聚丙烯腈纤维预氧化前处理研究进展

综述了前人在聚丙烯腈原丝预氧化前处理方面的研究成果,介绍了前处理的作用机理及作用效果。研究发现,聚丙烯腈原丝的改性处理可显著提高纤维的结构和性能,并影响原丝在预氧化过程中的热力学和动力学,进而影响最终碳纤维的质量。     

Modification of polyacrylonitrile precursors for carbon fiber via copolymerization of acrylonitrile with ammonium itaconate

Ammonium‐modified polyacrylonitrile was prepared by free‐radical solution copolymerization of acrylonitrile (AN) with ammonium itaconate (AIA), and then it was spun into precursor fibers in this study. Effects of AIA and itaconic acid on the characteristics of the copolymers and precursor fibers were studied in contrast. It has been found that the ammonium modification could obviously increase the hydrophilicity of the copolymer. And in the spinning processes, modified copolymer can withstand higher total draw‐ratio of 12.6 folds, while unmodified copolymer only 8.5 folds. The void volume, fineness, tenacity, and elongation at‐break of the ammonium‐modified precursors are all improved and enhanced. WAXD test manifested that the modified precursors had higher degree of orientation. DSC test showed that the thermal properties of the modified and unmodified precursor fibers were almost the same. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 102: 2175–2179, 2006     

聚丙烯腈原丝预氧化过程中的结构与性能变化

综述了聚丙烯腈原丝在预氧化过程中的结构与性能变化规律,总结了预氧丝的表征方法。指出预 氧化过程中影响纤维结构与性能变化的主要因素有预氧化温度、预氧化时间和对纤维的拉伸倍数等。     

Preparation and characterization of carbon fibers from polyacrylonitrile precursors

The present work deals with the preparation of carbon fibers from polyacrylonitrile (PAN) fibers. The chemical composition and physical properties of the starting fibers were determined. The PAN fibers were stabilized in air at the temperatures (230, 270, and 300°C) with the heating time from 40 to 420 min. The effects of both final stabilization temperature and heating rate on the chemical and physical properties of the prepared stabilized fibers were studied. The chosen stabilized fibers samples were carbonized in argon atmosphere at the temperatures (1000, 1200, and 1400°C) with different heating rates 5, 10, 15, and 20°C min^?1. The effects of both carbonizing temperature and heating rate on the weight loss, density, elemental composition, and IR absorption spectra of carbonized fibers were also studied. The fiber sample, which was carbonized at 1400°C, contains 97.55% carbon, 1.75% nitrogen, and 1.4% hydrogen. This means that carbonizing the stabilized fibers at 1400°C in argon atmosphere is suitable to get oxygen‐free carbon fibers. Therefore, the used carbonizing temperature in the present work (1400°C) is suitable to produce moderate heat‐treated carbon fibers with the heating rate of 15°C min^?1. The modulus of the prepared carbon fibers was compared to that of industrially produced fibers using the results of X‐ray analysis. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

聚丙烯腈原丝的预氧化

主要阐述了预氧化反应的机理、改善预氧化的方法和与预氧化研究相关的表征技术,制备高性能碳纤维所需预氧丝的预氧化程度,以及预氧化工艺和预氧丝的表征参数与最终碳纤维性能的关系。     

化学改性对聚丙烯腈纤维及预氧纤维结构性能的影响

对聚丙烯腈纤维进行了化学改性,借助差示扫描量热分析（DSC）、定量傅立叶红外光谱（FT-IR）、平衡含水率、密度、力学性能等分析方法,对比研究了改性纤维、预氧化纤维、碳纤维与未改性纤维的结构性能的变化。研究表明：化学改性可促使聚丙烯腈纤维较未改性纤维初始环化反应温度前移,终止温度后移,从而有效缓解纤维在预氧化过程中的集中放热,有利于纤维结构和质量的控制;经硫酸羟胺改性后的纤维较未改性纤维制得的碳纤维抗拉伸强度提高16.3％。     

High‐temperature DSC study of polyacrylonitrile precursors during their conversion to carbon fibers

