The Adhesion of Carbon Fibers to Thermoset and Thermoplastic Polymers

The adhesion of three carbon fibers, AS1, AS4, and XAS to thermosetting and thermoplastic polymers has been investigated using the single, embedded filament test. All three fiber types exhibited strong adhesion to the thermosets (epoxies) whereas only the XAS bonded strongly to the thermoplastics. Common explanations for low adhesion, such as weak boundary layers and surface roughness, were investigated and shown not to be responsible for the differences in adhesion. Different levels of fiber surface treatment and various organic sizings also had no effect. Surface analysis of the fibers using XPS and retention time chromatography indicate a subtle difference in the surface chemical constitution of the three fibers but the exact nature of these differences was not determined.