IN-SITU SYNTHESIS OF CARBON NANOTUBES ON FUNCTIONAL SUBSTRATES AND APPICATIONS IN NANO-COMPOSITE

摘要

Carbon in its form as nanotubes has outstanding mechanical, electrical and thermal properties. This has made carbon nanotubes (CNTs) an excellent candidate material for applications as reinforcement in advanced high performance composites. It has been shown that the remarkable properties of these nano constituents can be transferred to macro-level behavior of materials such as polymers, metals and ceramics by incorporating the nanotubes as reinforcement in their composites. The properties of the products, however, are largely influenced by the quality of the CNTs, the choice of the matrix material and the nature and properties of the CNT/matrix interface. Limitations in achieving the fullest benefits from the incorporation of CNTS in composites also arise due to the difficulties in dispersing the nanotubes uniformly into the matrix and clustering of the CNTS into bundles. Proper dispersion and alignment of the CNTs along a preferred orientation will help in achieving superior properties in the direction of orientation of the tubes. Considerable research and development efforts have focused on each of these problems and innovative solutions have been proposed. A novel method of incorporating MWCNTs into polymer matrix composites, consisting of in-situ synthesis of CNTs directly on the surface of long carbon fiber and using these fibers with a nanocoating of CNTs in composites, was developed by our group and employed for fabricating polymer matrix composites. Due to the presence of CNTs on the fiber surface significant improvements in properties were achieved in relation to plain carbon fiber reinforced composites. Individual fibers in a tow or a woven fabric showed a uniform nanocoating of CNTs. Short lengths of CNTs oriented perpendicular to the fiber surface formed initially and as growth continued these developed into a network of CNTs around individual fibers in the form of a sheath [Fig. 1].