净化沥青的傅里叶变换红外光谱分峰拟合定量分析

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朱亚明, 高丽娟, 赵雪飞, 吕君. 净化沥青的傅里叶变换红外光谱分峰拟合定量分析[J]. 光谱学与光谱分析, 2019,39(3): 765-771.
ZHU Ya-ming, GAO Li-juan, ZHAO Xue-fei, L#cod#x000dc; Jun. Quantitative Analysis of Refined Pitches by Curve-Fitting of Fourier Transform Infrared Spectroscopy Spectrum[J]. Spectroscopy and Spectral Analysis, 2019,39(3): 765-771.
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净化沥青的傅里叶变换红外光谱分峰拟合定量分析

朱亚明¹, 高丽娟¹, 赵雪飞^1,^*, 吕君^1,²

1. 辽宁科技大学先进煤焦化及煤资源高效利用工程研究中心, 辽宁鞍山 114051

2. 齐齐哈尔大学化学与化学工程学院, 黑龙江齐齐哈尔 161006

*通讯联系人 e-mail: zhao_xuefei@163.com

作者简介: 朱亚明, 1989年生, 辽宁科技大学先进煤焦化及煤资源高效利用工程研究中心博士研究生e-mail: zhuyaming0504@163.com

收稿日期: 2017-03-27

基金: 国家自然科学基金项目(U1361126), 教育部博士点基金项目(20132120110001), 辽宁省教育厅先进煤焦化及煤资源高效利用工程研究中心开放基金项目(USTLKFZD201503)资助

摘要

高温煤焦油沥青是人造炭材料的优质原料。为了获得高品质人造炭材料, 必须对原料沥青进行净化处理, 使得净化沥青具有合理的分子量分布、较高芳香缩合度和适宜的脂肪族侧链结构, 炭化后才能生成易于石墨化的趋于规整的碳微晶结构。分别以中温沥青和热聚合改性沥青为原料, 采用两种净化分离处理方法, 得到四种净化沥青(RP-1, RP-2, RP-3和RP-4)。以四种净化沥青的傅里叶变换红外光谱数据为基础, 结合分峰拟合数学方法, 准确获得了净化沥青的芳香性指数(Iar)、支链化指数(CH₃/CH₂)、 OH官能团的存在形式及分布情况和其他基础官能团含量。由分析研究结果可知, 四种净化沥青均具有较大的芳香缩合度。 RP-3芳香性指数高达0.90, 芳香缩合度最高。 RP-4支链化指数仅为0.07, 脂肪族侧链数量较多、碳链较长。四种净化沥青中OH官能团存在形式有明显不同。研究结果将为人造炭/石墨材料的原料优选提供理论支持。

关键词: 净化沥青; 傅里叶变换红外光谱; 分峰拟合; 定量分析

中图分类号:TQ522.6 文献标志码:A

Quantitative Analysis of Refined Pitches by Curve-Fitting of Fourier Transform Infrared Spectroscopy Spectrum

ZHU Ya-ming¹, GAO Li-juan¹, ZHAO Xue-fei^1,^*, LÜ Jun^1,²

1. Engineering Research Center of Advanced Coal Coking and Efficient Use of Coal Resources, University of Science and Technology Liaoning, Anshan 114051, China

2. College of Chemistry and Chemical Engineering, Qiqihar University, Qiqihar 161006, China

Abstract

High temperature coal tar pitch is a kind of high quality raw material to produce carbon materials. However, coal tar pitches without refining treatment was not suitable to produce such high quality carbon materials. Actually, refining treatment is an important way to adjust the molecular weight distribution, aromatic structure, and aliphatic side chain structure of coal tar pitch. Refining treatment is a precondition to produce carbon materials which is easy to graphitize with coal tar pitch as the raw material. In this study, four kinds of refined pitches numbered as RP-1, RP-2, RP-3 and RP-4 have been obtained by two kinds of preparation methods with the medium pitch and modified pitch as the raw materials, respectively. The refined pitches have been studied by Fourier Transform infrared spectroscopy (FTIR) and curve-fitting analysis in order to gain additional information on the comparation of these four refined pitches. The curve-fitted data provide quantitative evidence of aromaticity(Iar), length of aliphatic chain(CH₃/CH₂), distribution of OH groups, and oxygen-containing functional groups with different refined pitches. The results have showed that: these four kinds of refined pitches has a larger aromatic condensation degree. RP-3 has the highest aromaticity index of 0.9. RP-4 has the Index of the branched chain of 0.07, which means that RP-4 have a long aliphatic chain. The distribution of OH groups in refined pitches was significantly different. The results can provide a theoretical support for the selected raw materials in the preparation of carbon/graphite materials.

