静电纺丝法制备木质素纳米碳纤维的研究
发布时间：2018-11-12 10:07
【摘要】： 木质素是植物纤维原料主要成分之一,在自然界中蕴藏量仅次于纤维素。目前人类对木质素的利用还很不充分。由于木质素中含碳量较高(一般在55%～66%之间),因此可作为碳纤维原料进行利用。 本文以乙酸木质素及碱木质素为原料制备纳米碳纤维。首先采用静电纺丝法制备乙酸木质素纳米纤维,然后通过预氧化以及碳化处理得到木质素纳米碳纤维。采用THF, DMF,乙酸三种不同的溶剂对乙酸木质素进行静电纺丝。结果表明以乙酸为溶剂可以得到AAL纳米纤维,以THF以及DMF为溶剂不能电纺成纤。为了在碳化过程中保留纤维形态,需要对原纤维进行预氧化处理。结果发现,AAL纳米纤维的预氧化处理需要在空气氛围中在低于1℃/min的升温速率下进行。对AAL纤维的碳化处理在升温速率100℃/h的条件下,碳化温度需要低于700℃。对700℃碳化的纤维的结晶形态以及表面元素含量进行了分析。结果表明碳为无定形碳,碳含量86.7%,碳化不完全。 采用静电纺丝法制备了碱木质素纳米纤维,并讨论了电导率,溶液浓度,电压,极距,推速对碱木质素静电纺丝的影响。结果表明随着溶液质量分数的增加,纤维的直径显著增大。当溶液质量分数为40%以及45%时,随电压升高,纤维直径先增大后减小,在60kv时最小。推速增大,纤维直径显著增大。极距对纤维形貌没有影响,对纤维直径影响也不大。随极距增大,纤维直径先减小后增大。对碱木质素纳米纤维分别在500℃,600℃,700℃进行了碳化处理。分析了热处理过程中纤维直径的变化,发现纤维直径减小说明纤维在热处理过程中发生收缩。并对不同温度下碳化的纤维的结晶形态以及石墨化程度进行了分析。发现碳纤维均为无定形碳。随着碳化温度的升高,石墨化程度增加。
[Abstract]:Lignin is one of the main ingredients of plant fiber, which is second only to cellulose in nature. At present, human use of lignin is still very inadequate. Lignin can be used as carbon fiber because of its high carbon content (usually between 55% and 66%). Carbon nanofibers were prepared from lignin acetate and alkali lignin. Firstly, lignin nanofibers were prepared by electrospinning, and then lignin nanofibers were prepared by preoxidation and carbonization. The lignin of acetic acid was electrospun with three different solvents of THF, DMF, acetic acid. The results showed that AAL nanofibers could be obtained with acetic acid as solvent, while THF and DMF could not be electrospun into fibers. In order to preserve the fiber morphology during carbonization, preoxidation of the original fiber is needed. The results show that the preoxidation of AAL nanofibers needs to be carried out at a heating rate of less than 1 鈩，
本文编号：2326797
[Abstract]:Lignin is one of the main ingredients of plant fiber, which is second only to cellulose in nature. At present, human use of lignin is still very inadequate. Lignin can be used as carbon fiber because of its high carbon content (usually between 55% and 66%). Carbon nanofibers were prepared from lignin acetate and alkali lignin. Firstly, lignin nanofibers were prepared by electrospinning, and then lignin nanofibers were prepared by preoxidation and carbonization. The lignin of acetic acid was electrospun with three different solvents of THF, DMF, acetic acid. The results showed that AAL nanofibers could be obtained with acetic acid as solvent, while THF and DMF could not be electrospun into fibers. In order to preserve the fiber morphology during carbonization, preoxidation of the original fiber is needed. The results show that the preoxidation of AAL nanofibers needs to be carried out at a heating rate of less than 1 鈩，
本文编号：2326797
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