废聚丙烯腈纤维制备高性能碳纤维研究

针对国内碳纤维生产企业聚丙烯腈废丝问题进行高端循环再利用。采用紫外-可见分光光度计和旋转流变仪研究了二甲基亚砜/水混合溶剂对聚丙烯腈溶解能力和溶液流变性的影响,采用称重法研究了处理温度和时间对聚丙烯腈废丝脱水性能的影响,并利用废丝经溶解制备纺丝液、原丝和碳纤维。结果表明:水的存在影响了二甲基亚砜对聚丙烯腈的溶解能力,使聚丙烯腈溶液缠结增大,聚丙烯腈溶液的复数黏度、储能模量和损耗模量增加,聚丙烯腈纺丝液稳定性降低;提高处理温度和延长处理时间有利于聚丙烯腈废丝中水分的脱除,完全脱除水分的聚丙烯腈废丝经溶解、纺丝、预氧化和碳化,可以制备近似圆形、表面具有沟槽的T300级别聚丙烯腈碳纤维,碳纤维原丝生产线的废物得到绿色、高端化再利用。     

衣康酸氨化对聚丙烯腈基碳纤维聚合和原丝性能的影响分析

为制备力学性能优异的聚丙烯腈基碳纤维,采用氨化度不同的衣康酸(IA)单体与丙烯腈(AN)、丙烯酸甲酯(MA)和乙烯磺酸(AS)制备聚丙烯腈(PAN)基碳纤维。通过聚合转化率的测定表征聚合反应速度,显微镜观察原丝断面形貌,广角X射线衍射表征原丝结晶取向度,动态热机械法表征原丝的玻璃化转变温度和热收缩率,电子万能试验机表征原丝及碳纤维的力学性能。测试结果表明,IA经氨化后制备得到β-衣康酸铵,以β-衣康酸铵作为共聚单体制备的PAN纺丝液的数均相对分子质量达到64100,相对分子质量分布指数为2.96,比粘为1.86;纺丝后原丝断面明亮整齐,氨化度为25%的原丝在12倍牵伸下,单丝拉伸强度为6.8cN/dtex,弹性模量为113.0cN/dtex;该原丝的玻璃化转变温度较未氨化原丝提高了3.19℃;该原丝经炭化后的碳纤维(1K)的拉伸强度达到4572 MPa,弹性模量249GPa,钩结强力62.4N,纤维的力学性能和韧性得到提高。     

二元氨化聚丙烯腈碳纤维制备及性能的研究

以二甲基亚砜为溶剂,偶氮二异丁腈为引发剂,丙烯腈(AN)和氨化的衣康酸(IA)为聚合物单体进行二元自由基均相溶液聚合,合成了聚丙烯腈(PAN)纺丝溶液,经湿法纺丝制得PAN原丝,经预氧化和碳化得到氨化的PAN基碳纤维。采用扫描电镜、广角X射线衍射、动态机械法和电子万能机等表征方法对PAN原丝和PAN碳纤维的性能进行了表征。结果表明:IA经氨化后制得β-衣康酸,以β-衣康酸为聚合单体制备的二元PAN基原丝的拉伸性能更优异。     

UHMW-PAN中空纤维膜的研制及应用(4)--UHMW-PAN中空纤维膜的制备工艺

以超高相对分子质量聚丙烯腈(UHMW-PAN)为原料制备中空纤维膜,研究了纺丝方法和工艺条件对中空纤维膜力学性能的影响.实验表明,凝胶纺丝制备的中空纤维膜的韧性最好,其合适的工艺参数为:聚合物黏均相对分子质量Mv为1.29×106,纺丝溶液浓度C为3%,气隙长度L为3 cm,拉伸倍数R为14.     

