Effects of curing process on microstructure characterization and thermal stability of liquefied wood carbon fiber precursors

A new carbon fiber precursors was prepared by liquefied wood in phenol. The liquefied wood was modified to spinning solution by adding hexamethylenetetramine, melt-spinning then cured in combined solution of hydrochloric acid and formaldehyde to obtain precursors. The pore structure, microcrystalline structure and thermal stability of liquefied wood carbon fiber precursors were studied. The results show that the adsorption isotherm of N₂ for as-spun fibers and precursors belongs to type Ⅱ , the specific surface area of as-spun fibers is 0.517 m²·g^-1, and precursors is 0.142 m²·g^-1. Wood powder form Chinese fir has typical diffraction peaks of cellulose Ⅰ . The typical diffraction peaks of cellulose Ⅰ in as-spun fibers and precursors disappear, at the same time a new diffraction peak around 18.8° emerges, suggesting that new crystalline structure of as-spun fibers and precursors has formed. The typical diffraction peaks around 18.8° for precursors polymer strengthen, so crystallinity increases. Interestingly, the mass loss of as-spun fibers is 88.3%, and precursors is 60%, simultaneously the apparent activation energy increases from 31.31 kJ·mol^-1 of as-spun fibers to 39.18 kJ·mol^-1 of precursors, the thermal stability of precursors improves.