共查询到19条相似文献,搜索用时 140 毫秒
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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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为了研究PAN纤维干喷湿纺中凝固浴牵伸的作用机理。采用DMso水溶液作为凝固浴,利用纤维强伸度仪、分析天平、X射线衍射仪、电子探针等手段,研究了干喷湿纺中凝固牵伸对PAN初生纤维及最终原丝结构及性能的影响。结果表明,干喷瀑纺中,在凝固浴浓度(65%)、温度(20℃)、空气层厚度(2mm)等条件下,随凝固浴牵伸的增加,初生纤维及PAN原丝的孔隙率逐步降低,结晶度逐渐增大,初生纤维表现出较高的断裂强度,纵表面更加光洁,横截面更加致密;适当调整凝固浴牵伸,得到了纤度1.01dtex,强度7.52cN,dtcx的聚丙烯腈原丝。 相似文献
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介绍了一种用于PAN原丝工业化生产装置的智能控制系统及其工作原理。通过在线监测凝固浴浓度(DMSO溶液),自动调节补水量,以维持凝固浴浓度的稳定。该装置的使用可提高工艺参数的控制精度,在腈纶湿法纺丝及PAN基碳纤维原丝工业化生产中具有广阔的应用前景。 相似文献
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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。 相似文献
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Quan Gao Min Jing Meiling Chen Shengyao Zhao Yuxia Wang Jianjie Qin Meijie Yu Chengguo Wang 《应用聚合物科学杂志》2020,137(44):49380
The coagulation process was vital for the microfibril evolution and mechanical properties of polyacrylonitrile (PAN) fibers. The PAN nascent fibers and precursor fibers were prepared by controlling drawing ratio of coagulation bath at low temperature during the dry-jet wet spinning process. The microfibril morphological changes induced by force fields in coagulation bath were investigated by scanning electron microscopy and high-resolution transmission electron microscopy. During the coagulation process, the spinning solution evolved into an interconnected network composed of random microfibrils and tie joints as a building block of the network. At low drawing ratio, the random interconnected network existed in nascent fibers. Increasing drawing ratio, the fiber filaments underwent shrinkage and the network was transformed into the transverse lamellae. Furthermore, the lamellar thickness also decreased. After the treatment of post-spinning, similar transverse lamellae were formed in all of precursor fibers, and random microfibrillar network was stretched and oriented to develop into the aligned microfibrils in precursor fibers. The transverse fold-chain crystal layers were densely stacked in the microfibrils. Increasing drawing ratio, the lamellae and microfibrils in precursor fibers were packed more densely and orderly. Consequently, the order and homogeneity of microfibrils in nascent fibers and precursor fibers were improved by increasing drawing ratio, which were benefit to increase fiber tensile strength and modulus. 相似文献
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DMSO湿法PAN纤维截面形状形成条件的研究 总被引:3,自引:0,他引:3
对DMSO(二甲基亚砜)湿法制备PAN(聚丙烯腈)纤维的截面形状的形成因素进行了研究。随着凝固浴浓度的增大和温度的升高,纤维截面形状由椭圆形或肾形逐渐变为圆形。当凝固浴浓度在一定范围(55%-70%)时,不同凝固浴浓度对应一个凝固浴温度下限值,在该下限温度以上都可得到圆形截面纤维,且凝固浴浓度越低,此下限温度越高。纤维离开凝固浴后,截面形状基本形成并固定,水洗、拉伸、喷丝速度和干燥对纤维截面形状的形成影响都很小。 相似文献
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Md Abdullah Al Faruque Rechana Remadevi Joselito M. Razal Maryam Naebe 《应用聚合物科学杂志》2020,137(41):49264
The study examined the effect of different wet spinning parameters (e.g., total solid content, coagulation bath concentration, drawing, and stretching) on the morphology and mechanical properties of the wet spun alpaca/polyacrylonitrile (PAN) composite fibers. The alpaca/PAN composite fibers were wet spun using 10, 20, and 30% of alpaca particles along with the PAN polymer. The shear-thinning or non-Newtonian flow behavior was observed among the dope solutions with different solid content. The cross-sectional fiber morphology showed the bean-shaped characteristic for the control PAN fibers, whereas the alpaca/PAN composite fibers exhibited almost circular shape. “Cavity healing” was observed, where noticeable voids and porous areas were demolished in the cross section of the composite fibers, by changing the total solid content and coagulation bath concentration. Although the control PAN fibers exhibited the highest tenacity with lower fiber diameter, the alpaca/PAN composite fibers showed a gradual deterioration in tenacity while adding alpaca particles into the PAN polymeric matrix. Nevertheless, due to the increment in the total solid content, higher draw ratio, and stretching of the fibers, the tenacity, molecular orientation, and the crystallinity of the composite fibers were increased. 相似文献
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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 fiber spinning methods determine the formation of the physical structures of polyacrylonitrile (PAN) fibers which further affect stabilization reactions and the mechanical performances of the resultant carbon fibers. In this study, PAN fibers were prepared by both dry-jet gel spinning (g-PAN) and dry-jet wet spinning (w-PAN), and their stabilization behaviors were compared. While the stabilized w-PAN fibers show sheath-core structures, the stabilized g-PAN fibers exhibit relatively uniform stabilized structures along the radial direction. Additionally, the stabilization reactions of g-PAN fibers occur faster than that of w-PAN fibers, and the cyclization, oxidation, and crosslinking reaction activation energies of g-PAN fibers are lower than that of w-PAN fibers, respectively. Moreover, the carbon yield of g-PAN is higher than that of w-PAN fibers. We believe that above changes are possibly ascribed to the formation of different PAN sheath structures and oriented chain structures during dry-jet wet spinning and dry-jet gel spinning. It is concluded that gel spinning could significantly reduce the sheath-core difference of PAN fibers and the stabilized fibers as compared with wet spinning, which leads to a faster stabilization and more uniform stabilized structures. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 137, 48671. 相似文献
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凝胶化理论初探及PAN原丝的凝胶法纺丝 总被引:2,自引:1,他引:1
提出了一种聚丙烯腈(PAN)原丝的新型纺丝方法—凝胶法纺丝技术。根据凝胶化理论,从溶液浓度、体系的凝胶化温度和非溶剂水的影响3个方面对PAN原丝凝胶法纺丝进行深入的研究,并与干湿法纺丝进行比较,得出重要结论:凝胶法纺丝所得的PAN原丝皮芯结构差更小,平均孔洞半径更小,结构更致密,孔洞相对体积分数大幅度下降,力学性能更佳。 相似文献