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在前文的基础上,研究了温度对超高分子量聚丙烯腈/二甲基亚砜溶液的零切粘度、流动曲线、非牛顿指数、最大松弛时间、结构粘度指数的影响,探讨了它们与溶液流动性、可纺性和挤出过程稳定性的关系.发现与常规分子量聚丙烯腈/二甲基亚砜溶液相比,其非牛顿指数和粘流活化能较小;而最大松弛时间却高出约三个数量级,因此当原液温度低于130℃时,流动曲线上不出现第一牛顿区.确定了溶液流动性、可纺性和挤出过程稳定性均较好的温度应不低于130℃,为纺制高强UHMW-PAN纤维和中空纤维膜提供了依据. 相似文献
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聚丙烯腈的原液组成与其可纺性和膜性能的关系 总被引:4,自引:0,他引:4
本文制备了含有添加剂的聚丙烯腈—二甲基亚砜浓溶液。研究了原液组成与膜的孔结构和超滤性能的关系。实验表明聚丙烯腈浓度、添加剂种类和含量对膜的孔隙率和平均孔径都有一定的影响,从而也影响其水通量和截留率。同时较系统地研究了聚丙烯腈浓度和添加剂含量对原液的非牛顿流动指数、结构粘度指数、零切粘度、剪切弹性模量和最大松弛时间的影响,探讨了它们与原液可纺性的关系。在此基础上,确定了能使原液的可纺性和膜性能都比较好的原液组成参数,并纺制成适合于超滤用的聚丙烯腈中空纤维膜。 相似文献
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UHMW—PAN中空纤维膜的研制及应用Ⅲ.温度对UHMW—PAN/DMSO溶液流变 … 总被引:2,自引:0,他引:2
在前文^「1~3」的基础上,研究了温度对超高一聚丙烯腈/二甲基亚砜溶液的零切粘度、流动曲线、非牛顿指数、最大松弛时间、结构粘度指数的影响,探讨了它们与溶液流动性、可纺性和挤出过程稳定性的关系。发现与常规分子量聚丙烯腈/二甲基亚砜溶液相比,其非牛顿指数和粘流活化能较小;而最大松弛时间却高出约三个数量级,因此当原液温度低于130℃时,流动曲线上不出现第一牛顿区。确定了溶液流动性、可纺性和挤出过程稳定性 相似文献
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以超高相对分子质量聚丙烯腈为原料 ,通过凝胶纺丝方法制备中空纤维膜。讨论了纺丝方法、相对分子质量和工艺条件 (纺丝原液浓度、气隙长度 )对中空纤维膜力学性能的影响 ;用 SEM测定了所制备的中空纤维膜的形态结构 相似文献
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超高分子量聚丙烯腈(UHMW PAN)在很多方面都有重要的作用。本文主要对聚合条件和反应机理进行了初步讨论。除此之外还研究了偶氮类引发剂引发的丙烯腈悬浮聚合,制备超高分子量聚丙烯腈的途径。本文还应用计算机模拟方法来寻找能够制备超高分子量聚丙烯腈的有效途径并用它来研究聚合反应动力学问题。 相似文献
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介绍了超高分子量聚乙烯的熔体特性,如粘度极高、熔体指数几乎为零、摩擦因数小、临界剪切速率低等。并介绍了超高分子量聚乙烯的模压成型,挤出成型,注塑成型,吹塑成型以及其他成型方法国内外研究的最新进展。也提到了对超高分子量聚乙烯进行改性以改善其加工性能。 相似文献
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PAN干湿法纺丝工艺中原丝的表面沟槽形态 总被引:4,自引:0,他引:4
徐梁华 《高科技纤维与应用》2001,26(2):21-24
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。 相似文献
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采用应力流变仪对聚丙烯腈/1-丁基-3-甲基咪唑氯化物(PAN/[BMIM]Cl)溶液体系的稳态和动态流变性能进行了研究,讨论了PAN相对分子质量(Mη)对溶液稳态和动态流变性能的影响。结果表明:PAN/[BMIM]Cl溶液在低剪切速率区表现出牛顿流体特征,在高剪切速率区随着剪切速率的增大粘度降低,表现为切力变稀流体;溶液的粘度大于常规溶剂体系,随着PAN的Mη增大,PAN/[BMIM]Cl溶液表观粘度明显增大,非牛顿指数减小,粘流活化能增大;溶液的损耗模量和储能模量越大,溶液更容易表现出弹性效应。 相似文献
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Characteristics of polyacrylonitrile solutions and fibers varied with the dissolution process in ionic liquid 下载免费PDF全文
The concentrated polyacrylonitrile (PAN) solutions were prepared with 1‐butyl‐3‐methylimidazolium chloride ([BMIM]Cl) as solvent by static state, stirring, and kneading. The steady and oscillatory shear tests were carried out to investigate the viscoelastic behaviors of the PAN/[BMIM]Cl solutions by rotational rheometer. It was found that the zero shear‐rate viscosity and relaxation time of the solution prepared by kneading were lowest and the non‐Newtonian index was largest among the solution. During kneading, the gelation temperature of the viscous and homogenous solution was at the lowest temperature 22.7°C among the all three solutions. Only the solutions prepared by stirring and kneading could be spun by dry‐jet wet spinning technology. The fiber processed with the solution prepared by kneading could be drawn with a higher draw ratio, showing the larger draw ability. The