共查询到18条相似文献,搜索用时 62 毫秒
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通过湿法纺丝工艺制备聚丙烯腈(PAN)初生纤维,借助于X射线衍射仪、声速仪、扫描电子显微镜、小角X光散射仪等,研究了凝固浴温度、凝固浴浓度、喷丝头拉伸等凝固条件对初生纤维晶态结构、取向结构、形态结构的影响。结果表明:PAN纤维的凝聚态结构和形态结构在初生纤维形成时已基本形成;PAN初生纤维的结晶度达40%以上,其结晶度和结晶尺寸受凝固浴温度和浓度的影响;PAN初生纤维和原丝的晶区取向和全取向随着喷丝头拉伸的增大而增大;PAN初生纤维具有沿纤维轴向高度取向的沟槽,通过改变成形条件,可以获得沟槽浅且规整性完美的纤维表面;提高凝固浴浓度,可以形成结构均质、致密的PAN初生纤维,避免皮芯结构及芯部出现较多孔洞。 相似文献
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本文主要把腈纶NaSCN湿法与杜邦干法纺丝在工艺过程、成形机理、工艺参数及纤维结构等方面进行比较,进而总结了两种纺丝方法的不同特点。 相似文献
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《合成纤维工业》2017,(5):43-46
在聚丙烯腈(PAN)原丝湿法纺丝生产过程中,以二甲基亚砜/水(DMSO/H_2O)为凝固体系,在DMSO质量分数为72%,温度为52℃的凝固浴中通过流量计定量加入氨,以凝固浴溶液的pH值衡量氨化量的大小,研究了不同pH值对PAN原丝结构、性能及可纺性的影响。结果表明:在凝固浴溶液的pH值为8.6~10.0时,PAN原丝径向形态由腰形变成腰圆形,最后变成圆形;随着凝固浴溶液pH值的升高,PAN原丝的结晶度先升高后下降,膨润度则先降低后升高,直径不均率下降,强力不均率先下降后升高;凝固浴溶液pH值为9.5时,PAN原丝的结晶度最高,膨润度最小,直径不均率和强力不均率最低,可纺性最好,最终PAN基碳纤维的强度最高为3.83 GPa。 相似文献
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采用在线张力仪、光学显微镜、声速仪、紫外光谱、比表面积测定仪等手段研究了干湿法聚丙烯腈(PAN)纤维制备过程中纺丝速度对纤维形貌和结构的影响。结果表明随纺丝速度的提高凝固丝条上的张力线性增大,初生纤维的全取向程度也随之增大;凝固效果没有受到速度变化的影响,没有大的孔洞缺陷生成,纤维的力学性能没有受到影响。 相似文献
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凝固条件对PAN初生纤维微孔结构形态的影响 总被引:6,自引:5,他引:1
采用一维多取向小角X射线散射研究了聚丙烯腈细流在凝固过程中,凝固浴温度、浓度以及喷丝头拉伸比对初生纤维中微孔结构形态的影响。结果表明,凝固温度由30%提高到60℃时,微孔沿纤维轴取向增强,微孔尺寸减小,但微孔数量增加;凝固浴质量分数由67.5%升高到76.0%,微孔数量减少,但微孔尺寸变大,微孔沿纤维轴取向减弱;喷丝头拉伸比为-36.7%-10%时,微孔尺寸和取向角都增大。在凝固浴温度为52-55℃,凝固浴质量分数为70%,选择负拉伸能得到性能优异的初生纤维。 相似文献
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干湿纺中聚丙烯腈原丝凝固成形的探讨 总被引:1,自引:0,他引:1
介绍了聚丙烯腈(PAN)碳纤维原丝在以温度为主导的热致变和浓度为主导的双扩散致变下的成形过程,分析了凝固pH及牵伸率等对凝固成形的影响,并对干湿纺下淬火成膜,膜内液滴变化、细颈区拉伸等作出新的解释,从而对干湿纺下凝固成形的机理有一定的宏观把握,为纺出高品质的PAN原丝奠定理论基础. 相似文献
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干-喷湿纺聚丙烯腈纤维拉伸工艺研究 总被引:1,自引:0,他引:1
研究了干 -喷湿纺聚丙烯腈 (PAN)初生纤维的喷丝头拉伸比和三级拉伸 (空气拉伸、DMF浴拉伸、热水和沸水拉伸、干热拉伸 )工艺中各拉伸比对纤维性能的影响。结果表明 :提高喷丝头拉伸比可明显地降低初生纤维的线密度 ,提高强度 ;三级拉伸工艺中各拉伸比的提高均有利于PAN纤维线密度的减小及其强度、声速取向度和抗张模量的提高 ;合理调配三级拉伸中各拉伸比可制得强度超过 7.0cN/dtex的PAN纤维 相似文献
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The effect of coagulation bath condition on the structure and property of the nascent fibers and polyacrylonitrile fibers during wet‐spinning is studied. The best coagulation condition to produce polyacrylonitrile fibers has been found by examination of EA, XRD, SEM, and so on. The results indicated that when the coagulation bath was DMSO/H2O system, the temperature was 60°C, the concentration was 65%, the minus stretch ratio was ?10%, fine crystallites and high degree of crystallization in the nascent fibers and polyacrylonitrile fibers could be achieved, and less solvents remained in the nascent fibers with circular cross section morphology. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007 相似文献
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浅析了影响腈纶生产质量稳定的控制因素,主要包括原液质量、纤维成形工艺等。正常生产中,控制聚丙烯腈(PAN)浆化液质量分数为26%,PAN溶液质量分数为13.5%,凝固浴硫氰酸钠质量分数为8%~12%,以及严格控制其他工艺条件,有利于生产稳定。 相似文献
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对硫氢酸钠湿法二步法腈纶进行增白,探讨了主要增白工艺条件对增白效果的影响。认为低线密度纤维增白效果较好。另外,生产中增白母液喷淋量控制在15~20m~3/h,浓度0.8%~1.5%,增白前纤维黄度控制小于8,增白剂用量小于0.5%,增白时间5s,所得纤维的增白效果明显。 相似文献
