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采用一步水热还原法制备了多壁碳纳米管(MWCNTs)/还原氧化石墨烯(r GO)纳米杂化材料,进一步通过溶液混合方法将纳米杂化材料与氨纶混合制备了氨纶/MWCNTs/r GO(NCs)溶液,使用旋转流变仪研究了NCs溶液浓度和温度对其静、动态流变行为的影响。结果表明,高浓度的NCs溶液黏度对剪切速率较为敏感,产生明显的剪切变稀现象,但在低剪切速率下其黏度仍有较宽的稳定平台;随温度降低,浓度为10%的NCs溶液黏度升高,剪切变稀现象更为明显,当温度低于60℃时,黏度的稳定平台变窄;NCs溶液在角频率较低时具有较好的纺丝性能,角频率大于200 rad/s时,储能模量高于损耗模量,纺丝时容易造成出口胀大堵塞纺丝孔,对于纺丝不利;NCs溶液的非牛顿指数随着温度升高而升高,与剪切变稀随温度升高而减弱的现象一致。由静、动态流变测试结果综合分析,浓度为10%的NCs溶液适宜纺丝的温度应该大于60℃,剪切速率应低于20 s-1。 相似文献
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应用多元回归分析确定了相对分子质量、温度、剪切速率、浓度4种主要因素对干喷湿纺聚丙烯 腈/二甲基亚砜(PAN/DMSO)纺丝原液粘度的影响。研究发现,纺丝原液粘度随着相对分子质量、浓度的增 大而增高,且过了临界相对分子质量、临界浓度后粘度会急剧增大。实验测得相对分子质量为7.8×104的 溶液临界浓度为11.5%。纺丝原液粘度随着温度、剪切速率的增大而降低,过了临界切变速率后粘度会急 剧下降,但在低剪切速率区粘度基本不变。通过多元线性回归模型,得出了多因子复合流变方程。 相似文献
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采用简易式毛细管流变仪、高聚物浓溶液动态粘弹仪和显微摄影技术,在模拟实际纺丝工艺条件下,测定了氨纶(PU)原液的稳态和动态流动曲线、孔口膨化比,重点研究了PU原液温度对其粘弹性的影响。研究结果证明,PU原液为切力变稀流体,结构粘度指数(Δη)、剪切弹性模量(G)均随温度升高而下降,在30—50℃范围内,Δη与G的变化甚微,这表明氨纶可在室温下纺丝,增加原液温度不仅使可纺性更佳,且有利于提高纺速,从而制得细旦氨纶。 相似文献
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为了获得力学性能优异的聚酰亚胺纤维,将含咪唑单元的2-(二氨基苯基)苯并咪唑-5胺引入到以3,3’,4,4’-联苯四甲酸二酐、对苯二胺为单体的聚合物主链中,通过共聚法获得聚酰胺酸(PAA)纺丝原液,并对该纺丝原液进行流变性能研究。结果表明:PAA纺丝原液是典型的假塑性流体,且在剪切速率大于100 s-1时,原液的切应力出现不稳定现象;原液的黏流活化能受剪切速率影响较大,当剪切速率大于10 s-1时,随着剪切速率增大黏流活化能迅速降低;原液的结构黏度指数随着分子质量的增大而增大,且随着PAA分子质量的增大,原液的临界凝胶点逐渐向低频方向偏移。 相似文献
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研究了聚间苯二甲酰间苯二胺溶液的固体质量分数、相对分子质量、温度对溶液流变性能的影响。结果表明:聚间苯二甲酰间苯二胺溶液的流变性能受溶液固体质量分数、相对分子质量、温度的影响明显,聚合物相对分子质量增大、溶液固体质量分数增加均使溶液表观黏度增大,温度升高使溶液表观黏度减小,溶液表观黏度随剪切速率的变化幅度较小。试验结果表明:适合干法纺丝的聚间苯二甲酰间苯二胺溶液的固体质量分数为31%35%,特性黏度为1.6 dL/g左右,纺丝时原液温度范围为5035%,特性黏度为1.6 dL/g左右,纺丝时原液温度范围为50120℃。 相似文献
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韩 《精细化工原料及中间体》2008,(8)
1熔融氨纶制造工艺技术
纤维级聚氨酯切片(采用一步法合成的纤维级热塑性聚氨酯粒子),经干燥、熔融、计量、纺丝、卷绕、上油、平衡等工序,即得到熔融纺丝氨纶产品。最初熔融纺丝氨纶产品在弹性回复率、耐热性等方面还不如干纺氨纶,但随着纤维级聚氨酯切片技术生产日益成熟及熔融纺丝技术的完善.熔融纺丝氨纶产品已可和干纺氨纶产品相媲美。 相似文献
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采用RT-2000毛细管流变仪,研究了海藻酸钠(SAL)/羧甲基壳聚糖(CMCS)纺丝溶液的流变性能。结果表明:SAL/CMCS纺丝溶液是切力变稀型流体,随着剪切速率(γ)的增加,纺丝溶液的表观粘度(η_a)下降;随着纺丝液中CMCS含量的增加,SAL/CMCS纺丝溶液的η_a和结构粘度指数(△η)下降,非牛顿指数(n)增大;随着纺丝液温度的升高,SAL/CMCS纺丝溶液的η_a和△η下降,n增大。纺丝过程中应控制SAL/CMCS纺丝溶液的温度为35℃,纺丝溶液中CMCS质量分数为15%较适宜。 相似文献
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Tao Jian Wei‐De Shyu Yue‐Tang Lin Kan‐Nan Chen Jen‐Taut Yeh 《Polymer Engineering and Science》2003,43(11):1765-1777
The concentrations and temperatures of ultrahigh‐molecular‐weight polyethylene (UHMWPE) gel solutions exhibited a significant influence on their rheological and spinning properties. The shear viscosities of UHMWPE solutions increased consistently with increasing concentrations at a constant temperature above 80°C. Tremendously high shear viscosities of UHMWPE gel solutions were found as the temperatures reached 120–140°C, at which their shear viscosity values approached the maximum. The spinnable solutions are those gel solutions with optimum shear viscosities and relatively good homogeneity in nature. Moreover, the gel solution concentrations and spinning temperatures exhibited a significant influence on the drawability and microstructure of the as‐spun fibers. At each spinning temperature, the achievable draw ratios obtained for as‐spun fibers prepared near the optimum concentration are significantly higher than those of as‐spun fibers prepared at other concentrations. The critical draw ratio of the as‐spun fiber prepared at the optimum concentration approached a maximum value, as the spinning temperature reached the optimum value of 150°C. Further investigations