Keyword: Refined pitches; Fourier transform infrared spectroscopy; Curve-fitted analysis; Quantitative analysis

文章图片

引言

煤沥青是煤焦油加工过程中的副产品, 约占焦炭总产值的2.4%~3.6%^[1]。也是生产一系列人造炭材料和石墨材料的重要前驱体^{[2, 3, 4]}。例如, 煤沥青被广泛用于生产针状焦^{[5, 6]}, 碳纤维^{[7, 8]}, 以及包覆沥青^[9](主要用于锂离子电池负极材料的包覆剂)。但是, 由于沥青中含有大量的喹啉不溶物(QI)而不能直接用于这些材料的生产。因此, 以煤沥青为前驱体制备人造炭/石墨材料之前, 需对煤沥青进行净化处理, 以除去沥青中的QI。目前, 常用的脱除QI的方法有以下几种^{[10, 11]}: 溶剂过滤法, 溶剂重力沉降法, 离心法, 和静电场法。在众多沥青净化方法中, 最常用的脱除QI的方法是溶剂热过滤法和溶剂重力沉降法。被脱除QI的沥青通常被称作净化沥青。

检测物质的官能团结构是研究复杂混合物(如煤及其衍生物)最通用的一种分析技术^[12]。近年来研究者们发现利用分峰拟合所特有的分离重叠峰的特点, 结合FTIR光谱数据可以更为准确的定量分析诸如煤等复杂物质中各官能团的含量, 对复杂化合物的性质的判定有更好的帮助^{[13, 14]}。

利用傅里叶变换红外光谱结合分峰拟合的数学方法对通过溶剂萃取沉降法和溶剂萃取热过滤法获得的四种净化沥青的芳香性指数(Iar)、支链化指数(CH₃/CH₂)、并各官能团分布情况进行了定量分析。对制备的几种净化沥青作为高性能炭材料前驱体的可行性进行了初步判断。

1 实验部分

1.1 原料

中温沥青由山西焦化厂提供; 热聚合改性沥青由将中温沥青在一定条件下进行热缩聚反应得到; 甲苯(北京化工厂); 喹啉(天津瑞金特化工有限公司)。

1.2 净化沥青的制备

编号为RP-1, RP-2, RP-3和RP-4的四种净化沥青通过不同的净化分离方法得到。其中, RP-1和RP-2是以中温沥青为原料, 分别通过溶剂重力沉降法和溶剂热过滤法得到; RP-3和RP-4则是以热聚合改性沥青为原料, 分别通过溶剂重力沉降法和溶剂热过滤法制得。

1.3 沥青的工业分析

几种沥青的工业分析严格按照国家标准执行检测。其中, 软化点(SP)是通过环球法测得(ASTM E28); 甲苯不溶物(TI)参考GB/T 2292— 1997标准进行; 喹啉不溶物(QI)参考GB/T 2293— 1997标准进行测试; 结焦值(CV)依据GB/T 2727— 88标准测试。四种净化沥青的工业分析如表1所示。

表1 净化沥青的工业分析 Table 1 Proximate analysis of refined pitches

1.4 FTIR光谱分析

净化沥青的FTIR光谱测试在FTIR/NIR光谱仪上进行(PerkinElmer Spotlight-400), 测试之前, 需将样品和KBr严格按照质量比为1 mg∶ 150 mg的比例混合压片处理。通过对波长为3 000~2 700和900~700 cm^-1吸收峰进行分峰拟合处理, 以波长和吸光度的积分面积为基础, 较为准确的计算出了脂肪族氢和芳香族氢的含量。通过分峰拟合处理可以计算出波长为1 800~1 000 cm^-1区间内的含氧官能团分布情况, 以及3 700~3 000 cm^-1区间内羟基官能团的分布情况^[14]。文献[14]报道的FTIR光谱中, 各官能团的归属如表2所示。

