静电纺丝复合滤材制备及性能研究

研究了纺丝液浓度对聚丙烯腈(PAN)静电纺丝纤维直径,以及对PAN静电纺丝纳米纤维膜复合滤材过滤性能的影响。测试结果表明,纺丝液浓度增加,静电纺丝纤维直径变粗,孔径增大,其中质量分数为16%的纺丝液具有良好的纺丝性能,静电纺丝所得的纳米纤维直径均匀,复合后滤材在颗粒直径0.3μm,过滤风速5.3 cm/s的测试条件下,过滤效率达到99.98%,阻力为138 Pa,达到H13级别,具有高效低阻特性。     

磁场辅助静电纺PAN纳米纤维有序度的研究

采用磁场辅助静电纺丝法制备了有序聚丙烯腈(PAN)纳米纤维,分析了PAN/二甲基甲酰胺(DMF)溶液浓度、纺丝电压、注射速度、磁铁间距和溶剂DMF及DMF与二甲基亚砜(DMSO)混合溶剂等因素对PAN纤维有序度的影响。结果表明:随着PAN/DMF溶液中PAN浓度增大,PAN纤维有序度逐渐增大;注射速度对纤维有序度影响不明显;随着纺丝电压和磁铁间距增大,PAN纤维有序度先增大后减小;DMSO的加入,使溶液可纺性降低,不利于纤维有序排列;对于PAN/DMF溶液体系,适宜的磁场辅助静电纺丝的工艺参数为PAN质量分数12%,纺丝距离12 cm,电压14 k V,注射速度0.5 m L/h,磁铁间距2.5 cm,纺丝得到的PAN纳米纤维的有序度为92%。     

超大长径比双螺杆挤出机制备聚丙烯腈初生纤维

采用自主研发的超大长径比(136)双螺杆挤出机实现了PAN初生纤维的纺丝制备,研究了PAN粉料质量分数(16%、20%、24%)、双螺杆挤出机机筒温度(50、60、70℃)、循环挤出次数(0、1、2)对PAN初生纤维力学性能及表面形貌的影响。结果表明,PAN初生纤维的拉伸强度随质量分数、机筒温度和循环挤出次数的增加而增大;PAN初生纤维的断裂伸长率随质量分数和循环挤出次数的增加而减小,随机筒温度的升高而增大;随着循环挤出次数增加,纤维表面越来越规整,缺陷逐渐减少。研究结果为利用超大长径比双螺杆挤出机制备出性能更好的PAN初生纤维奠定了基础。     

PAN干湿法纺丝工艺中原丝的表面沟槽形态

本文在研究了PAN溶液粘度特性的基础上,研究了纺丝液粘度特性与相关组成因素间的关系,初步探讨了不同纺丝工艺在纤维表面结构形成过程中的作用,实验表明,溶液粘度随PAN质量分数和相对分子质量的增加而增大,温度是调控体系粘度的有效方法;同时纺丝液中PAN质量分数的提高,有利于提高纤维的致密性并促使凝固牵伸倍数和总牵伸倍数增大,而干湿法纺丝技术在消除纤维表面沟槽方面有独特的作用。     

沸水再拉伸速率对聚丙烯腈纤维结构与性能的影响

以1-丁基-3-甲基咪唑氯盐([BMIM]Cl)为溶剂溶解聚丙烯腈(PAN)制成PAN纺丝原液,采用干喷湿法纺丝,经过凝固、预拉伸、沸水拉伸制得PAN纤维,对所得PAN纤维进行沸水再拉伸处理,研究了沸水再拉伸速率对PAN纤维结构和性能的影响。结果表明:PAN纤维中残留质量分数为4.38%的离子液体,为沸水再拉伸起到了增塑作用;随着沸水再拉伸速率的增大,PAN纤维的力学性能提高,断裂强度由2.69cN/dtex提高到4.33 cN/dtex,而断裂伸长率由26%减小到20%,纤维的玻璃化转变温度、晶区取向度、双折射率、结晶度、晶粒尺寸均增大。     