The evolution of structure, the changes of properties during the preoxidation, precarbonization, and carbonization of different polyacrylonitrile (PAN) precursors were firstly studied in detail by means of using high‐temperature differential scanning calorimetry (DSC) to characterize with continuous heating from 25 to 1400°C. It was essential to study the thermal behavior of PAN precursors so that proper temperature was determined. Three precursors with different composition, P1: acrylonitrile/itaconic acid (AN/IA) = 98/2 (wt/wt); P2: acrylonitrile/acrylamide (AN/AM) = 98/2 (wt/wt); P3: acrylonitrile/ammonium salt of itaconic acid (AN/AIA) = 98/2 (wt/wt) were, respectively, selected in this study. Comparative results of the DSC curves showed that the heating history influenced greatly the heat quantities released and exothermic position at low temperature of DSC curve, but influenced slightly at higher temperature. Aromatic index, carbon yield (W_c) and weight loss (η) can be calculated. After adjusting the temperature in preoxidation and precarbonization and carbonization technology depending on high‐temperature DSC, the high performance carbon fibers were obtained that tensile strength is 3.56–4.16 GPa, modulus is 235–243 GPa. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

氨化改性对IA-AN聚合及PAN原丝热性能的影响

研究了衣康酸和丙烯腈共聚时NH3的加入对聚合反应速率的影响 ,并借助DSC和TG等测试方法分析了氨化处理对聚丙烯腈原丝热性能的影响。结果表明 :单体浓度最好控制在 2 2 %左右 ,IA氨化改性后 ,与AN的共聚反应速率提高 ,纺丝液和原丝的亲水性能明显增加 ,NH3改性条件下原丝的热性能与改性前相差不大 ,尚不足以形成双峰     

突破原丝"瓶颈"是碳纤维产业化的必备条件

聚丙烯腈（PAN）原丝制约着碳纤维的质量、产量和价格,是碳纤维产业化的龙头老大。我国研究PAN基碳纤维已有30多年历史,至今未能产业化,其主要原因之一是我国PAN基原丝质量没有真正过关。所以,突破碳纤维产业化的原丝“瓶颈”已是当务之急。     

The formation of polyacrylonitrile nascent fibers in wet‐spinning process

The formation of polyacrylonitrile (PAN) nascent fibers in wet‐spinning process was studied by KMnO₄ back titration method and scanning electron microscopy (SEM). It has been found that the rate of DMSO diffusion was rapid at the beginning of coagulation then decreased and reached balance at 24 s. With coagulation time increase, the nascent fibers became denser and had fewer inner defects gradually, but transverse stripes appeared on the surface at 24 s, and got deeper. The main defects of nascent fibers included transverse stripes, impurity, fish tail, inner microvoids etc. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

高性能碳纤维原丝与油剂

油剂是生产高性能原丝和碳纤维的重要辅剂。它在单丝表面均匀成膜,既可防止单丝之间粘连和并丝,也可防止在生产过程中纤维表面与辊筒的摩擦与磨损,从而有效避免纤维表面产生缺陷,是提高原丝和碳纤维性能的有效技术措施之一。     

PAN基碳纤维原丝产品均质性研究

从纺丝生产工艺方面对聚丙烯腈(PAN)原丝产品均质化的影响因素进行了试验探讨。研究表明:优质的PAN原丝是碳纤维发展的基础,而均质化差的PAN原丝将导致原丝产品质量的性能缺陷及生产波动,极大的影响原丝的加工性能。     

PAN/PPG纤维预氧化及碳纤维结构和性能研究

采用聚丙二醇(PPG)与聚丙烯腈(PAN)共混制备的PAN/PPG原丝进行预氧化和碳化,利用SEM、FTIR、元素分析仪、力学性能测试等仪器和手段,研究了PPG的加入对预氧丝和碳丝的结构和性能的影响.研究发现:PPG的加入使PAN预氧丝的表面结构更加均匀,减少了碳纤维中的孔洞;同时还促进了纤维在预氧化和碳化过程中的氧化...     

Improving glass-fiber epoxy composites via interlayer toughening with polyacrylonitrile/multiwalled carbon nanotubes electrospun fibers

The development of innovative engineered epoxy composites aiming to manufacture cost-efficient materials with reduced weight and enhanced physical properties remains as a current industrial challenge. In this work we report an original procedure for manufacturing glass-fiber epoxy reinforced nanocomposites (GFECs) by employing electrospun fiber-mats as a reinforcing phase. These fibers have been produced from polyacrylonitrile and multiwalled carbon nanotubes solutions. Optimal protocols are designed by combining Taguchi method with the morphological, structural and mechanical properties obtained by scanning electron microscopy, profilometry and tensile tests. It is demonstrated that GFECs fabricated using GF800 glass fiber show an improvement/enhancement of the mechanical properties with a fracture strain up to 500 MPa (around 20% higher than the non-reinforced epoxy composite counterpart). It is also shown that GFECs fabricated using GF3M glass fiber exhibited a reduction of the roughness up to 56%, which corresponds with a roughness improvement from N8 to N7 following the guidelines provided by the ISO 1302. These results suggest that this type of nanocomposites would be suitable to be used in the aeronautics and automotive industries.     