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Mathematical simulation of wet spinning coagulation process: Dynamic modeling and numerical results
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Nan Xu Yongsheng Ding William E. Schiesser Mayuresh V. Kothare 《American Institute of Chemical Engineers》2016,62(9):3432-3440
A dynamic model of polymer wet spinning coagulation process is proposed in this article. The model is based on the double diffusion phenomenon, phase separation process, continuity balance, and momentum balance of the entire coagulation process. The uniqueness of the model lies in its dynamic feature. The model can simulate the system's dynamic response to variations in system inputs/parameters. Steady‐state system solutions can also be produced as the long‐time solutions of the dynamic model; a settling time can be observed at the same time. This paper employs a computationally efficient method of lines numerical algorithm for solving the dynamic model. A simulation experiment on a selected non‐solvent‐solvent‐polymer ternary system is carried out to verify the model as well as the numerical method. The dynamic simulation results are analyzed and discussed. At the end of the article, h‐refinement and p‐refinement are used to confirm the spatial convergence of the numerical solutions. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3432–3440, 2016 相似文献
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The jet stretch of wet‐spun PAN fiber and its effects on the cross‐section shape and properties of fibers were investigated for the PAN‐DMSO‐H2O system. Evidently, the spinning parameters, such as dope temperature, bath concentration, and bath temperature, influenced the jet stretch. Also, under uniform conditions, the postdrawing ratio changed as well as that of jet stretch. When coagulation temperature was 35°C simultaneously with bath concentration of 70%, jet stretch impacted obviously the cross‐section shapes of PAN fiber, but had little effect when the temperature was below 10°C or above 70°C. As the jet stretch ratio increased, the crystallinity, crystal size, sonic orientation, and mechanical properties of the as‐spun fiber changed rapidly to a major value for jet stretch ratio of 0.9 where the cross section of as‐spun fiber was circular. With further increasing of jet stretch ratio, the properties changed slightly but the fiber shape was not circular. The results indicated that appropriate jet stretch, under milder formation conditions in wet‐spinning, could result in the higher postdrawing ratio and circular profile of PAN fiber, which were helpful to produce round PAN precursor with minor titer and perfect properties for carbon fiber. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 相似文献
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湿法纺丝制备水溶性PVA纤维工艺探讨 总被引:2,自引:1,他引:1
阐述了制备水溶性聚乙烯醇(PVA)纤维原料的选择,纺丝原液的制备,纺丝及后处理工艺条件。 利用聚合度不大于1 700、醇解度不大于99%的各种牌号PVA,可用湿法纺丝制得溶解温度在60℃以上的水 溶性PVA纤维。 相似文献