WETTING BEHAVIORS OF ASSEMBLIES OF VARIOUS FIBERS

Abstract

Continued from the proceeding studies, the authors describe the steeping method for the comparative measurements of wetting of the fiber assemblies by distilled water, constructing the assemblies in different stuructures and from various kinds of fibers. An improved hydrometer method was used in which the strain meter and the pen oscillograph were used for the measurement of weight of the sampless. The types of sample fibers and the method of scouring are described in the previous articles. Five different degrees of porosities (degree of opening) of fiber assemblies were obtained by stuffing the specified quantity of each fiber sample into the cylindrical containers which were made from stainless steel wire netting and in five degrees of capacities.The sample fiber assemblies was steeped in distilled water and then hung on the arm of straingauge. The relationship between the weight of sample (Ws) and the elapsed time (Ts) was recorded on the oscillograph chart. Thus, as in the hydrometer method, the relationship between the apparent density of sample (Dap) and the elapsed time (Ts) were obtained on various types of fibers and on different degrees of porosities. Moreover, the dependency of the retained air index (Va/Vc) of the assemblies on the elapsed time could also be obtained from these data and this could be used as an index in an analysis of the wetting behavior of the samples.The great varieties were found on the values of Dap and Va/Vc for each elapsed time with the types of fiber in the case of the same degree of porosity: the assemblies of acrylic, absorbent cotton, rayon and Vinylon were penetrated very rapidly, that of acetate and nylon ranked next, and polyester the last. Finally, penetration of polypropylene and scoured wool by water was found to be exceedingly small. The characteristic wetting behavior of each fiber assembly could be found by careful examination of the data. The assembly of acrylic was penetrated very rapidly and almost perfectly at all ranges of porosity examined. The property depends, however, on the type of components which has been used in the copolymerization, in small quantity, with polyacrylonitorile. The wetting behavior of assemblies of various kinds of acrylics will be dealt with in a next article.