超细高强PAN基碳纤维原丝纺丝液研究

聚丙烯腈的分子量越大,越有助于碳纤维超细高强高模化,但是由于纺丝液黏度急剧增大,以至于无法湿法纺丝,为解决这个问题,加入少量水来降低纺丝液的黏度.研究发现,高分子量聚丙烯腈-二甲基亚砜溶液中当水含量在1.5%～2%时,溶液黏度变得最低,且使纤维凝固成型缓和,结构均匀;同时还发现溶液粘度随温度升高而减小,当温度在65～8...     

用于碳纤维的聚丙烯腈原丝及其干湿法成型

介绍了用于碳纤维的聚丙烯腈原丝的发展历史 ,阐述了聚丙烯腈纺丝工艺中的主要工序和技术关键     

丙烯酸对聚丙烯腈原丝结构和热性能的影响

控制单体配比,采用丙烯腈（ＡＮ）与丙烯酸（ＡＡ）自由基熔液共聚,以偶氮二异丁腈为引发剂在溶剂二甲基亚砜中合成了聚丙烯腈原丝纺丝溶液,并纺制了碳纤维前驱体聚丙烯腈原丝。通过ＩＲ、ＤＳＣ、ＤＴＧ等手段,讨论了共聚单体ＡＡ对共聚物反应及聚丙烯腈原丝结构和热性能的影响。共聚单体ＡＡ能在较低温度时引发聚丙烯腈原丝的氧化、环化放热反应,且能减缓放热效应。Ｐ（ＡＮ－ｃｏ－ＡＡ）共聚物中共聚单体ＡＡ的摩尔分数控制     

碳纤维工艺技术研究及发展现状

根据基础原料不同,分别对聚丙烯腈(PAN)基碳纤维、沥青基碳纤维和粘胶基碳纤维的工艺技术特点进行了分析研究,重点对PAN基碳纤维原丝生产、预氧化、碳化和后处理过程进行了深入分析,探讨了共聚单体、纺丝工艺及杂质含量对PAN原丝性能的影响,以及原丝性能对PAN基碳纤维产品质量和生产成本的影响,并进一步阐述了PAN基碳纤维的国内外发展现状及研究方向。     

高性能碳纤维原丝聚合机理和纺丝工艺的研究

通过实践深入探讨了聚丙烯腈原丝生产的聚合机理，并借助于SEM对所纺的碳纤维原丝进行了探讨，实验证明，生产原丝中的聚合机理遵循4个阶段，而且聚合温度没有超过聚丙烯腈的分解温度。纺丝要控制预牵伸倍数在7左右，为蒸汽牵伸提高原丝的取向度和结晶度以及最终碳纤维的高性能作好准备。     

国内木质素基碳纤维生产技术的专利申请状况及问题分析

正1前言碳纤维是具有耐高温、耐腐蚀、高强度和低密度等特点的高性能纤维材料,在航天材料、汽车零件等领域得到了广泛应用。目前80%的商业碳纤维由聚丙烯腈制得,其中聚丙烯腈原丝成本占碳纤维总成本的一半,昂贵的原材料成本,在一定程度上限制了碳纤维在自动化工业领域的进一步推广[1]。     

纺丝液合成因素对木材液化物炭纤维原丝性能的影响

利用木材苯酚液化物合成纺丝液, 熔融纺丝制成新的炭纤维原丝, 研究了纺丝液合成因素对原丝性能的影响。试验结果表明: 增加合成纺丝液时液化原料中的苯酚/木材比(液固比), 则原丝的力学性能提高明显, 其中液固比由3增加至4时, 原丝拉伸强度增加了近9倍; 合成剂用量的增加却导致原丝力学性能的降低, 当合成剂用量为6%时, 原丝的拉伸强度和拉伸模量降幅较明显, 而断裂伸长率的最大降幅却出现在合成剂用量为4%时; 原丝的拉伸强度和拉伸模量随合成温度的升高而增加, 但增幅较小, 断裂伸长率随合成温度的升高却呈下降趋势, 且从110℃升高到115℃时断裂伸长率降幅较大; 原丝的力学性能随合成纺丝液升温时间的增加而先升高后降低, 升温时间为40min时制备的炭纤维原丝的力学性能最优。      

