Synthesis of a CNT Nano-Coating on Carbon Fibers: It's Role on Strength, Toughness and Damage Tolerance of Polymer Matrix Composites

摘要

Carbon fibers are used as reinforcement in high performance composites. Nanotubes of carbon (CNTs) are another form of carbon with outstanding mechanical, electrical and thermal properties and therefore can be used along with carbon fibers to produce carbon fiber reinforced nanotube dispersed composites with relatively superior performance. One of the limitations in achieving the full benefits from the use of carbon nanotubes as reinforcement is the problem of dispersing the nanotubes uniformly in a matrix. In the present work a novel method of incorporating CNTs in a polymer matrix has been developed. This consists of in-situ synthesis of a nanocoating of carbon nanotubes on the surface of carbon fibers to be used as reinforcement and available in the form of tows or woven fabrics. The CNTs remain anchored to the surface of the carbon fibers and thus get dispersed in the matrix along with the fibers. Composite samples in the form of laminates have been prepared and tested for mechanical properties and for response to low energy impact loading. The measurement of mechanical properties showed a significant increase in tensile strength, toughness and shear modulus when CNTs were introduced in the matrix along with carbon fibers. Presence of carbon nanotubes on the surface of carbon fibers also showed improved damage tolerance and altered damage distribution in the samples during ultrasonic C-scan observations.