高模量碳纤维的现状及发展(2)

主要介绍了国内外聚丙烯腈基和沥青基高模量碳纤维的研究现状及发展趋势。⑴高模量碳纤维的发展方向:1980年代,两大高模量碳纤维都朝着高强高模方向发展,以满足飞机主承力结构件高强高模并重的需要,因而促使高模量碳纤维的性能从单一高模化向高强高模化方向迈进,如东丽公司的M50J和M60J的抗拉伸强度(σ)分别为4.12 GPa和3.92 GPa,抗拉伸模量(E)分别为475 GPa和588 GPa,与M50(σ:2.45 GPa,E:490 GPa)相比均大幅度提高;1990年代率先研制出XN-70(σ:3.3 GPa,E:690 GPa)和FT-700(σ:3.3 GPa,E:700 GPa)沥青基高强高模碳纤维产品不久,美国AMOCO公司也生产出Thorne K-1000(σ:3.1 GPa,E:956 GPa)商品,满足了工业界的需求。⑵原丝的品质是提升高强高模碳纤维性能的关键:人们特别关注聚合物单体、溶剂、环境等的净化,以及聚合纺丝工艺参数的选择和调整,目的是如何能生产出低灰份杂质,细直径,高碳收率,高取向度和结晶度,毛丝少,柔韧性好,均匀稳定的优质原纤维。优质原纤维是制备高强高模的物质基础。⑶热处理制备工序、设备选型及工艺参数的调控也是提高高强高模碳纤维性能不可或缺的条件:人们在热处理过程用DSC-TG(热分析仪)、EA(元素分析仪)、FE-SEM(场发射扫描电镜)、HRTEM(高分辨透射电镜)、XES(X-射线能谱仪)、XRD(X-射线衍射仪)、Raman(拉曼光谱)、NMR(核磁共振仪)、STM(原子力显微镜)和AAS(原子吸收光谱)等先进的测试分析方法以及万能材料试验机等,研究各工序的工艺参数对产品性能和结构的影响,并详细的用图表阐述之。前人研究的成果加速了世界高强高模碳纤维性能的提升。进而提出了提高我国高强高模碳纤维的关键技术(例如研制非硅系新油剂,加强各工序的净化度和设备加工精度,强化工艺参数调控精度和加强灵活可变性,分析测试的准确度和测试方法的统一性等)。同时简介了高模量碳纤维的应用领域和前景。     

高模量碳纤维的现状及发展(1)

主要介绍了国内外聚丙烯腈基和沥青基高模量碳纤维的研究现状及发展趋势。⑴高模量碳纤维的发展方向:1980年代,两大高模量碳纤维都朝着高强高模方向发展,以满足飞机主承力结构件高强高模并重的需要,因而促使高模量碳纤维的性能从单一高模化向高强高模化方向迈进,如东丽公司的M50J和M60J的抗拉伸强度(σ)分别为4.12 GPa和3.92 GPa,抗拉伸模量(E)分别为475 GPa和588 GPa,与M50(σ:2.45 GPa,E:490 GPa)相比均大幅度提高;1990年代率先研制出XN-70(σ:3.3 GPa,E:690 GPa)和FT-700(σ:3.3 GPa,E:700 GPa)沥青基高强高模碳纤维产品不久,美国AMOCO公司也生产出Thorne K-1000(σ:3.1 GPa,E:956 GPa)商品,满足了工业界的需求。⑵原丝的品质是提升高强高模碳纤维性能的关键:人们特别关注聚合物单体、溶剂、环境等的净化,以及聚合纺丝工艺参数的选择和调整,目的是如何能生产出低灰份杂质,细直径,高碳收率,高取向度和结晶度,毛丝少,柔韧性好,均匀稳定的优质原纤维。优质原纤维是制备高强高模的物质基础。⑶热处理制备工序、设备选型及工艺参数的调控也是提高高强高模碳纤维性能不可或缺的条件:人们在热处理过程用DSC-TG(热分析仪)、EA(元素分析仪)、FE-SEM(场发射扫描电镜)、HRTEM(高分辨透射电镜)、XES(X-射线能谱仪)、XRD(X-射线衍射仪)、Raman(拉曼光谱)、NMR(核磁共振仪)、STM(原子力显微镜)和AAS(原子吸收光谱)等先进的测试分析方法以及万能材料试验机等,研究各工序的工艺参数对产品性能和结构的影响,并详细的用图表阐述之。前人研究的成果加速了世界高强高模碳纤维性能的提升。进而提出了提高我国高强高模碳纤维的关键技术(例如研制非硅系新油剂,加强各工序的净化度和设备加工精度,强化工艺参数调控精度和加强灵活可变性,分析测试的准确度和测试方法的统一性等)。同时简介了高模量碳纤维的应用领域和前景。     

