties for specific applications, etc. On the other hand, at the end of their lifetime, they are usually disposed of in landfills. Carbon fiber polymer composites (CFRPs) are relatively expensive materials and should be considered for recycling and reuse. Therefore, the influence of multiple cycles of mechanical recycling through grinding and injection molding was studied. PA66, PA66 reinforced with CF, and ground CF were mechanically recycled five times. Mechanical and thermal properties were determined after the first injection, as well as after the 1st, 3rd and 5th cycle of mechanical recycling. The values of mechanical properties (modulus, strength, ...) generally deteriorate, while the thermal properties remain almost unchanged. Part of the change is due to polymer degradation and part is due to fiber shortening.