indicated that the best orientation of the precursors of shish‐kebab‐like entities, birefringence, crystallinity, thermal and tensile properties were always accompanied with the as‐spun fiber prepared at the optimum concentration and temperature. Similar to those found for the as‐spun fibers, the birefringence and tensile properties of the draw fibers prepared at the optimum condition were always higher than those of drawn fibers prepared at other conditions but stretched to the same draw ratio. Possible mechanisms accounting for these interesting phenomena are proposed. 相似文献
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The effects of solution composition and temperature on the viscoelasticity of concentrated polyacrylonitrile (PAN) solutions were studied using a variety of rheological measurements, such as steady‐state shearing, dynamic stress sweep and transient rheological tests. The first normal stress difference N1 and the shear stress τ were found to increase with decreasing temperature and increasing PAN concentration and water content in the solutions. The crossover point of N1 and τ, denoting the equal contribution of viscosity and elasticity to the viscoelasticity of the solutions, moved to lower shear rates at lower temperature, higher PAN concentration and higher water content. The values of the relaxation time (λ) were larger at 70 °C than at 40 °C. In addition, the changes of λ with PAN concentration and water content were different at the two temperatures, ascribed to the different states of the solutions. The PAN solutions were in the linear viscoelastic regime in the temperature range 40–70 °C when the shear stress was below 300 Pa. The creep compliance recovery rate decreased with increasing temperature, but increased with increasing PAN concentration and water content. Thixotropic tests showed that the thixotropy of the solutions was also affected by the solution composition and temperature. Gelation was found to influence the way the solution composition and temperature affected the viscoelastic properties of the PAN solutions. Copyright © 2011 Society of Chemical Industry 相似文献
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Fibers of poly(L -lactide) (PLLA) with a tensile strength up to 1.2 GPa and Young's modulus in the range of 12–15 GPA were obtained by a hot drawing of fibers spun from solution of PLLA in good solvents such as dichloromethane and trichloromethane. The tensile strength of fibers was strongly dependent on the molecular weight of PLLA and on polymer concentrations in the spinning solution. Changing of the polymer concentration in the spinning solution gives rise to formation of fibers with different shape and porosity. Fibers spun from 10–20% solutions at room temperature exhibit a regular structurization, due to the melt fracture. These fibers had knot strengths up to 0.6 GPa, whereas fibers with a smooth surface spun from more dilute solutions had weaker square knots up to 0.3 GPa. 相似文献
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聚酰胺酸纺丝溶液的流变性能研究 总被引:2,自引:0,他引:2
由均苯四酸二酐(PMDA)和4,4'-二氨基二苯醚(ODA)在N,N-二甲基乙酰胺(DMAc)中共聚合制得聚酰亚胺前驱体——聚酰胺酸的纺丝溶液,采用哈克流变仪研究了溶液的流变性能。结果表明:聚酰胺酸溶液属于切力变稀的非牛顿流体;溶液的表观黏度随溶液温度的升高而降低,随溶液浓度的升高或聚合物特性黏度的增大而增大。溶液温度的升高、浓度的降低或聚合物特性黏度的减小均使得聚酰胺酸溶液呈现切力变稀行为的临界剪切速率变大,使得溶液的非牛顿指数增大,同时使得溶液的结构黏度指数减小。溶液的黏流活化能随剪切速率的增加或随溶液浓度的增高而下降。 相似文献
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超高相对分子质量聚丙烯腈浓溶液的制备 总被引:1,自引:0,他引:1
通过高速搅拌剪切,使超高分子对质量聚丙烯腈(PAN)冻胶体系中缠结网络结构破坏,粘度降低,提高溶液浓度,以满足纺制高性能冻胶纺PAN纤维的需要,当高速搅拌条件为间隙0.28mm剪切速率420r/min时,可解除天生缠结,适宜的搅拌剪切条件是制行适合冻胶纺的超高相分子质量PAN溶液的关键。 相似文献