高模量炭纤维的现状及发展

沈曾民,迟伟东,张学军等撰文介绍了国内外聚丙烯腈基和沥青基高模量炭纤维的研究现状和发展趋势。（1）高模量炭纤维的发展方向：20世纪80年代,两大高模量炭纤维都朝着高强高模方向发展,以满足飞机主承力结构件高强高模并重的需要,因而促使高模量炭纤维的性能从单一高模化向高强高模化方向迈进,     

高温石墨化对碳纤维结构的影响

使用高温石墨化炉对实验室自制的高强中模碳纤维进行连续石墨化处理,制备得到了强度4.86 GPa、模量541 GPa的高强高模碳纤维,并详细研究了石墨化处理过程中主要工艺参数对碳纤维结构与性能的影响。研究结果探讨掌握了高温石墨化(2 500℃)处理前后碳纤维微观结构的演变规律。     

国产碳纤维增强树脂基复合材料的界面结合性能研究

研究了国产高强中模碳纤维T800、高模碳纤维M50J及M55J的力学性能及其增强树脂基复合材料的界面结合强度(ILSS),并与日本东丽公司同级别碳纤维进行对比。结果表明:国产M55J碳纤维的拉伸模量为568 GPa,拉伸强度为4.50 GPa,日本东丽公司M55J的拉伸模量为561 GPa,拉伸强度为4.10 GPa,国产高模碳纤维表面石墨化程度高于日本东丽碳纤维,表面呈现更高惰性,其增强树脂基复合材料的ILSS略低于日本东丽碳纤维复合材料;将高强中模碳纤维与高模碳纤维混合后对树脂基体进行增强,混合碳纤维中随着高强中模碳纤维含量提高,其复合材料的ILSS提高幅度也随之增加。     

低温石墨化对碳纤维性能的影响

使用高温石墨化炉对实验室自制的高强中模碳纤维进行连续石墨化处理,制备得到了强度4.86 GPa、模量541 GPa的高强高模碳纤维,并详细研究了石墨化处理过程中主要工艺参数对碳纤维结构与性能的影响。研究结果探索掌握了低温石墨化(1 600~2 200℃)过程中,不同处理温度对碳纤维密度、拉伸强度、拉伸模量等性能的影响规律。     

高模PAN基碳纤维在北京化工学院碳纤维工程研究中心试制成功

最近该中心已突破了高模量聚丙烯腈基碳纤维的技术难关,试制出了相当于M40型号的2公斤高模碳纤维,经测试模量约为390GPa,强度为2.7GPa,延伸度约0.6％。     

宁波材料所成功制备高强高模碳纤维M60J

正近日,宁波材料所在国产高强高模碳纤维关键制备技术方面取得重要进展,制备得到拉伸强度5.24 GPa、拉伸模量593 GPa的高强高模碳纤维,实现国产M60J关键制备技术的突破。高强高模碳纤维具有拉伸模量高、热膨胀系数小、     

辽宁诺科碳材中间相沥青基碳纤维实现量产

<正>辽宁诺科碳材料有限公司以石油产重芳烃为原料,致力于高模量(高导热、低成本)中间相沥青基碳纤维及其复合材料的研发生产。目前该公司实现了中间相沥青工业生产技术突破,并掌握了中间相沥青的熔纺技术及氧化、碳化、石墨化工艺等核心技术。诺科碳材如今已实现中国自己的中间相沥青基碳纤维量产:一期工程"20 t/a高模(高导热)中间相沥青     

M60J高强高模碳纤维关键制备技术获突破

<正>2018年3月20日,中国科学院宁波材料技术与工程研究所制备出拉伸强度5.24 GPa、拉伸模量593 GPa的高强高模碳纤维,实现了国产高强高模碳纤维M60J关键制备技术的突破。2016年1月,宁波材料所在国内率先实现国产M55J制备技术重大突破,同年9月进行了制备技术验证,并获得拉伸强度4.15 GPa、拉伸模量585 GPa的高强高模碳扦维。后续研究进一步实现了国产M55J高强高模碳纤维连续稳定生产,纤维主体性能批间批内离散系数<5%。     

Processing,structure, and properties of gel spun PAN and PAN/CNT fibers and gel spun PAN based carbon fibers