supramolecular structure and properties of the fibers were studied by synchrotron wide‐angle X‐ray diffraction (WAXD) technologies, dynamic mechanical analysis (DMA), and mechanical tests. All the results showed that the kneading is an efficient method for PAN fiber spinning with [BMIM]Cl as solvent. It lead to the investigation of the methods of preparation of PAN solution in [BMIM]Cl, which affect the homogeneity of the solutions and hence the resulting characteristics of PAN fibers. POLYM. ENG. SCI., 55:558–564, 2015. © 2014 Society of Plastics Engineers 相似文献
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为制备适于干 -喷湿纺用PAN(polyacrylonitrile)纺丝溶液 ,选用了较高粘均相对分子质量的PAN ,通过测定纺丝溶液的回转粘度 ,对其流变性能进行了较为详尽的研究。研究结果表明 :粘均相对分子质量为近 2 0万的PAN溶液为切力变稀型流体 ,具非牛顿性。在40~ 80℃的温度范围内 ,浓度为 18%~ 2 0 %的纺丝溶液的临界切变速率为 10 0 9~ 10 1 7。提高纺丝溶液的浓度可使溶液的粘流活化能 (Eη)及结构粘度指数 (Δη)增大、非牛顿指数 (n)减小 ;溶液温度升高则会导致n的增大和Δη的减小 相似文献
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KH550, KH560, CTAB, and F127 were adopted to modify silicon (Si) to improve the dispersity and stability of Si in the polyacrylonitrile/dimethyl sulfoxide (PAN/DMSO) polymer solutions. The influence of surfactants on rheological behaviors of PAN/DMSO/Si blending polymer solutions was investigated by an advanced solution and melt rotation rheometer. The homogeneity and stability were also studied. The results showed that the surfactants could change the viscosity dependence of blending polymer solutions on shear rate, temperature and storage time by increase the steric hindrance of Si. Among the four solutions, PAN/DMSO/Si blending polymer solution with F127 exhibited the lowest viscosity, activation energy and the smallest structural viscosity index and exhibited the trend close to the Newtonian fluids. Moreover, PAN/DMSO/Si blending polymer solution with F127 exhibited the best dispersity and stability, indicating its best physical properties and machinability. 相似文献
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Xiao-Hua Ma Yu Bai Yue Cao Zhen-Liang Xu 《Korean Journal of Chemical Engineering》2014,31(8):1438-1443
Porous stainless steel hollow fiber has been widely used due to its high mechanical strength, excellent thermal conductivity and good sealing properties compared with other porous supports. We successfully prepared porous stainless steel hollow fibers using polyacrylonitrile (PAN) as polymer via dry-wet spinning followed by sintering through temperature programming method. The PAN concentration had an obvious impact on the structure and property of porous stainless steel hollow fiber even if it would be burned off during sintering. The results showed that the morphology could be tuned by adjusting the concentration of PAN. With increasing PAN concentration in casting solution for spinning, the viscosity was increased dramatically, resulting in much compact structures with high pure water flux (higher than 3×105 L·m?2·h?1·Pa?1). A more dense structure could be obtained by adding additive polyvinylpyrrolidone (PVP) as viscosity enhancer. 相似文献