Moisture in Textiles 



By ALBERT C. WALKER 



Evidence is presented that for a cotton hair structure of the 

 specific type described, calculations are in such close agreement 

 with many experimental data as to suggest the following tentative 

 conclusions: 



1. The moisture content necessary to form a monomolecular 

 layer on all internal surface of the cotton hair appears to be 

 slightly more than 1 per cent of the hair weight. 



2. Less than half the internal surface, that termed fibril surface, 

 appears to be involved in moisture adsorption which causes ap- 

 preciable transverse swelling of the cotton hair. Upon this surface 

 multimolecular chains of water seem to condense, the length of 

 such chains increasing progressively up to saturation with corre- 

 sponding increases in hair diameter throughout the whole of this 

 range, each hydroxyl group in the cellulose surface being the base 

 of a water chain, with separations between these chains along 

 the surface corresponding to the arrangement of the hydroxyl 

 groups on the cellulose surface. 



3. Moisture adsorbed on surfaces within the cellulose aggregates 

 composing the fibrils does not appear to be involved in transverse 

 swelling, but may be responsible for the slight longitudinal swelling 

 exhibited by cotton. The capacity of the cotton hair for this tyi:)e 

 of adsorption suggests that its locus is the ends of crystallites and 

 therefore within the body of the fibrils. To account for the slight 

 swelling, it is assumed that only a monomolecular layer can be ad- 

 sorbed on these surfaces. 



4. A theory is proposed to ex])lain the dependence of the elec- 

 trical properties of textiles upon their moisture adsorbing proper- 

 ties, and upon the surface distribution of moisture within the 

 submicroscopic structure. 



1. Introduction 



A STUDY of the electrical properties of textiles and their de- 

 pendence on atmospheric conditions and naturally-occurring 

 impurities in the material has resulted in important economies and 

 improvements in the use of textile insulation in the telephone industry. 

 Recently, calculations have been made as to the moisture content and 

 swelling of cotton at various equilibrium conditions, based on assump- 

 tions, first as to the structure of the cotton hair,* then as to the 



* In keeping with recognized terminology, the individual cotton fiber is called a 

 hair, suggestive of its morphological origin. 



228 



