Oxidation of Reclaimed Carbon Fiber Surfaces for The Improvement of Fiber/Composite Adhesion
Norazlina Mohamad Yatim, Zurina Shamsudin, Azizah Shaaban, Nurhernida Abdullah Sani, Ridhwan Jumaidin, Emy Aqila Shariff
The recovery of carbon fiber (CF) from carbon fiber reinforced composites (CFRP) waste provide valuable reinforcement material for secondary structural application. Although surface modification of reclaimed-CF can improve its interfacial compatibility with composites, it may affect its strength and capability as a reinforcing material. This paper investigates the influence of different reflux time (10 – 50 min) on the oxidation of reclaimed-CF surfaces using nitric acid. The reclaimed-CF was recovered using a combination of nitrogen and oxygen atmospheres during pyrolysis at low final heating temperature (540°C). The surface chemical composition and morphology of the reclaimed-CF were investigated via FT-IR and SEM respectively. Microscopy analysis shows low nitric acid oxidation time (20 min) effectively removed residues of resin prior pyrolysis and produced a clean reclaimed-CF surface. Further oxidation activated the reclaimed-CF by the creation of more acidic functional groups on their surfaces. The acidic capacities increase with oxidation time without damaged the tubular reclaimed-CF structure. Overall, the optimized nitric acid treatment produced cleaner reclaimed-CF surfaces and more active sites for better interfacial compatibility between reclaimed-CF and composite matrix.