Polyacrylonitrile (PAN) and PAN/carbon nanotube (PAN/CNT) fibers were manufactured through dry‐jet wet spinning and gel spinning. Fiber coagulation occurred in a solvent‐free or solvent/nonsolvent coagulation bath mixture with temperatures ranging from ?50 to 25°C. The effect of fiber processing conditions was studied to understand their effect on the as‐spun fiber cross‐sectional shape, as well as the as‐spun fiber morphology. Increased coagulation bath temperature and a higher concentration of solvent in the coagulation bath medium resulted in more circular fibers and smoother fiber surface. as‐spun fibers were then drawn to investigate the relationship between as‐spun fiber processing conditions and the drawn precursor fiber structure and mechanical properties. PAN precursor fiber tows were then stabilized and carbonized in a continuous process for the manufacture of PAN based carbon fibers. Carbon fibers with tensile strengths as high as 5.8 GPa and tensile modulus as high as 375 GPa were produced. The highest strength PAN based carbon fibers were manufactured from as‐spun fibers with an irregular cross‐sectional shape produced using a ?50°C methanol coagulation bath, and exhibited a 61% increase in carbon fiber tensile strength as compared to the carbon fibers manufactured with a circular cross‐section. POLYM. ENG. SCI., 55:2603–2614, 2015. © 2015 Society of Plastics Engineers     

High strength and high modulus carbon fibers

Carbon fibers have been processed from gel spun polyacrylonitrile copolymer on a continuous carbonization line at Georgia Tech (GT) with a tensile strength in the range of 5.5–5.8 GPa, and tensile modulus in the range of 354–375 GPa. This combination of strength and modulus is the highest for any continuous fiber reported to date, and the gel spinning route provides a pathway for further improvements in strength and modulus for mass production of carbon fibers. At short gauge length, fiber tensile strength was as high as 12.1 GPa, which is the highest value ever reported for a PAN based carbon fiber. Structure analysis shows random flaws of about 2 nm size, which results in limiting tensile strength of higher than 20 GPa. Inter-planar turbostratic graphite shear modulus in high strength carbon fibers is 30 GPa, while in graphite the corresponding value is only 4 GPa.     

Preparation of carbon fibers from linear low density polyethylene

Carbon fibers were produced from linear low density polyethylene (LLDPE) instead of commonly used precursors, such as viscose rayon, mesophase pitch and polyacrylonitrile (PAN). Cross-linked fibers were produced at various temperatures, times and stress conditions during a sulfuric acid treatment using LLDPE fibers obtained from dry-wet spinning. The effects of cross-linking were analyzed using a range of characterization techniques, such as differential scanning calorimetry, color change, fourier transform infrared spectroscopy, elemental analysis, density, scanning electron microscopy, and single filament mechanical properties. The carbonization process of cross-linked fibers was carried out at 950 °C for 5 min in a nitrogen atmosphere. The carbon fibers with the best mechanical properties were obtained from the cross-linked fiber with the highest tensile modulus. In particular, the carbon fibers with the best mechanical properties (tensile strength and tensile modulus of 1.65 GPa and 110 GPa, respectively), similar to commercial-grade carbon fiber, were obtained from the cross-linked fiber that had undergone a carbonization process with a stress of 0.25 MPa after an acid treatment for 150 min at 140 °C and a stress of 0.26 MPa.     

Gel-spun carbon nanotubes/polyacrylonitrile composite fibers. Part III: Effect of stabilization conditions on carbon fiber properties

The oxidative stabilization process of gel-spun carbon nanotube (CNT)/polyacrylonitrile (PAN) composite fibers have been studied and optimized. Optimum stabilization time depends on both the applied tension and temperature. Various characterization methods including thermal shrinkage, dynamic mechanical analysis, infrared spectroscopy, and wide angle X-ray diffraction are used to monitor the chemical and structural evolution during stabilization and carbonization. The relationship between the stabilization conditions of CNT/PAN composite fiber and the tensile properties of the resulting carbon fibers were investigated. By optimizing stabilization conditions, CNT/PAN based carbon fibers with a tensile strength of 4 GPa and a tensile modulus of 286 GPa were obtained using batch carbonization processing at 1100 °C.     

