The crimp in all-cotton, nylon, and polyester/spandex core stretch fabrics was ex amined by physical tests and by photographic enlargements of yarns and fibers removed from the fabrics. Measurements of total crimp and crimp due to yarn crossover indicate that yarn crossover crimp, external yarn crimp, has a major influence on the stretch and recovery properties of the comfort stretch fabrics having less than 30% stretch. Hysteresis curves show that faisetwisted nylon is significantly changed by weaving and subsequent finishing treatments. Nylon yarns raveled from stretch fabrics and filaments removed from the yarn show no evidence of residual effects of fatsetwisting if the fabric has less than 30% easy strech. The limited data obtained in this study indicate that interfiber friction may play a significant part in the stretch and recovery properties of all-cotton stretch fabrics. These data also suggest that fabric design and processing procedures that promote crossover yarn crimp are the areas most likely to improve the stretch and recovery properties of a comfort stretch cotton fabric.

A number of experimental yarns were spun from partially acetylatecl (PA) cotton stock to determine some of the factors that improve its mechanical processing and yarn properties. These studies indicated that blending PA cotton stock with raw cotton was a better method of preparation for mechanical processing than the use of an antistatic treatment on the PA stock. Blending resulted in better mechanical processing and improved yarn properties at a lower cost. Blending high acetyl PA cotton with 40% raw cotton was considered to be the best method of preparation. PA stock prepared from a rain-grown cotton exhibited better mechanical processing characteristics than stock prepared from a longer-staple irrigated cotton. However, yarns spun from the latter type of PA cotton had better properties of strength, elongation, and flex abrasion resistance. The use of a higher twist multiplier in spinning and plying resulted in PA cotton yarns having improved properties of elongation and flex abrasion resistance.

The unrestricted shrinkage of balanced plied yarns and singles yrrrns i n sotlium hydroxide solution of mercerizing strength was found to increase with increasing twist; the extent of shrinkage and rate of increase were higher for singles yarns than plied yarns. Plied yarns developed high tensions faster than singles yarns when mercerization was carried out without shrinkage. If shrinkages of more than 15% to 20% are permitted, the tension developed is almost too low to measure. This indicates that for fabrics that shrink more than 20% the forces that may cause additional shrinkage are very small and easily restricted. Twist had only niinor effects on the shrinkage of the 72 fabrics of varying warp ends per inch and different yarn structure used in the esperiments. Also the stretch properties were similar. Calculations of filling tightness, espressed as filling cover factor, indicate that a niaxiniuni of approsiniately 16 can be obtained by the slack niercerization of fabrics for filling stretch if the fabric shrinks more than 20%. The conversion of cellulose I to cellulose I1 is more dependent on the temperature of the was11 water than on the amount of unrestricted shrinkage or duration of immersion. T o obtain additional shrinkage in any fabric of a selected weight, it is apparently necessary to use weaves that promote increases in fabric thickness.

A summary of a comprehensive study of the manufacture and finishing of swellingtype water-resistant cotton fabrics of medium weight is presented. These are fabrics which stop the passage of water by the swelling of their constituent fibers. Such stoppage depends upon a zone of very high density flatwise through the fabric. Of many fabrics produced, a few were of swelling type in the grey, but only one after finishing.Variables which are usually given less consideration, had most attention, viz., maturity, and use of very immature cottons; effects of processing the yarn before weaving; and effects of increasing the tightness of fabrics by adding picks up to 36% more than normal. The fabrics were finished in a pilot plant, and an unusual study was made of the effects of successive steps in finishing on air and water resistance.Unique fabrics produced showed unusual properties, especially strength and thickness. Fabrics were evaluated for closing by methods intended to exclude water resistance from other sources than swelling. Many special tests showed that swelling capacity was reduced by finishing, to a greater extent with immature than with mature cottons. The air spaces in dense, grey fabrics of very immature cotton constitute capillary systems of unusually fine pores, especially resistant to the passage of air or water. This advantage over mature cotton is largely offset, however, because the immature cotton loses 4-5% more noncellulosic material when scoured, which leaves more space to fill by swelling. Cottons of average maturity, and from fine to average in fineness, are preferable. Entrapped air in partially swollen fabrics contributed to water resistance beyond the effect of air in ordinary water-repellent goods. This was observed especially in samples swollen in water vapor and may add to the resistance of a fabric in service if exposed to a very humid atmosphere.

Cotton fiber severely damaged by the boll-rot fungus Diplodia sp, was blended with a control white cotton in percentages of 2.5, 5.0, 10.0, and 35.0. Equal amounts of the control cot!on and of these blends were spun with a 3.75 T.M. into 38/1 (16 tex) filling yarns. \Vlth a common warp made from the same control cotton these filling yarns were woven into a 5-hames~, 3-eou~t, filling-faced sateen fabric' (37! in., 64 X 104, 4.37 ?z). The~rab and str~p breaking strengths and resistance to tearing and flex abrasion of fabrics whose filling yarns contained up to 5% of Diplodia fiber were not appreciably lower than those of the fabric having the control cotton in the filling. The large drop in value of these fabric properties when the 35% Diplodia-fiber filling was used was attributed~o the increase in short fiber content of the blend.Spectrophotometric analyses and visual examination of bleached and of bleachedand-dyed samples indicated th~practicality of these finishing operations on cottons containing as much as 10% of Dlplodia-damaged fiber.Field observations suggest that in commercial practice bales containing higher percentages of boll-;ot~amaged fiber th~n are represented by the 5% blend here employed are rare. .Data m~llls and the preced~ng c~mpanion paper indicate that within the range of processing techniques employed Dlplodla-damaged fiber exerts less detrimental effect than might have been anticipated.