表2 FTIR光谱中官能团的归属 Table 2 Band wavenumbers and assignments in the FTIR spectra

1.5 分峰拟合分析

分峰拟合处理是对FTIR重叠峰进行有效分离从而获得每个吸收峰面积的一种非常有效的方法。对相应重叠峰进行分峰拟合处理所用的数据处理软件是常见的Orign Pro/Orign Lab Corporation软件。在选定的FTIR区间内, 吸收峰个数和吸收峰位置通过对该区间内的FTIR数据进行二阶导数得到, 拟合过程中, 所有的拟合吸收峰均为高斯拟合。为了提高拟合的准确度, 拟合过程中需达到以下标准: 确定系数(COD)大于0.999, 标准误差参数(chi-squared)小于10^-5。

2 结果与讨论

2.1 净化沥青的FTIR光谱定性分析

净化沥青的FTIR谱图如图1所示。由图1可以看出在300~2 700 cm^-1区间内的脂肪氢吸收峰的吸光度从RP-1到RP-4呈现逐次增加的趋势; 图1中, 四种样品中含氧官能团的区别最大(1 800~1 100 cm^-1), 并且, 热过滤方法得到的净化沥青(RP-2, RP-4)比沉降法得到的净化沥青(RP-1, RP-3)中C=O官能团要多; 四种净化沥青中, 芳香氢(900~700 cm^-1)也有明显的区别。

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	图1 各净化沥青的FTIR谱图Fig.1 FTIR spectrum of refined pitches

2.2 净化沥青的FTIR定量分析

为了更准确的对四种净化沥青的官能团含量进行判定, 利用FTIR光谱和分峰拟合相结合的方法对样品进行了研究, 以获得更充足的结构参数信息。计算过程中选取的特征区间为3 700~3 100, 3 000~2 800, 1 800~1 000和900~700 cm^-1(参照表2), 拟合峰中, 波数与吸光度的积分面积用于各结构参数的计算。其中, 支链化指数(CH₃/CH₂)和芳香性指数(Iar)参照式(1)和式(2)进行计算。

$\begin{array}{l} C H_{3} / C H_{2} = Abs \cdot 2950 c m^{- 1} band / \\ Abs \cdot 2920 c m^{- 1} band (1) \\ Iar = Abs \cdot 3050 c m^{- 1} / (Abs \cdot 3050 c m^{- 1} + \\ Abs \cdot 2920 c m^{- 1}) (2) \end{array}$

式(1)是— CH₃的吸收峰积分面积和— CH₂— 的吸收峰面积的比值, 该参数可以用来准确的判定煤及其衍生物的支链长度和支链的多少^[14]。式(2)用于拟合峰的面积来准确计算净化沥青的芳香性。

2.2.1 净化沥青中OH形成的氢键分布情况

文献[14, 15]报道, 煤及其衍生物在为3 700~3 100 cm^-1的区间内的吸收峰主要是6个官能团的吸收峰的叠加造成的(如表2所示), 其中, 有5个吸收峰归属于OH官能团形成的氢键结构。图2(a, b, c, d)分别是四种净化沥青在波数为3 700~3 100 cm^-1区间内的分峰拟合图。图3是净化沥青中OH官能团的氢键结构分布情况。

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	图2 区间3 700~3 100 cm^-1的FTIR拟合谱图 (a): RP-1; (b): RP-2; (c): RP-3; (d): RP-4Fig.2 The curve-fitted IR spectra of 3 700~3 100 cm^-1 zone (a): RP-1; (b): RP-2; (c): RP-3; (d): RP-4

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	图3 各净化沥青的OH官能团分布Fig.3 The distribution of OH groups in refined pitches

由图3可以看出, RP-1中OH官能团形成的氢键结构主要是以羟基自缔合氢键为主(含量达41.71%), 其次是羟基-π 氢键(含量为23.93%), 环状缔合羟基氢键的含量最少(含量仅为9.68%); RP-2则主要是以羟基-π 氢键为主(含量高达51.52%), 其次为羟基-醚氧氢键(含量为25.17%); RP-3则是以羟基-π 氢键和羟基-醚氧氢键为主(含量分别为34.25%和30.00%), 羟基自缔合氢键含量次之(含量为25.04%); RP-4中羟基官能团形成的氢键结构分布情况与RP-1有着相类似的趋势, 主要是以羟基自缔合氢键为主(含量为38.92%), 并且各羟基官能团含量相对较为平均。