Wet-spinning assembly of continuous and macroscopic graphene oxide/polyacrylonitrile reinforced composite fibers with enhanced mechanical properties and thermal stability

Polyacrylonitrile (PAN) composite microfibers with different contents of graphene oxide (GO) were fabricated via wet-spinning route in this work. Based on nonsolvent-induced phase separation theory, N,N-dimethyl formamide/water mixture system was employed as coagulation bath, nonsolvent (water) diffused into PAN spinning solution and led to a quick PAN fiber solidification. Nematic liquid crystal state of GO dispersions and GO/PAN spinning solutions were determined via polarized optical microscopy images, and the morphology and structure of the composite fibers were characterized via scanning electron microscope, Transmission electron microscopy, Fourier transform infrared spectra, and X-ray diffraction. 1 wt % GO/PAN composite fibers exhibited outstanding mechanical properties, 40% enhancement in tensile strength and 34% enhancement in Young's modulus compared with pure PAN fiber. The results of dynamic mechanical analysis indicated that the composite fiber with 1 wt % GO performed the best thermal mechanical property with 5.5 GPa and 0.139 in storage modulus and loss tangent, respectively. In addition, thermogravimetric analysis showed that thermal stability of the composite fibers enhanced with the increasing GO contents. GO/PAN composite fibers can be as the candidate of carbon fiber precursor, high performance fibers, and textiles applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 46950.     

煤加氢热解沥青制备通用级沥青碳纤维的研究

以煤加氢热解沥青为原料,采用空气氧化和氮气吹扫处理,制备了可纺沥青,收率超过70％。可纺沥青经过纺丝、预氧化和炭化,制得通用级沥青碳纤维。实验结果表明,沥青碳纤维直径12．2um、抗拉强度623MPa、模量30．5GPa、伸长率2．05％。     

Correlation between fibril structures and mechanical properties of polyacrylonitrile fibers during the dry-jet wet spinning process

The high quality polyacrylonitrile (PAN) fibers, which were used to manufacture the high performance carbon fibers, were prepared by the dry-jet wet spinning process. The fiber samples were treated by using the ultrathin sectioning and solution etching methods. Subsequently, the changes of the fibril structures and mechanical properties were investigated by utilizing scanning electron microscopy, high-resolution transmission electron microscopy and mechanical tester. The fiber titer and diameters, the amount of the pores decreased during the spinning process. The microfibrils were oriented along the fiber axis to form the fiber backbone in PAN fibers. Furthermore, the microfibrils with small size were incorporated into the large fibrils and some fold chains formed the interfibril transverse joint bridges to reinforce the connection of the fibril elements. The fibrils served as self-reinforcing element to efficiently resist the cracks propagation and dissipate much energy to increase the tensile strength and initial modulus. Consequently, the PAN precursor fibers with the homogeneous, compact, well-oriented, and closely interlinked fibrils, presented high tensile strength and initial modulus. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47336.     

大直径中间相沥青基炭纤维的制备研究

以萘系中间相沥青为原料,通过熔融纺丝和随后的预氧化、炭化以及石墨化处理制备了中间相沥青基圆形炭纤维.研究了热处理温度对纤维导电性能和力学性能的影响,并采用红外光谱仪、元素分析仪、扫描电子显微镜和X射线衍射仪对纤维的组成、形貌和微观结构进行了表征.研究结果表明：纤维在预氧化时形成的羟基、酰基等含氧官能团在随后的炭化、石墨化处理过程中消失;随热处理温度的升高,石墨微晶逐渐发育、长大,并沿纤维轴向高度取向,纤维的电阻率不断降低,力学性能不断增强;3 000℃石墨化纤维电阻率为1.3μΩ·m,对应的强度和模量值为1.6GPa和380 GPa.     

PAN基高模量碳纤维成型过程中的结构性能关联性

以实验室自制T800级聚丙烯腈（PAN）基高强中模碳纤维为原料，经连续石墨化处理得到M50J级、M55J级高模量碳纤维，以X射线衍射（XRD）、Raman光谱为表征手段研究了高强碳纤维向高模量碳纤维转变过程中石墨微晶、取向、微孔含量、石墨化度等石墨特征结构的演变规律，并开展了PAN基碳纤维石墨特征结构与力学性能的关联性研究。研究结果表明：在高强碳纤维向高模量碳纤维转变过程中，随着石墨微晶层间距d ₀₀₂的下降以及石墨微晶堆砌厚度L _c的增加，碳纤维的拉伸模量逐渐提升；石墨微晶层间距和微晶取向是影响碳纤维拉伸强度的两个主要因素，石墨微晶层间距d ₀₀₂值增加、石墨微晶取向越高，纤维拉伸强度也越高；在高模量碳纤维的成型过程中，纤维内部微孔含量随着石墨化程度的提高而降低；经过高温石墨化处理后，碳纤维的拉伸强度会随着Raman光谱中无序结构D峰和石墨特征结构G峰积分强度比值I _D /I _G的下降而下降。