溶液参数对静电纺丝PAN@PS复合纳米纤维形貌及结构的影响

采用同轴静电纺丝技术,以聚丙烯腈(PAN)溶液为核层、聚苯乙烯(PS)溶液为壳层,制备了PAN@PS复合纳米纤维。研究了纺丝液浓度、溶剂种类对PAN@PS复合纳米纤维形貌和结构的影响。结果表明:PS/四氢呋喃(THF)作为壳层溶液的复合纳米纤维(PAN@PS/THF)可获得相界面清晰的同轴纤维。随PS纺丝液浓度的增加,纤维的直径先增大后有所减小,整体呈现递增的趋势,当PS/THF质量分数为20%时,纤维直径约为693 nm且表面光滑。而以质量分数为20%的PS/二甲基甲酰胺(DMF)为壳层溶液的复合纳米纤维(PAN@PS/DMF)直径有所增加且纤维表面凹凸不平,呈现双相连续的结构。因此,在静电纺丝过程中,可以通过改变纺丝液的参数来调节纤维的形貌和结构。     

纺丝液流变行为对烟用二醋酸纤维性能的影响

为优化二醋酸纤维素(CDA)纤维的纺丝加工成型工艺,对CDA丙酮纺丝液的流变行为及所纺纤维的表面形貌和力学性能进行了测试。分析质量分数对纺丝液的流变行为的影响并研究纺丝液流变行为与所纺纤维直径及力学性能之间的关系。结果表明:随着CDA质量分数的提高,纺丝液黏度增大,所纺纤维直径增大,纤维强度下降,断裂伸长增大;对于不同特性黏度、质量分数但流变行为相近的纺丝液所纺纤维的直径、力学性能相近;降低二醋片的特性黏度,适当提高纺丝液的质量分数,可实现在保证产品质量的前提下,减少生产成本,提高纺丝速率。     

反应性挤出制备PP-g-PEGA调温纤维的研究

以过氧化二异丙苯(DCP)为引发剂,通过反应性挤出的方法将相变材料丙烯酸聚乙二醇酯(PE-GA)接枝到聚丙烯(PP)基体上,利用熔融纺丝的方法制备PP-g-PEGA调温纤维。通过红外光谱法和溶剂萃取法表征了PEGA在PP上的接枝情况;通过差示扫描量热仪、纤维强力仪和扫描电镜分别表征了PP-g-PE-GA调温纤维的储热性能、力学性能和外观形态。结果表明:PEGA与PP发生了化学接枝,PP-g-PEGA纤维的接枝率达3.2%;当PEGA的质量分数为8.0%,引发剂DCP质量分数为0.6%时,相变焓达6.93 J/g;PP-g-PEGA调温纤维的断裂强度随着PEGA含量的增加呈先增大后减小的趋势;PP与PEGA相容性良好,纤维的外观光滑均匀。     

次氯酸钠处理多孔PAN纤维的结构与吸附性能研究

以聚丙烯腈/聚乙烯吡咯烷酮/二甲基亚砜(PAN/PVP/DMSO)三元体系为纺丝液,以DMSO/H_2O为凝固浴,在凝固浴温度为60℃下,通过湿法纺丝制备了具有介孔结构的多孔PAN/PVP纤维;用次氯酸钠(NaClO)对多孔PAN/PVP纤维进行处理,制得了NaClO@PAN/PVP纤维,采用场发射扫描电镜、元素分析仪和氮气气体吸附仪对处理前后纤维的表面形貌、元素组成、比表面积和孔径进行了表征,研究了凝固浴浓度和温度对PAN/PVP纤维和NaClO@PAN/PVP纤维的PVP含量及比表面积和孔径的影响。结果表明:经NaClO处理后,NaClO@PAN/PVP纤维中氧含量减少,氮含量增多,PVP含量减少,纤维表面变得光滑,平均孔径减小,孔数增多,比表面积增大;随着凝固浴DMSO浓度增大或温度升高,PAN/PVP纤维,NaClO@PAN/PVP纤维中的PVP含量降低,但其比表面积随凝固浴浓度的增大而减小,随凝固浴温度的升高而先升高后减小;在凝固浴DMSO质量分数为0,温度为60℃的条件下制得的PAN纤维、PAN/PVP纤维、NaClO@PAN/PVP纤维的比表面积分别为38,96,108 m~2/g,平均孔径分别为22.7,20.4,19.0 nm;PAN/PVP纤维、NaClO@PAN/PVP纤维的最可几孔径分布在40 nm左右,属于介孔结构。     