2.2.2 净化沥青的脂肪氢结构分布情况

图4(a, b, c, d)分别是四种净化沥青的FTIR光谱在波长为3 000~2 700 cm^-1脂肪氢区间内的分峰拟合结果。具体的峰位置和归属见表2。众所周知, 在波数为2 950和2 920 cm^-1处的FTIR吸收峰分别是由— CH₃的不对称伸缩振动和— CH₂— 的不对称伸缩振动造成的。另外, 在此脂肪氢区间内还可拟合成另外的三个吸收峰, 即— CH₃和— CH₂— 的对称伸缩振动吸收峰(分别在2 879和2 853 cm^-1处), 以及2 896 cm^-1处的次甲基C— H伸缩振动。相应的拟合数据结果见表3所示。

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	图4 各净化沥青在3 000~2 800 cm^-1区间内的分峰拟合谱 (a): RP-1; (b): RP-2; (c): RP-3; (d): RP-4Fig.4 Curve-fitted IR spectra of the 3 000~2 700 cm^-1 zone (a): RP-1; (b): RP-2; (c): RP-3; (d): RP-4

表3 各净化沥青的结构参数 Table 3 Structural parameters of refined pitches

由表3可以看出四种净化沥青的芳香性指数(Iar)和支链化指数(CH₃/CH₂)明显不同。 RP-3的Iar和CH₃/CH₂数值均为最大(依次为0.90和0.40), 说明RP-3的芳香缩合度最高, 并且脂肪侧链的数量最少, 链长最短, 说明RP-3主要是以芳香族稠环为主。相对于相同原料来源的RP-3, RP-4的结构性质与之迥异, RP-4的CH₃/CH₂指数最小(仅为0.07), 说明RP-4中脂肪侧链的含量很多, 并且链较长。 RP-2的结构组成与RP-3类似, 主要是以芳香性稠环为主, 而脂肪侧链较少, 而RP-1的脂肪侧链的数量和长度均要高于RP-2。

2.2.3 净化沥青的含氧官能团分布情况

四种净化沥青在波长为1 800~1 000 cm^-1区间内拟合谱图分别如图5(a, b, c, d)所示, 该区间内主要是含氧官能团的吸收峰叠加而成的, 相应的官能团含量分布情况如图6所示。

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	图5 1 800~1 000 cm^-1区间内的FTIR拟合谱图 (a): RP-1; (b): RP-2; (c): RP-3; (d): RP-4Fig.5 Curve-fitted FTIR spectrum of the 1 800~1 000 cm^-1 zone (a): RP-1; (b): RP-2; (c): RP-3; (d): RP-4

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	图6 基础官能团分布Fig.6 Distribution of primary functional groups

由图5(a, b, c, d)和表2可以看出, 净化沥青在1 800~1 000 cm^-1区间内的官能团主要归属于C=O, C=C, C=O和C— O官能团, 并没有— COOH官能团的出现。也就是说, 净化沥青中C=O官能团主要是酯类和酮类官能团结构。

图6是四种净化沥青在1 800~1 000 cm^-1区间内的基础官能团分布情况。可以看出, RP-1中C=C官能团含量为43.14%, 而C=O和C— O官能团含量依次为29.28%和27.58%。 RP-2中, C=C , C=O和C— O官能团的含量依次为46.22%, 19.84%和33.94%。 RP-3中基础官能团主要是以C=O为主, 含量达到46.10%, 而RP-4中三种官能团含量依次为: 32.27%, 34.45%和33.28%, 各官能团分布较为平均。

2.2.4 净化沥青的芳香氢分布情况

净化沥青在900~700 cm^-1区间内的FTIR吸收峰是由于芳环C— H的面外振动造成的, 按芳环上H的个数可以分为三种: 芳环面上孤立的H(870 cm^-1左右)的吸收峰, 芳环上相邻两H(815 cm^-1左右处)的吸收峰和芳环上四H(750 cm^-1左右处)的吸收峰^{[14, 15]}。在此区间内, 四种净化沥青的FTIR分峰拟合情况结果如图7(a, b, c, d)所示, 相应的分峰拟合计算数据如表4所示。

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	图7 900~700 cm^-1区间内的FTIR拟合谱 (a): RP-1; (b): RP-2; (c): RP-3; (d): RP-4Fig.7 Curve-fitted FTIR spectrum of the 900~700 cm^-1 zone (a): RP-1; (b): RP-2; (c): RP-3; (d): RP-4

