纳米纤维状微结构乙炔聚合物的相变研究

Study on the Phase-transformation of Nono-fibre

在真空中对由乙炔聚合制备的纳米纤维采用百种处理工艺进行升温相变处理，即及时抽出反应产生的气体以保持真空度和不抽出反应产生气体．TEM观察发现相变前后的微观形态均为纤维状，IR实验结果表明在两种不同处理工艺条件下得到的产物不同．在第一种处理工艺条件下，随温度升高纳米纤维发生链断裂和碳化，且相变产物的电阻越来越小，在700℃以上得到具有较高导电性的纳米导电纤维，XRD实验表明相变后产物虽未石墨化但结晶性增强，相变后产物具有较高导电性的原因可能是由于其具有类似于石墨联的离域大π键结构以及纳米钢粒子自由电子的贡献．而第二种处理工艺由于未将分解产生的小分子及时抽出使得制备的产物只发生部分碳化，导电性能较差．

Nano-fibre which was prepared by the polymerization of acetylene over nano-Cu par-ticle 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 conduc-tive 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 eash other. The conductivity of the product also illustrated this point.