Relationship between fiber structure and carbonized temperatures of carbon fiber from wood tar

碳纤维最初是为航空航天而开发的，自20世纪60年代以来引起了极大的兴趣。尽管粘胶粘胶纤维、煤焦油沥青和聚丙烯腈等碳纤维的主要原料通常提供高性能的材料，但有必要开发更便宜和环境友好的资源，如生物质。在本工作中，我们通过测量体积电阻率发现，在800℃和2000℃下以木焦油为原料制备的生物质碳具有较高的电导率。(1)高压反应：在200-500℃的减压下反应30分钟，以20%-60%的产率得到木焦油沥青。程序升温至2℃/m in逐步升温，终温保持30 m in。(2)木焦油沥青的高温处理：将木焦油沥青放入石英管中，在氮气中以2℃/m in的升温速度加热至800min。(3)薄膜涂布：将经过高温处理的沥青粉碎成粉末，直至颗粒直径在10~30μm左右，再用聚偏氟乙烯溶液加入12%的N-甲基-4-甲基-4-甲基-4-甲基-4-二甲基甲酰胺(NMP)溶液中混合，然后用涂膜器用微米级涂膜器涂覆在PET膜上。电导率测定：采用电阻率法研究了生物质炭膜的电导率。用低电阻仪测量了生物质碳膜的体积和表面电阻率，表明生物质碳膜具有较高的电导率。

Carbon fiber, initially developed for aerospace use, has attracted great interest since the 1960s. Although the main precursors of carbon fiber such as viscose rayon, coal tar pitch and polyacrylonitrile usually afford high-performance materials, it is necessary to develop cheaper and environmentally advantageous sources such as biomass. In this work, we found that the biomass carbons prepared at 800℃ and 2000℃from wood tar had high electric conductivity by measurement of the volume resistivity.(1) Autoclave reaction : The autoclave reaction was carried out for 30 min under reduced pressure at 200-500 ℃ to give wood tar pitch in 20%- 60% yields. The temperature was gradually raised by programmed heating at 2℃/min and then kept for 30 min at the final temperature.(2) High temperature treatment of wood tar pitch : The wood tar pitch was put into a quartz pipe and then heated at 800℃ with a heating speed of 2℃/min under nitrogen. After 1 h, the pitch fiber was cooled to r.t, and the structure of the product was analyzed by X-ray.(3) Film coating : the high temperature treated pitch was smashed to powder until the diameter of the particle was around 10 to 30 μm. The powder was mixed with a solution of PVDF in NMP (12%), followed by coating on PET film using film applicator with micrometer. Then the film was dried in the oven at 130℃ for 10 min.(4) Electric conductivity measurement : The electric conductivity of the biomass carbon film was investigated by means of electric resistivity measurement. The volume and surface resistivity of the obtained film was measured by using low resistivity meter, suggesting that the biomass carbon films had high electric conductivity.