四元共聚及氨化改性PAN原丝及其碳纤维研究

在工程线上进行了四元共聚及四元氨化改性聚丙烯腈(PAN)原丝及其碳纤维研制。采用浊点测试法表征了含磺酸基第四单体纺丝液的亲水性,并确定了其共聚含量;通过动态机械分析(DMA)和差示扫描量热分析(DSC)分别测试了氨化前后原丝的玻璃化转变温度(Tg)和预氧化特性。采用质量膨润度、原丝碘吸附量、结晶取向度、原丝体密度等表征了氨化前后四元共聚原丝的结构致密性。结果表明,氨化改性较磺酸基第四单体可显著提高四元共聚纺丝液的亲水性;红外光谱证明第四单体共聚于PAN分子链中;氨化后PAN原丝Tg升高约2.6℃,达到111.28℃;氨化未改变预氧化的峰顶温度。质量膨润度及原丝体密度表明氨化提高了原丝的致密性,但结晶取向度和原丝拉伸模量下降。工程线上碳纤维生产结果表明,四元氨化改性碳纤维强度>3 500 MPa的合格率较四元共聚的提高12%,达到90%,同时钩接强力也由四元的76 N提高到87 N。     

熔融纺丝工艺制备碳纤维原丝

聚丙烯腈基碳纤维的制备主要采用溶液纺丝方法,生产过程需要溶剂回收,工艺流程长,因此制造成本高。笔者主要介绍了聚丙烯腈基碳纤维的制备工艺概况,特别介绍了熔融纺丝路线制备聚丙烯腈原丝的方法。利用共聚改性、增塑改性、纺丝后处理等方法,可以制备聚丙烯腈基碳纤维,并提出了由熔融纺丝制备聚丙烯腈基碳纤维的可行路线。     

牵伸倍数分配对PAN原丝及其碳纤维力学性能影响

通过单变量试验,并结合取向度、表面电镜等对丝束性能检测,分析了PAN原丝生产中牵伸倍数分配对原丝及其碳纤维力学性能的影响。结果表明:原丝取向度的提高,主要取决于蒸汽牵伸倍数。随着蒸汽牵伸倍数的增加,分子链取向规整性增强,原丝的取向度得到提高,原丝的整体强度就会上升,其碳纤维的强度及模量也会随之提升。     

影响碳纤维用聚丙烯腈原丝水洗效果因素的探讨

水洗是碳纤维用聚丙烯腈（PAN）原丝生产过程中的重要环节,其效果好坏将直接影响碳纤维强度的高低。实验结果表明：在选择共聚单体组分时,要充分考虑共聚单体时聚合物亲水性的影响,有利于提高水洗效果;聚合物相对分子质量过高,会影响水洗效果;纺丝液中总固含量过大会增加水洗难度;采用梯度水温,外加浸洗与喷淋相结合方式对碳纤维用PAN原丝的洗涤效果较好,水的用量不会太大;对PAN纤维多段牵伸后水洗效果较好。     

PAN基高模碳纤维阳极氧化的表面处理

采用阳极氧化法对PAN基高模碳纤维进行连续表面处理,重点研究了氧化电流密度对碳纤维宏观力学性能、表面形貌、表面酸性官能团以及碳纤维增强树脂基复合材料(CFRP)层间剪切强度(ILSS)的影响。结果表明,电流密度对纤维力学性能、表面形貌影响不大;氧化后纤维表面总的酸性官能团显著提高,最大增幅达13倍左右;适当的处理条件可使CFRP的ILSS从28.4 MPa提高到80 MPa以上。     

聚丙烯腈原丝结构与性能的研究

采用日本聚丙烯腈原丝及国产聚丙烯腈原丝 ,通过纤维强度、伸长率、线密度、纤维相对分子质量和溶液性能等常规分析 ,以及 DSC、TG、IR分析 ,C、N、H元素分析 ,X射线和扫描电镜分析 ,找出日本原丝与国产原丝在强伸度、分子质量、元素含量、结晶度及其表面形貌等结构与性能的差别 ,从而为深入了解其结构与性能的关系和进一步提高我国原丝的质量提供科学依据。研究结果表明 :日本原丝较之国产原丝具有较高的断裂强度、较低的断裂伸长率 ,较高的分子质量、结晶度及取向度等优良性能。