CPCM/PP蓄热调温纤维的制备及表征

采用熔融复合纺丝法,通过自制的复合纺丝组件,以聚丙烯(PP)为皮层,由脂肪酸酯类和高级酯肪族醇类组成的复合相变材料(CPCM)为芯层,制备了具有皮芯结构的CPCM/PP蓄热调温纤维,并对纤维的结构与性能进行表征。结果表明:CPCM/PP初生纤维呈皮芯结构,其直径约为100μm;当CPCM/PP质量比为55∶45时,其初生纤维在70℃下5倍拉伸后,得到的CPCM/PP蓄热调温纤维中CPCM的质量分数为53.63%,熔融相变温度与结晶相变温度分别为32.65~48.02℃和20.96~39.02℃,熔融焓和结晶焓分别为90.04,81.01 J/g,纤维线密度为10.3 dtex,断裂强度为2.59 cN/dtex,断裂伸长率为41.38%。     

凝胶染色过程中腈纶沿纺程的结构性能变化的研究

采用湿法纺丝工艺制备腈纶(即聚丙烯腈(PAN)纤维),研究了凝胶染色过程中PAN纤维在不同工序段的结构和物理性能。结果表明:沿着纺程,PAN纤维的直径逐渐减小,纤维的玻璃化转变温度和结晶度逐渐提高;在水洗后PAN纤维表面有明显的微观结构缺陷、且无定形区占比高;经过热拉伸和干燥致密化之后,纤维致密化,结晶度大大增加,凝胶染色后的PAN纤维染色均匀,且色泽良好,成品PAN纤维对羊毛、PAN纤维、聚酯纤维、尼龙纤维、棉纤维、醋酯纤维的沾色牢度为4~5级;PAN纤维力学性能沿纺程变化主要取决于纺程上各工序的工艺变化,凝胶染色不影响纤维的断裂强度和断裂伸长率。     

水对PAN-DMSO溶液流变性能及纺丝成形的影响

研究了水对聚丙烯腈-二甲基亚砜(PAN-DMSO)纺丝溶液流变性能和初生纤维组成及双扩散系数的影响。随着水含量的增加,PAN-DMSO溶液的表观粘度有所下降,其流动性得以改善,粘流活化能下降,孔口胀大比变大。适量水的加入还降低了纺丝成形过程中溶剂、非溶剂的扩散速率,减少了纤维中水含量,有利于制备高性能PAN原丝。     

Carbon fibers derived from wet‐spinning of equi‐component lignin/polyacrylonitrile blends

Equi‐component blends of polyacrylonitrile (PAN) and lignin, i.e., with a lignin content as large as 50 wt %, were successfully used as precursors to produce carbon fibers. Rheological measurements demonstrated that increasing lignin content in spinning solution reduced shear viscosity and normal stress, indicating a decrease of viscoelastic behavior. This was confirmed by Fourier transform infrared results that show no discernable chemical reaction or crosslinking between PAN and lignin in the solution. However, the resulting carbon fibers display a large I_D/I_G ratio (by Raman spectroscopy) indicating a larger disordered as compared to that from pure PAN. The macro‐voids in the lignin/PAN blend fibers typically generated during wet‐spinning were eliminated by adding lignin in the coagulant bath to counter‐balance the out‐diffusion of lignin. Carbon fibers resulting from lignin/PAN blends with 50 wt % lignin content displayed a tensile strength and modulus of 1.2 ± 0.1 and 130 ± 3 GPa, respectively, establishing that the equi‐component wet‐spun L/P‐based carbon fibers possessed tensile strength and modulus higher than 1 and 100 GPa. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45903.     

