Abstract:

 Nano-fibre which was prepared by the polymerization of acetylene over nano-Cu particle catalyst was heated to cause the phase-transfomation in vacuum by means of two different processings. The result of TEM showed that the morphology before and after the transformation was fibred. The IR spectra illustrated that the products obtained from this two different processing were different. In the first processing breaking of chains and carbonation of nano-fibre occured, with the increasing of temperature the resistance of the product gradually decreased and conductive nano-fibre was obtained above 700℃. The XRD analysis showed that the crystallinity of the product was raised. The high conductivity of the product was probably due to the conjugate π-bond structure as well as the existence of free electrons of nano-Cu particles. In the second processing the product was only partially carbonated. This was because the small molecules in the breaking of nano-fibre chains which not exhausted out and the free radicals recombined each other. The conductivity of the product also illustrated this point. 

Key words: Nano-fibre, Phase transformation, Free radical, Conductivity