固化过程中木质碳纤维原丝微细结构的生成演化

将杉木木粉经苯酚液化、熔融纺丝后，在甲醛、盐酸和蒸馏水组成的固化液中固化，得到木质碳纤维原丝。讨论了木质碳纤维原丝在固化过程中的表面形貌、官能团变化、微晶结构和热稳定性。得到的结论如下：①固化过程中，原丝表面保持平滑，未发生明显变化，固化升温时间达到4h后固化比较完全，原丝内部结构致密。②固化条件为3h＋2h时，苯环上的H原子开始被取代，原丝进入固化交联初阶段。升温时间达到4h后生成的亚甲基键和苯环上的羟基发生脱水缩合反应，生成C—O—C和少量C—C=O结构，交联反应加强。③不同固化阶段原丝的片层间距（d002）均稳定在0．448～0．479范围内，同时，沿c轴上的堆积高度（Lc）在1h＋2h时最小，2h＋2h时最大，2h后略微下降，随着固化时间增加，维持在0．805—0．833范围内。④固化初期原丝的热稳定性较差，在900℃失重率达99．3％；升温时间从2h到5h时，失重率从63．9％逐渐降到52．8％，原丝稳定性提高。⑤原丝中微孔的比例随固化时间的增加呈增大趋势，固化过程中有部分非微孔的孔隙向微孔转化。

Evolution Process of Wood-based Carbon Fiber Precursor Micro-structure during the Curing Process

Wood-based carbon fiber precursor is obtained after fir wood powder goes through liquefection in phenol and melt spinning, followed by curing in the curing liquid consisting of formaldehyde, hydrorchloric acid and distilled water. The morphology, functional group change, microcrystalline structure and thermal stability of wood-based carbon fiber precursor are discussed, with conclusions as follows： （1） During the curing process, the precursor＇s surface remains smooth, with no significant changes, with complete curing obtained after a four-hour temperature rise period in the curing process, with a dense internal structure. （2） Curing conditions ：3h ＋2h, with H atom on the benzene ring replaced, precursor entering an initial stage of crosslinking curing. After four-hour temperature rise, generated methylene linkage and hydroxyl groups on the benzene ring go through dehydration-condensation reaction and form C-O-C structure and a small amount of C-C=O structure, with crosslinking reactions enhanced. （3）The lamellar spacings （d002）of precursors maintain between 0.448 and 0.479 at different curing stages, and at the same time, the accumulation height along the axis C is the smallest in the case of 1h ＋2h and highest in the case of 2h ＋2h, slightly lower after 2h, maintaining between 0.805 and 0.833 with the increase in the curing time. （4） The thermal stability of precursors is poor at the initial curing stage, with the weightlessness rate reaching 99.3% at 900 ℃, drop from 63.9% to 52.8% during 2h -5h temperature rise period, with precursor stability increased. （5） The proportion of micropores in the precursor increases with the increase in the curing time, with some non-micropores changing to micropores in the curing process.