表4 芳香C— H面外振动的拟合结果 Table 4 Evolution of the aromatic C— H out-of-plane deformation zone^a

表4可以看出四种净化沥青中, 三类芳香环上H的分布情况各不相同。四种净化沥青中, RP-3中芳环上1H的含量最少(为53.78%), 说明侧链取代最少, 支链越多; 而RP-4中芳环上1H的含量最多(为62.71%), 说明侧链取代最多, 支链最多。另外, RP-3中4H/5H的含量高达22.46%, RP-2的含量紧随其后为21.76%, 说明RP-3的芳香缩合度最高, RP-2次之, 这与之前的芳香性指数Iar和支链化指数CH₃/CH₂分析结果相一致。

3 结论

(1)沥青的来源和净化方法的选择对获得的净化沥青的性质有重要的影响。 RP-1, RP-2, RP-3和RP-4的芳香性指数均大于0.6, 净化沥青的芳香性稠环结构较多; RP-4的支链化指数CH₃/CH₂仅为0.07, 说明其脂肪侧链数量和长度最多, RP-3的芳香性指数高达0.90, 说明其芳香缩合度最高, 芳环数最多。

(2)对净化沥青的OH官能团分析可知, RP-1中OH官能团形成的氢键结构主要是以羟基自缔合氢键为主(含量达41.71%), RP-2则主要是以羟基-π 氢键为主(含量高达51.52%), RP-3则是以羟基-π 氢键和羟基-醚氧氢键为主(含量分别为34.25%和30.00%), RP-4中羟基官能团形成的氢键结构分布情况与RP-1有着相类似的趋势, 主要是以羟基自缔合氢键为主(含量为38.92%)。另外, 四种净化沥青的基础官能团C=C, C=O 和C— O)含量得到了较为准确的计算。

(3)FTIR光谱结合分峰拟合的数学方法可以准确定量分析净化沥青中各官能团的含量, 为高性能炭材料的前驱体沥青的选择提供了一种更准确的判定方法。

The authors have declared that no competing interests exist.

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2015

0.0

... 6%^[1] ...

2012

0.0

... 也是生产一系列人造炭材料和石墨材料的重要前驱体^[2,3,4] ...

2016

0.0

XIAO

Nan

, QIU

Jie-shan

(肖南, 邱介山). Chemical Industry and Engineering Progress(化工进展), 2016, 35(6): 1804.

Coal tar pitch is abundant as a byproduct of coke production in iron-steel industry in China. However,the traditional methods cannot efficiently convert coal tar pitch into value-added products and how to make effective use of coal tar pitch remains a big challenge. This review has summarized several techniques for further processing of coal tar pitch,with a focus on the synthesis and applications of high performance functional materials including mesophase pitch, porous carbons,carbon fibers,two dimensional nano-sized carbon materials and carbon based composites. This review highlights that the strong π-π interactions between highly condensed polycyclic aromatic molecules in coal tar pitch is the bottle-neck that hinders the efficient conversion of coal tar pitch into functional carbon materials with tuned structure and properties. The molecular structure and properties of coal tar pitch can be improved through catalytic condensation,oxidization or co -pyrolysis. With coal tar pitch as precursor,methods including templating, physical/chemical activation, surface induction and catalytic graphitization have been developed for the controlled synthesis of high performance carbon materials. Novel methods that can tune the molecular structure of coal tar pitch are highly demanded to improve the performance of coal tar pitch based carbon materials and related researches should be intensified.

State Key Laboratory of Fine Chemicals, Liaoning Key Laboratory for Energy Materials and Chemical Engineering, Dalian University of Technology, Dalian 116024, Liaoning, China

我国煤沥青资源丰富,但深加工技术落后,产品附加值低,实现煤沥青高附加值利用是亟待解决的重大课题。本文介绍了以煤沥青为原料合成高性能功能碳材料的主要技术,重点阐述了以煤沥青为原料制备中间相沥青、多孔碳材料、碳纤维、二维纳米碳材料及碳基复合材料的研究进展。分析表明,高芳香性和高缩合度分子结构所引起的强π-π相互作用是阻碍煤沥青基高性能功能碳材料设计合成的瓶颈问题。通过催化聚合、氧化、共热解等技术手段可有效改善煤沥青分子结构及其物理、化学性质。结合模板复制、物理/化学活化、界面诱导以及催化石墨化等技术可实现多种功能性碳材料结构设计与表面化学性质调控。发展煤沥青分子结构调控新技术作为改善煤沥青基碳材料性能的重要策略,需要系统深入研究。

... 也是生产一系列人造炭材料和石墨材料的重要前驱体^[2,3,4] ...

