Hard elasticity of poly(vinylidene fluoride) fibers
Hard elasticity of poly(vinylidene fluoride) fibers
复制标题
聚偏二氟乙烯纤维的硬弹性
DOI：
10.1007/s10853-005-6528-x
复制
发表时间：
2005-02
影响因子：
4.5
通讯作者：
中科院分区：
文献类型：
--
作者：
硬弹性材料因其独特的晶体结构和力学性能，在科学技术领域引起了极大的兴趣。第一个硬弹性聚合物是1965年发现的聚甲醛纤维[1]，它表现出高的初始弹性模数和高的弹性回复率，例如从50%的伸长率弹性回复率高达92%。另一种弹性聚合物是长丝形式的聚丙烯(PP)，它出现在1966年的美国专利文献[2]中；它在拉伸25%后表现出82%的拉伸回复率。随后发现了更多的硬弹性聚合物，如聚(4-甲基-1-戊烯)(TPX)[3]、聚乙烯(PE)[4]。简而言之，这些纤维的正常和高度结晶的对应物的弹性特征似乎是由材料中特定的分子取向造成的。用X射线衍射法可以很容易地确定样品的取向。对PP硬弹纤维的进一步研究表明，当纤维被广泛拉伸时，该纤维显示出一种特殊性质的孔洞[5]。形成微空洞的机制是由于材料内部垂直于纤维轴的层状晶体结构。当纤维被拉伸时，晶片分离，形成大量相互连接的空洞。这就是为什么硬弹性聚合物可以通过熔融纺丝和拉伸(MS-S)工艺制备成中空纤维膜。采用MS-S法制备的I-PP[6]、PE[7]中空纤维膜已实现商业化，并在水处理中得到广泛应用。聚偏氟乙烯(PVDF)具有优异的耐化学性，是一种很好的膜材料。通过干/湿法纺丝工艺制备的PVDF中空纤维膜具有超滤性和微滤性。但采用MS-S法制备的中空纤维膜至今未见文献报道。在制备薄膜之前，首先要讨论PVDF纤维的硬弹性。用原位同步辐射X射线技术研究了PVDF在熔融纺丝早期的结构变化。检测到沿纤维轴排列的烤肉串晶体[8-11]，有缺陷的烤肉串结构最终转变为定义良好的片层结构[9]。舒尔茨和他的同事最近研究了PVDF纤维在变形时的结晶发展和力学行为。他们报告说，微晶通过沿纤维延伸的无定形链条连接在一起
Hard elastic materials are of great interest in science and technology for their unusual crystal structures and mechanical properties. The first hard elastic polymer is a polyoxymethylene fiber found in 1965 [1], which exhibits high initial elastic modulus and high elastic recoveries, eg elastic recoveries as high as 92% from 50% extensions. Another elastic polymer is polypropylene (PP) in filament form which appeared in the US patent literature in 1966 [2]; it exhibits a tensile recovery of 82% after an elongation of 25%. Subsequently more hard elastic polymers such as poly (4-methyl-1pentene)(TPX)[3], polyethylene (PE)[4] were found. Briefly, it appears that the elasticity characteristic of the normal and highly crystalline counterpart of these fibers results from a specific molecular orientation within the material. The orientation can be easily identified by X-ray diffraction techniques. Additional work on PP hard elastic fiber showed that the fiber exhibited a porosity of a peculiar nature when it was stretched widely [5]. The mechanism of forming microvoids is due to the stacked lamellar crystal structure normal to the fiber axis within the material. When the fiber is stretched, the crystal lamellae are separated with formation of large amount of interconnected voids. That is why hard elastic polymers can be prepared into hollow fiber membranes by melt-spinning and stretching (MS-S) process. Hollow fiber membranes such as i-PP [6], PE [7] made by MS-S process have been commercialized and widely applied in water treatments. Poly (vinylidene fluoride)(PVDF) is a good material for membranes for its excellent chemical resistance. Ultrafiltration and microfiltration PVDF hollow fiber membranes made through the dry/wet spinning process are commercially available. But the hollow fiber membrane produced by MS-S process has not been reported in the literature until now. Prior to dealing with the preparation of the membrane, hard elasticity of PVDF fibers should be discussed firstly.The structure development of PVDF in the early stages of melt spinning has been studied using in-situ synchrotron X-ray techniques. Shish-kebab crystals aligned along the fiber axis were detected [8–11], the defective shish-kebab structure eventually transforms into a well-defined lamellar structure [9]. Schultz and co-workers [12] recently studied the crystal development and mechanical behavior of PVDF fibers under deformation. They reported that crystallites linked by extended amorphous chains along the fiber
登录
查看更多内容
DOI：
10.1080/00222347008217135
发表时间：
1970-12
期刊：
Journal of Macromolecular Science, Part B
影响因子：
--
作者：
G. R. Quynn;H. Brody;E. S. Sobering;K. K. Park-K.;L. Foley;D. H. Noethe;W. Whitney;R. Pritchart;A. M. Seiminki;D. Hutchison;L. H. Wagner;J. Sumit;K. Sakaku;R. Karneluisson
通讯作者：
G. R. Quynn;H. Brody;E. S. Sobering;K. K. Park-K.;L. Foley;D. H. Noethe;W. Whitney;R. Pritchart;A. M. Seiminki;D. Hutchison;L. H. Wagner;J. Sumit;K. Sakaku;R. Karneluisson
影响因子：
5.5
作者：
Jing Wu;J. Schultz;F. Yeh;B. Hsiao;B. Chu
通讯作者：
Jing Wu;J. Schultz;F. Yeh;B. Hsiao;B. Chu
影响因子：
4.6
作者：
Joshua M. Samon;J. Schultz;B. Hsiao
通讯作者：
Joshua M. Samon;J. Schultz;B. Hsiao
影响因子：
2.4
作者：
H. Noether;W. Whitney
通讯作者：
H. Noether;W. Whitney
影响因子：
5.5
作者：
Joshua M. Samon;J. Schultz;B. Hsiao;S. Seifert;N. Stribeck;I. Gurke;Collinscheng Saw
通讯作者：
Joshua M. Samon;J. Schultz;B. Hsiao;S. Seifert;N. Stribeck;I. Gurke;Collinscheng Saw