含纳米负离子的聚丙烯腈原液的特性研究

主要探讨了纳米负离子在聚丙烯腈溶液中的分散问题,并讨论了纳米粉体对聚丙烯腈相对分子质量、溶液流变特性的影响。结果表明:添加顺序对纳米级负氧离子粉体在聚丙烯腈干法纺丝原液中的分散有很大影响,在溶胀前加入纳米负离子粉体的分散效果最佳;随着粉体含量的增加,分散效果降低,粉体含量<3%时分散性较好;负离子粉体的加入使得原液的黏度有所降低,黏流活化能有所增加;但在较高剪切速率下,黏度随温度的变化不明显,且黏流活化能也接近常规PAN原液。     

碳纳米管对聚丙烯腈溶液流变行为的影响

将混酸处理后的多壁碳纳米管(MWNT)超声分散于含5%水的二甲基亚砜(DMSO)中,然后将其与聚丙烯腈(PAN)/DMSO(含5%水)的纺丝溶液剪切共混,制备含碳纳米管的PAN纺丝溶液。采用椎板旋转流变仪研究了PAN纺丝溶液的流变行为。结果表明,添加碳纳米管后,PAN纺丝溶液的表观粘度变大,且其对剪切速率的敏感性增强。同时,随着MWNT含量的增加,PAN纺丝溶液的非牛顿指数降低,结构粘度指数和粘流活化能增大。     

Characteristics of wet‐spun and thermally treated poly acrylonitrile fibers

The performance of carbon fibers depends on the quality of the precursor and the conditions of the thermal treatment. In detail, for a PAN precursor fiber the viscosity of a spinning dope and the draw ratio during the spinning process needs to be considered. Through wet spinning, different types of PAN precursor fibers with defined spinning parameters, including solid content, solvent content in a bath, and especially draw ratio resulting in defined cross section diameters, were fabricated and analyzed with tensile tests, density investigations, SEM, TGA‐MS, FTIR, and XRD. The results show that the mechanical properties of the fibers correlate to crystallinity. The cross section diameter is strongly related to the morphology of the fibers after thermal treatment. By extending the postdrawing of PAN fibers high tenacities were obtained at the cost of the cross section shape. In addition, TGA measurements reveal trapped residues of the wet spinning process as well as show several chemical reactions takes place at the same time at different temperatures. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43698.     

Structural and thermal property changes of plasticized spinning polyacrylonitrile fibers under different spinning speeds

The effect of the spinning speed on structural and thermal properties of polyacrylonitrile (PAN) fibers prepared by plasticized spinning was investigated. The PAN fibers were characterized by scanning electron microscopy, X‐ray diffraction, differential scanning calorimetry, and thermogravimetric analysis. We found that the surface morphology of the fibers was relatively smooth. The presence of a small amount of surface defects was caused by the instability of spinning process. The final fibers may have had two tensile fracture modes, that is, cluster breaking and axial split fracture. The structure of the as‐spun fibers was destroyed when the spinning speed was up to 500 m/min; this led to chain scission in the amorphous region. The final fibers exhibited mechanical properties that were roughly comparable to those of commercial PAN fibers. The changing trend in the cyclization temperature of the final fibers was consistent with that of crystallinity, which first increased and then decreased. The decomposition temperature in the amorphous region increased with increasing spinning speed. The decomposition temperature in the crystalline region increased with increasing crystallinity. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45267.     

聚丙烯腈/凹凸棒土纺丝溶液的流变行为

将纳米凹凸棒土(AT)加入聚丙烯腈(PAN)/二甲基亚砜(DMSO)纺丝溶液中,用平板流变仪研究了温度、AT含量对纺丝溶液流变性能的影响。结果表明:随着AT含量的提高,纺丝溶液的表观黏度及结构黏度指数降低,非牛顿指数和粘流活化能增大。     

Preparation of antimicrobial polyacrylonitrile fibers: Blending with polyacrylonitrile-co-3-allyl-5,5-dimethylhydantoin

Summary Polyacrylonitrile-co-3-allyl-5,5-dimethylhydantoin (Cop7-1) was prepared by a free radical polymerization process. The copolymer was blended with polyacrylonitrile (PAN) in a NaSCN aqueous solution, and the mixture was employed as a spinning solution. Rheological behavior of the spinning solution was studied. The PAN/Cop7-1 blend fibers were prepared through a two-stage wet spinning process. Tensile strengths of the blend fibers were lightly lower, but breaking elongations were higher than regular PAN fibers. Moisture regain and antistatic properties of the blend fibers were improved, while the thermal stability of the blend fibers decreased slightly. However, after treatment with 1% regular chlorine bleach, the blend fibers showed good antibacterial ability.