Physical structure of elastic “hard” fibers
Physical structure of elastic “hard” fibers
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DOI：
10.1080/00222347008217135
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发表时间：
1970-12
期刊：
影响因子：
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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
中科院分区：
文献类型：
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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
已经发现[11]，聚丙烯、聚-3-甲基丁烯-1和它的一些1-烯烃共聚物以及缩醛共聚物Celcon在从熔体结晶期间的高应力条件下可以形成高度结晶的宏观纤维，其显示出异常高的从拉伸的长度恢复度（例如，用聚丙烯纤维从100%拉伸恢复97%）。这些材料中的一些已经在专利[la-f]中描述，但是它们的物理结构尚未阐明。早在1965年，这个实验室就对这类不寻常的材料的物理性质进行了全面的研究。在以前已知的所有高聚物固体中，只有低结晶度的弹性体具有高弹性，即从高伸长迅速且几乎完全回缩的能力。我们现在已经发现了一类新的高结晶度的弹性聚合物固体，其由于特定的形态而经历大的弹性变形。在我们的实验室里，这些材料被称为弹性“硬”结构。我们还发现[lc]，弹性硬纤维在拉伸时表观密度发生显著的、主要是可逆的降低，例如，某些聚丙烯纤维样品在110%拉伸时的未拉伸密度减半。高压压汞孔隙率测定法证实了相对密度的微观测量结果，并表明在拉伸时纤维内形成了可接近的亚微观空隙;孔隙率测定法和其他测量结果表明，大部分空隙空间容易接近气体和液体。它由尺寸单位组成，线性尺寸从几千埃向下，范围主要取决于延伸量。Brunauer-Emmet-Tellen气体吸附测量同样表明可及表面积的拉伸非常大的增加。弹性纤维和薄膜表面的电子显微镜复制品显示出紧密堆积的层状结构，其法线主要平行于纤维或薄膜挤出方向。在平行于挤出方向拉伸弹性材料时，薄片倾斜并张开，产生间隙或裂缝，
It has been found [11 that polypropylene, poly-3-methylbutene-1 and some of its 1-olefin copolymers, and the acetal copolymer Celcon, under conditions of high stress during crystallization from the melt, can be formed into highly crystalline, macroscopic fibers which display an unusually high degree of length recovery from extension (for example, 97% recovery from 100% extension with polypropylene fiber). Some of these materials have been described in patents [la-f], but their physical structure has not been clarified. Early in 1965 this laboratory undertook a comprehensive investigation of the physical properties of this unusual class of materials. Of all high polymer solids previously known, only elastomers of low crystallinity exhibit high elasticity, ie, the ability to retract rapidly and nearly completely from high extensions. We have now found a new class of elastic polymeric solids of high crystallinity that undergo large elastic deformations due to a specific morphology. In our laboratory these materials are referred to as elastic “hard” structures. We have also found [lc] that elastic hard fibers undergo on stretching a marked, mainly reversible, reduction in apparent density, eg, a halving of the unstretched density at 110% extension with certain polypropylene fiber specimens. High-pressure mercury porosimetry confirms microscopic measurements of relative den-sity and indicate that accessible, submicroscopic voids are formed within the fiber on stretching; porosimetry and other measurements indicate that the majority of this void space is readily accessible to gases and liquids. It consists of size units ranging in linear dimensions from several thousand Angstroms downward, the range depending mainly on the amount of extension. Brunauer-Emmet-Tellen gas adsorption measurements likewise indicate a very large increase on stretching of accessible surface area. Electron-microscopic replicas of the surfaces of elastic fibers and films show close-packed lamellae with their normals predominately parallel to the fiber or film extrusion direction. On stretching the elastic materials parallel to the extrusion direction the lamellae tilt and splay apart, creating gaps or crevasses which are believed