High‐Modulus Low‐Cost Carbon Fibers from Polyethylene Enabled by Boron Catalyzed Graphitization

Currently, carbon fibers (CFs) from the solution spinning, air oxidation, and carbonization of polyacrylonitrile impose a lower price limit of ≈$10 per lb, limiting the growth in industrial and automotive markets. Polyethylene is a promising precursor to enable a high‐volume industrial grade CF as it is low cost, melt spinnable and has high carbon content. However, sulfonated polyethylene (SPE)‐derived CFs have thus far fallen short of the 200 GPa tensile modulus threshold for industrial applicability. Here, a graphitization process is presented catalyzed by the addition of boron that produces carbon fiber with >400 GPa tensile modulus at 2400 °C. Wide angle X‐ray diffraction collected during carbonization reveals that the presence of boron reduces the onset of graphitization by nearly 400 °C, beginning around 1200 °C. The B‐doped SPE‐CFs herein attain 200 GPa tensile modulus and 2.4 GPa tensile strength at the practical carbonization temperature of 1800 °C.     

碳纤维形貌结构对其电化学氧化行为及其复合材料界面性能的影响

通过调控原丝工艺,制备得到形貌结构不同、力学性能相近的PAN基碳纤维(CF),用以模拟碳纤维表面光滑与沟槽结构对其电化学氧化行为的影响。研究表明:原始形貌光滑碳纤维在电化学过程中保持形貌能力较强,相同的电化学氧化强度下,其表面氧碳比高于原始表面粗糙的碳纤维,表明其氧化程度高。X射线光电子能谱(XPS)分峰结果表明,二者表面氧含量差别来自于表面羰基含量的差异。力学性能测试结果表明具有沟槽形貌的碳纤维拉伸强度及拉伸模量提高的幅度较大,其中拉伸强度提高最大值为17.3%。将氧化前后的碳纤维制备成碳纤维增强树脂基复合材料,探讨碳纤维形貌结构对其复合材料界面性能的影响。结果表明:由具有沟槽形貌的碳纤维制备得到的复合材料层间剪切强度(ILSS)较高,表明碳纤维表面物理形貌也是影响复合材料界面的重要因素。     

Structural features of polyacrylonitrile-based carbon fibers

The structural changes as functions of spinning conditions and heat treatments were investigated with respect to the structural feature of PAN-based carbon fibers by scanning tunneling microscopy (STM). The distinct granule structure on the cross section of both high tensile strength and high modulus carbon fibers was observed by SEM, while slender granule-shape domain on the longitudinal surface was revealed by STM. A structure model was proposed, which depicted that the PAN-based carbon fiber was a heterogeneous structure composed of aggregated mesostructural domains. These domains were closely arranged into spiral form along fiber axis, allowing the fibers have high strength and good elongation. The initial shape and size of domains was determined by the precursor composition and spinning conditions and also strongly depended on the heat-treated temperature and stretching conditions. The smaller or slender domain, the higher tensile strength obtained for fibers. We expect that the PAN-based carbon fiber with better performance should be produced by optimizing the size and shape of these domains.     

提高聚丙烯腈基炭纤维质量的方法

聚丙烯腈是炭纤维的重要原材料。高质量的聚丙烯腈才有可能生产出高质量的原丝,而高质量的原丝是保证高质量炭纤维的必在条件。聚丙烯腈的分子量及其分布、等规度、共聚结构单元的比例及分布上的缺陷直接影响着聚丙烯腈的质量,进而影响原丝及其炭纤维的性能。从调整聚丙烯腈分子量及分布、等规度、共聚结构单元的比例及分布入手,论述了提高聚丙...     

