THE DENSITY AND REFRACTIVITY OF CELLULOSE FIBRES IN RELATION TO THEIR STRUCTURE
THE DENSITY AND REFRACTIVITY OF CELLULOSE FIBRES IN RELATION TO THEIR STRUCTURE
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纤维素纤维的密度和折射率与其结构的关系
DOI：
10.1080/19447014708662932
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发表时间：
1947
期刊：
影响因子：
--
通讯作者：
P. H. Hermans
中科院分区：
文献类型：
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作者：
P. H. Hermans
这堂课的主题是“纤维素纤维的密度和吸水性”，这是经常讨论的话题。它已经被研究过了，在现行的教科书中有很多信息。然而，当我们在战争期间在我们新建的实验室里开始对与人造丝有关的某些物理问题进行基础研究时，我们很快就感到现有的信息对我们的目的来说是非常不充分的，并决定重新调查此事，以便为其他更普遍的工作提供可靠的基础。本文的目的是对纤维素纤维的密度和光学性质的研究工作以及由此产生的理论前景作一个简要的概述。这种观点在几个方面与现在的文本和书籍中的观点不同。我首先考虑纤维密度。在简要回顾了处理这个问题的通常方法之后，我将解释我们自己的调查所引导的想法。然后，我将阐述我们如何通过平行测量纤维的折射率来检验我们的结论。在纤维工作中，密度和结晶活性之间的简单关系没有引起注意，而这在其他领域如有机化学中是众所周知的。此外，我还希望向你们展示吸湿是如何影响密度和折射率的，以及这些现象如何与我们目前的纤维结构相联系。密度的测定总是归结为体积的测定.将材料浸没在液体或气体中，并测量排出的液体或气体的体积。现在我相信突出的一点是，纤维素纤维迄今为止一直被认为是或多或少的多孔体。我不需要向你解释这个想法的原因。每个熟悉棉花和其他天然纤维的人都知道这些纤维有内腔。此外，Clegg和Harland的工作表明，当用显微镜精确测量时，纤维壁本身的体积导致密度值i。而纤维素的预期密度和在惰性有机溶剂例如苯中实际发现的密度为约1 - 5。这表明，在纤维壁本身中，有许多微孔系统，可能是生物起源的，这些液体可以渗透。现在，在考虑纤维密度时，在密度测定中使用的介质的渗透能力起了主要作用。人们早就知道，像木炭和陶瓷材料这样的微孔体的密度取决于所使用的介质。这被解释为由于一些介质能够比其他介质更彻底地渗透到孔隙中。在测量这种微孔体的密度时，只有当使用能够完全填充孔的介质时，才能发现固体本身的实际密度。如果孔隙的某些部分仍然不能进入介质，那么密度值当然会太低。Cude和Hulett发现，当在各种有机液体中测量时，木炭产生不同的数字，并且这些数字都低于来自X射线照片的结晶石墨的密度。另一方面，当在空气中测量时，发现的数字远高于石墨的密度，这可以表明这是由于吸附，或 * 来自AKU和附属公司Utrecht（荷兰）纤维素研究实验室的第44号通信。1946年5月28日，在曼彻斯特技术学院纺织化学系和学院研究讨论会的主持下，由JM普雷斯顿先生主持的一次演讲。
The subject of this lecture," the density and refractivity of cellulose fibres," has often been discussed. It has been studied, and there^ is much information in the current textbooks. Yet, in starting a programme of fundamental research on certain physical problems concerned with rayon, in our newlyerected laboratory during the war, we soon felt that the available information was quite insufi&cient for our purpose and decided to reinvestigate the matter, in order to get a reliable basis for other work of a more general kind. The object i6 to give a brief sur\'ey of this work on the density and the optics of cellulose fibres and of the theoretical outlook which has arisen therefrom. This outlook differs in several respects from what is in the text, books now. I shall first consider fibre density. After briefly recalling the usual way of treating this subject, I shall explain the ideas to w^ hich we have been led by our own investigations. I shall then set forth how we checked our conclusions by parallel measurements of the refractive power of fibres. In fibre work no attention has been paid to the simple relationship between density and refractivity, which is so well known in other fields such as organic chemistr}'. Further, I hope to show you how density and refraction are influenced by moisture absorption and how these phenomena may be connected with our present picture of fibre structure. Density determinations always resolve themselves into the determination of volumes. The material is submerged in a liquid or in a gas and the volume of the liquid or of the gas displaced is measured. Now I believe the outstanding point is that cellulose fibres have hitherto been regarded as being more or less porous bodies. I need not explain to you the reason for this idea. Everyone familiar with cotton and other natural fibres knows that these fibres have a lumen. Moreover, it was sho\\Ti by the work of Clegg and Harland that the volume of the fibre wall itself when accurately measured by the microscoj^ e leads to a density value of i-. i5 whereas the density to be expected for cellulose and actually found in indifferent organic solvents, for instance in benzene, is about 1-5. This shows that in the fibre wall itself there mufet occur a system of tiny pores, probably of biological origin, which these liqtiids can penetrate.Now it is the penetrating power of the medium used in the density determinations which has played a major part in considerations of fibre density. It has long been known that the densities of microporous bodies like charcoal and ceramic materials depend on the medium used. This was explained as due to some media being capable of penetrating more thoroughly into the pores than others. In measuring the densit}--of such a microporous bod}"-the actual density of the solid proper will be found only when using a medium which is capable of completely filling the pores. If some portion of the pores remains inaccessible to the medium, the density figure will, of course, be too low. Cude and Hulett found that charcoal yields different figures w^ hen measured in various organic liquids and these figures were all lower than the density of crystalline graphite as derived from X-ray photographs. On the other hand, when measured in air as a medium, figures much higher than the density of graphite were found. It could be shown that this was due to an adsorption, or* Communication No. 44 from the Laboratory for Cellulose Research of the AKU and afaiiated companies, Utrecht (Netherlands). t A lecture delivered at the College of Technology, Manchester, under the auspices of the Department of Textile Chemistry and the Research Colloquium of the College, on 28th May, 1946, Mr. JM Preston in the Chair.