U Surface modification of carbon fiber as a protective strategy against thermal degradation

Carbon fibers were surface modified with acrylate-derived polymers with aromatic side chains, to protect the fiber when exposed to high temperatures. The surface modification process induced a significant increase in tensile strength (23.7%) and tensile modulus (8%), for the benzyl-bearing side chain and retained superior tensile strength (20%) and tensile modulus (7%) after heating to 600 degrees C. Commercial carbon fibres gave a significant decrease in tensile strength and modulus, 7% and 4%, respectively, when exposed to the same conditions. This suggests that the surface modification process provides a protective effect against thermal degradation, with possible application in carbon fibre recycling. The interfacial shear strength (IFSS) showed significant improvement before (up to 208%) and after (up to 84%) exposure to high temperatures. Analysis of the carbon fiber surface by XPS suggests that the surface bound polymer becomes more graphitic, potentially-via the fusion of the aromatic side chains.