DSC Study on the Polyacrylonitrile Precursors for Carbon Fibers

Different polyacrylonitrile (PAN) precursor fibers that displayed various thermal properties were studied by using differential scanning calorimetry (DSC). Results showed that some commercial PAN precursor fibers displayed double separated peaks and these fibers were of high quality because of their process stability during their conversion to carbon fibers of high performance. Some fabrication processes, such as spinning, drawing, could not apparently change the DSC features of a PAN precursor fiber. It was concluded that the thermal properties of a PAN precursor fiber was mainly determined from its comonomer content type and compositions.     

原丝浸渍硼酸对炭纤维结构与性能的影响

聚丙烯腈原丝(3K,1.1dtex)用硼酸进行浸渍,再分别进行间歇式预氧化和炭化。借助元素分析、X射线衍射、红外分析和扫描电镜等表征手段和力学性能测试,研究了硼酸浸渍对原丝结构、预氧化炭化过程及炭纤维结构与性能的影响。结果表明,硼能进入到原丝的内部,但只是物理吸附,在浸渍过程中不改变原丝结构,在预氧化过程,硼钝化了纤维的环化、氧化反应,起始温度推迟2.5℃。在炭化过程中,硼促进了纤维结构的有序化和完善,炭纤维的强度和模量都得到了提高。硼质量分数为1.376×10-4,张力为108 g时,炭纤维抗拉强度为2544 MPa,较同等条件未渗硼的提高约90%。     

Hierarchical composites of carbon nanotubes on carbon fiber: Influence of growth condition on fiber tensile properties

Growing carbon nanotubes (CNT) on the surface of high performance carbon fibers (CF) provides a means to tailor the thermal, electrical and mechanical properties of the fiber–resin interface of a composite. However, many CNT growth processes require pretreatment of the fiber, deposition of an intermediate layer, or harsh growth conditions which can degrade tensile properties and limit the conduction between the fiber and the nanotubes. In this study, high density multi-wall carbon nanotubes were grown directly on two different polyacrylonitrile (PAN)-based carbon fibers (T650 and IM-7) using thermal Chemical Vapor Deposition (CVD). The influence of CVD growth conditions on the single-fiber tensile properties and CNT morphology was investigated. The mechanical properties of the resultant hybrid fibers were shown to depend on the carbon fiber used, the presence of a sizing (coating), the CNT growth temperature, growth time, and atmospheric conditions within the CVD chamber. The CNT density and alignment morphology was varied with growth temperature and precursor flow rate. Overall, it was concluded that a hybrid fiber with a well-adhered array of dense MWCNTs could be grown on the unsized T650 fiber with no significant degradation in tensile properties.     

PBO纤维的制备及性能研究

以4,6-二氨基间苯二酚盐酸盐-对苯二甲酸（DAR—TPA）盐为原料,多聚磷酸（PPA）为溶剂,制备了分子量较高的PBO聚合物纺丝液。通过液晶纺丝工艺制备PBO纤维,并对纺丝工艺对PBO纤维结构、性能的相关性影响进行了研究。研究结果表明,根据最优化条件制备的PBO纤维的拉伸强度为5．0GPa5．2GPa,拉伸模量为170GPa-180GPa,热分解温度为604℃,极限氧指数为67．9％。     

溶解法分级聚丙烯腈纤维精细结构

采用不同浓度的二甲基亚砜水溶液对聚丙烯腈(PAN)初生纤维进行溶解分级处理,利用紫外光谱定量研究溶解液中组分含量,凝胶渗透色谱、X射线衍射和差示扫描量热仪研究PAN初生纤维中不同组分的分子结构、结晶结构和热性质特性。研究结果表明,随着二甲基亚砜浓度的增加,溶解液的吸光度逐渐增大,说明可通过调整溶解能力将PAN纤维分成不同级分;未溶解PAN纤维的相对分子质量逐渐增大,(110)晶面(29°衍射)出现,表明纤维分子结构链段增长及规整性增加。说明进入低浓度溶液的组分,相对分子质量低且排列规整性差,反之亦然。采用溶解法可将干湿法PAN初生纤维结构逐次分级及定量,再结合常规纤维结构表征方法,可研究纤维更精细的结构。