Yarn appearance

Generally, the processing and yarn qualities of the unwashed cotton were better than those of the washed cottons (Table III). However, from a practical standpoint the differences were not great. The differences of greatest practical significance concerned factors that affect yarn appearance, and these factors were clearly superior for the unwashed cotton. 

This cotton was carded at 13.6 kg/hr and processed into 1A.8 mg/m yarn of 37.2 twist factor at 10000 rpm spindle speed. Ends down per thousand spindle hours was AO as compared to 56 for the same cotton washed on the rayon line. Yarn appearance characteristics were also slightly better for the wool scoured cotton. 

C. In each a core of yarns appears to be wrapped with featherlike structures, which are then bound to the core by a fine yam with no twist (Figure 12). System A yams measure 4.20 mm the featherlike structures exhibit the characteristic shapes of downy barbules found on feathers, as indicated earlier. Scholtz (12) considers the complex yarns to be re-plied yams because the core consists of plied yams, and a wrapping yarn encircles the core unit. Modem textile specialists would classify yams... 

Several layers of fabric-type formations were observed in each location. It is impossible to know whether these pseudomorphs consisted of a single fabric with surface decoration or several layers of the same fabric or even different fabrics (18). The upper or top layers of the fabric formations generally contained large black yarns parallel to each other (system A). Rather consistently, the green, single-fiber yarn and the paired-fiber yarns appeared in both systems A and B or in one (system B) that interlaced with black yarns in the other (system A). Green, paired-fiber yarns also appeared occasionally along the surface in a nonrectilinear situation. 

Further aspects of yarn appearance are the yarn titer and the number of filaments there may be thin or thick yarn bundles. This will obviously depend on the application. 

A technological characteristic of OE-rotor spinning is the presence of wrapper fibers (Fig. 3.19). When fibers are attached to the end of the twisted yarn in the rotor groove (a), they wind around the yarn end with one fiber end in the direction of yarn twist and with the other fiber end opposite to the direction of yarn twist (b-d). Such wrapper fibers, also called blurbs, are characteristic for OE-rotor yams. The resulting yarn appearance is attractive in some products, for example, blue Jeans. In other products, these wrapper fibers are unwanted. In yarns for cut-pile carpets, wrapper fibers are disadvantageous, as they prevent the pile from opening uniformly. 

The assessment of the rate of degradation follows a classic Arrhenius procedure. Yarns or specimens of film are exposed to water and steam at temperatures typically between 70 °C and 130 °C, followed by tensile testing and molecular weight determination, and the results are extrapolated to service temperatures [32]. There are however a number of uncertainties. Firstly, will steam above 100 °C and water below 100 °C have the same effect There appears to be a change in gradient at 90 °C extrapolation using all the... 

In any case, the appearance of fluorescence is accompanied by significantly reduced spinnability. Figure 13.19 shows an impressive example of the fluorescence of three PET samples with different spinnability. The term excellent is here applied to the processability of polymer A, which is by far superior to that of the other two samples. Polymer A could be processed without almost any yarn breaks in POY spinning (167 dtexf 32,1 winding speed 3300m/min), polymer B showed an acceptable performance, whereas polymer C gave many yam breaks and therefore a bad performance. The break rate is proportional to the... 

Acrylic fibers generally have good hand, as its called in the business (they re soft). They resist creasing, and they are quick to dry. Acrylics have replaced wool in many applications, such as blankets and sweaters. Because of their unique bulking characteristics, they take on the appearance of wool yarn. 

While some of the Mississippian textiles are of similar structure to the Middle Woodland textiles, others are very complex materials and are lace-like in appearance. Many of the materials from Etowah are preserved by mineralization, and display green-colored deposits on their surfaces. Bast fiber, rabbit hair, and feathers have been identified (2, 11). The textiles from these two sites selected for analysis are representative of the complexity of structure and fineness of yarns seen in the materials they provide evidence of the sophisticated technology of prehistoric people in all phases of fiber collection, processing, yarn spinning, fabric manufacture and, when present, coloration. 

An initial run on a 76 ug sample of Nylon 6, 6 yarn (seen in fig. 14) shows a processing effect at about 210°C, the same temperature at which this material displayed a break in the TMA extension curve. After shock cooling, the processing mark has been erased and the cold recrystallization peak appears--an indication that the glass transition is about 25°C lower. Figure 15 shows the effect of program-cooling and the characteristic nylon double peak in the subsequent melt (9). 

The final yarn is golden yellow, and because this color appears to be an intrinsic property of the polymer, it may have some limitation as far as the civilian market is concerned. This material originally suffered from... 

The Etowah fabric bundle (No. 840) contains fine yarns made of bundles of vegetable fibers typical of bast fibers. The core yams of Etowah Mound C (EMC) No. 1145 also are bast, and they are wrapped with feathers. Figure 10 is an electron micrograph of the nodes on the barbules of these feathers. The copper plate EMC No. 1156 contains a twisted yarn of undetermined fiber composition the fibers are smooth, untwisted, and long. Perhaps they are hair, but no scale structure was apparent on their surfaces. In the same area of the plate, some loose fibrous material adjacent to the yam proved to be feather. In a second area of the plate, some fibrous material of undetermined type similar in appearance to that in the first area is present. 

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