2016

0.0

TANG

Xian-yi

, WEI

Xiao-hui

, XU

De-ping

, et al(唐闲逸, 魏晓慧, 许德平). Chinese Journal of Materials Research(材料研究学报), 2016, 30(6): 448.

The carbonization in a tube bomb of medium-temperature coal tar pitch and the purified coal tar pitch, of which quinoline insoluble (QI) had been removed by anti-solvent method, was comparatively studied. The results show that coal tar pitch with high QI contents could not be suitable for preparation of needle coke of high quality. However, the coke which was obtained through carbonization under 0.2 MPa at 500℃ for 10 h had a relatively lower coefficient of thermal expansion (CTE). The QI could be removed effectively by anti-solvent method when kerosene and wash oil were mixed as solvents. By a precipitation process at 100℃ and precipitation time for 4 h with the ratio of wash oil to kerosene was 0.4 and stirring for 0.5 h, the QI contents of the refined coal tar pitch could be reduced to 0.0914% and 0.0695% for the ratios of solvents to coal tar pitch as 1.8 and 2 respectively. The needle coke which were prepared by such refined coal tar pitch showed lower CTE after being carbonized at 500℃, by 0.2 MPa and for 10 h.

1. School of Chemistry& Environmental Engineering, China University of Mining & Technology (Beijing), Beijing 100083, China 2. Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China 3. Heilongjiang Institute of Science and Technology, Harbin 150022, China

以中温煤沥青为原料, 研究其在弹管反应器中的炭化以及“反溶剂法”脱出喹啉不溶物(QI)后的精制沥青的炭化效果。结果表明: 含有较高QI的非精制沥青不能制备出较好的针状焦, 但在500℃, 0.2 MPa, 10h的炭化条件下, 能够得到相对较优热膨胀系数(CTE)的炭化结果; 以煤油和洗油为混合溶剂, 反溶剂法能够有效地脱除喹啉不溶物, 在芳脂比0.4, 沉降温度100℃, 搅拌时间0.5 h, 沉降时间4 h, 溶剂比1.8、2的条件下, QI含量分别降到0.0914%和0.0695%, 将其在500℃、0.2 MPa、10 h的条件下炭化, 可制备出热膨胀系数(CTE)较低的针状焦。

... 也是生产一系列人造炭材料和石墨材料的重要前驱体^[2,3,4] ...

2011

0.0

SUN

Quan

, WANG

Bao-cheng

, ZHANG

Huai-ping

, et al(孙权, 王保成, 张怀平, 等). New Carbon Materials(新型炭材料), 2011, 26(6): 429.

The influence of a magnetic field during thermal polycondensation and carbonization of intermediate coal tar pitch on the electrical conductivity of the resulting needle cokes was explored using a pressure vessel under an external magnetic field. The microstructure of the cokes was analyzed by X-ray diffraction and polarized light microscopy. The electrical conductivity was measured during the coke forming process. Results indicated that aromatic molecules were ordered under the magnetic field during carbonization, leading to an improvement in the microcrystalline structure and an increase in the electrical conductivity of the cokes. Resistance-temperature curves also indicated that the magnetic field can accelerate the polymerization rate and reduce the dependence of the polymerization on temperature, which can be explained by the Zeeman effect.

College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024|China

以中温煤沥青为原料，在载磁压力反应釜中进行热缩聚炭化合成针状焦；采用在线电阻测量法测定针状焦形成过程中磁场对电导的影响规律；通过偏光显微镜及X射线衍射仪对产物的形貌和组织结构进行表征。结果表明: 外加磁场对于改善针状焦微结构具有显著的作用，并能有效提高针状焦的电导特性，减小制备过程对温度的依赖性；适宜的压力有利于热缩聚反应的进行，提高成焦的收率；磁场还可以通过塞曼效应对自由基产生影响，提高自由基有效利用率，加快聚合反应速率；在磁场与压力的协同作用下，针状焦的石墨化性能也获得大幅度提升。