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

碳纤维最初是为航空航天用途而开发的，自20世纪60年代以来引起了人们的极大兴趣。虽然碳纤维的主要前体，如粘胶纤维，煤焦油沥青和聚丙烯腈通常提供高性能材料，但有必要开发更便宜和环保的来源，如生物质。通过对体积电阻率的测定，发现以木焦油为原料在800℃和2000℃下制备的生物质炭具有较高的电导率。(1)高压釜反应：在200-500 ℃下减压反应30 min，得到木焦油沥青，产率为20%~ 60%。通过程序加热以2℃/min逐渐升高温度，然后在最终温度下保持30 min。(2)木焦油沥青的高温处理：将木焦油沥青放入石英管中，然后在氮气下以2℃/min的加热速度在800℃下加热。1 h后，将沥青纤维冷却至室温，用X射线衍射仪分析产物的结构。(3)薄膜包衣：将高温处理的沥青粉碎成粉末，直至颗粒直径为10 - 30 μm左右。将粉末与PVDF在NMP（12%）中的溶液混合，然后使用具有测微计的膜涂布器涂布在PET膜上。然后将膜在烘箱中在130 ° C下干燥10分钟。(4)电导率测量：通过电阻率测量来研究生物质碳膜的电导率。用低阻仪测量了生物质炭膜的体积电阻率和表面电阻率，表明生物质炭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.