Lyle E. Hessler

Degree of Polymerization of Cellulose in Cotton Fibers

* Division of Cotton and Other Fiber Crops and Diseases, Bureau of Plant Industry, Soils and Agricultural Engineering, Agricultural Research Administration, U. S. Department of Agriculture, Beltsville, Md. † National Cotton Council of America, Washington, D. C. THE PHYSICAL PROPERTIES of cotton are dependent on the fiber structure and shape. Their use value is also influenced by the appearance of the fibers and the products made from them. Fiber

Degree of Polymerization, Spiral Structure, and Strength of Cotton Fiber

Cotton fiber from bolls collected on opening and dried in the laboratory without exposure to direct sunlight were tested for the following fiber properties: fiber length, fineness, strength, spiral structure, and degree of polymerization (D.P.). When these individual properties were each correlated with the Pressley strength index in simple correlations, the spiral structure and Pressley strength index gave the highest r values, and the degree of polymerization and Pressley index the second highest. For variety effects, the D.P. and Pressley index gave a higher coefficient of correlation than the spiral structure and Pressley index. Significant r values were obtained between fineness and Pressley index for total and variety effects, between fineness and D.P. for all effects, and between spiral structure and D.P. for all effects. Further more, a significant r value was found when fiber length was correlated with chain length (D.P.) for total over-all effects. It is concluded that the length of the cellulose molecule (D.P.) is an important factor in the physical properties of cotton fibers. All multiple correlations, including the fiber properties used in the simple correlations, were highly significant for varieties within locations and for over-all effects. Spiral structure and chain length (D.P.) when correlated with Pressley strength gave the highest coefficient of correlation.

The Effect of Temperature on the Physical and Chemical Development of Cotton Fiber

ntent ly (letiittirizttioti nf the tilwr cell l~lawr.t prutcin and inactiB’ati<m of the· enz~ 111(’.... ttmrtimnity in rrllttIme synthesis, ~l~cwolwratttrc· in the cotton hull can very wt,l1 rise t<’ 120 F. on hot day...., as sh<’BBn Iv Anderson j I 11. That physical properties will also he atTt’dt’d Iv heat has been <!en)otjstrate<! Iv Hesster 141 I wht’f(’ excessive heat attecte<) cottot) hher (te B’t’’’’pl1lt’nt Iv producing nher <if shorter length, 1~1BB(’r fint’t1t’~&dquo;&dquo;, awl greater ~t f(’n~t h For n numlwr mf years the Cotton Division of the t’.S. Department of .:B~;ricttltt4rc· ccmclurtt·cl extensive _ rcyimtta) variety tests on cotton, the tests shoBB the effect llavrcl l~t enviromnent on the nher properties and ~litttttn~; performance of cotton These data have been stxnmari/ed in the L S D A pnhhcation Hdtcr (’uttons I U 1, _

The Effect of Weathering in the Field on the Fiber Properties of Cotton

The influence of a number of factors on the behavior of a ring-spinning system has been investigated theoretically. The factors are traveller weight, the coefficients of friction between the ring and the traveller and between the yarn and the traveller, and bobbin speed. Bobbin tension always increases with increasing traveller weight, and usually also with increasing coefficient of friction between the ring and the traveller. Variations of friction between the yarn and the traveller are less important in the range corresponding to practical conditions. There is an upper limit to the coefficient of friction between the ring and the traveller above which spinning appears to be impossible. Also, for the higher values of the coefficient of friction between the yarn and the traveller, it is necessary for the frictional coefficient between the ring and the traveller to exceed a certain value.

The Relationship Between Cotton Fiber Development and Fiber Properties

Two long staple cottons, differing in fiber bundle break elongation but having other pertinent fiber properties substantially equal, were blended in different percentages to permit a study of the effects of break-elongation on yarn properties and spinning etbciency. Yarn strength and elongation were affected by fiber elongation, with fibers having the highest fiber elongation exerting the greatest influence. Furthermore, nep formation increased linearly as the percentage of higher elongation cotton increased in the blend, indicating that neps are directly influenced by average fiber stiffness. It was also found that yarn toughness index correlated closely with yarn impact data, thus suggesting its possible substitution for yarn impact data. The inconsistency of end breakage of the warp and hlling yarns during spinning offered no conclusive evidence as to the relative spinnability of the cottbns and cotton blends investigated.

A Card Study on Production Cotton for Coarse Goods

PRODUCTION COTTONS are the shorter staples which go into coarse goods such as ducks, drills, Osnaburgs, and coarser sheetings. In coarse goods, yarn appearance is not as great a factor as in quality goods, largely because the irregularities are not too often noticeable in the finished product. Thus, the optimum carding rate is very important both from a cost basis and from the basis of the quality of the finished product. For this reason, a carding study

A Mechanized Fiber Blender

cotton are apparent to many fiber technologists. Variations in fiber properties have been demonstrated over the fiber, seed, lock, plant, field, and growing season. These variations, together with damage to fiber caused by weathering, which can be very irregular, make the blending and sampling of cotton for physical testing very important. As increased instrument testing for fiber properties becomes more and more common in the textile industry, fiber sampling, fluffing, and blending can no longer be ignored where instrument accuracy is required. The axiom, &dquo;accuracy of physical testing can be only as good as sampling,&dquo; is still a very good criterion to follow in any fiber analysis. Many laboratories sample cotton by hand, which is extremely tiresome and time-consuming. More-

Study on Picker Performance

An instrument is described for measuring the uniformity of picker laps and studying the per formance of the pedal-type evener device. Studies indicate that the performance of the evener is reasonably good as a yard-to-yard evening device, but less effective for within-yard variations.