Degree of Polymerization of Cellulose in Cotton Fibers

Hessler, Lyle E.; Merola, George V.; Berkley, Earl E.

doi:10.1177/004051754801801004

Cited by 46 publications

(24 citation statements)

References 18 publications

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“…This large MW difference between the components of primary and secondary walls of cotton confirms that previously observed for the cellulose fractions. Hessler et al (1948) determined that the cellulose of immature-fiber samples (primary wall only) had an MW = 960 000, while maturefiber samples contained cellulose with MW = 1 730 000 (DP= 10 650) with the average MW dependent on the stage of development, the variety and location of growth, and the degree of degradation or damage. Marx-Figini (1982) reported that cellulose from the primary wall of cotton has a heterogeneous MW of 325 000-970 000, while the secondary-wall cellulose has an MW = 2 270 000 (DP = 14 000) and is monodisperse.…”

Section: Resultsmentioning

confidence: 99%

“…It has long been recognized that fiber strength is determined by the structural organization of the cellulose chains (Hessler et al 1948); agreement about that relationship, particularly with respect to polymeric, supramolecular and morphological structure varies widely (see Nevell and Zeronian 1985). Thus, our objectives are to understand relationships between fiber strength and the formation of cotton fiber structure and the role of the primary wall in determination of that structure.…”

Section: Introductionmentioning

confidence: 99%

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Analysis of cell-wall polymers during cotton fiber development

Timpa

Triplett

1993

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Abstract.Although the fibers of cotton (Gossypium hirsuture L.) are single cells with a secondary wall composed primarily of cellulose, the cell-wall polymers of the fibers are technically difficult to characterize with respect to molecular weights. This limitation hinders understanding how the fiber wall composition changes during development, particularly with respect to genotypic variations, and how the molecular composition is related to physical properties. We analyzed cell-wall polymers from cotton fibers (cultivar, Texas Marker-l) at several developmental stages (8-60 days post-anthesis; DPA) by gel-permeation chromatography of components soluble in dimethyl acetamide and lithium chloride. This procedure solubilizes fiber cell-wall components directly without prior extraction or derivatization, processes that could lead to degradation of high-molecular-weight components. Cellwall polymers from fibers at primary cell-wall stages had lower molecular weights than the cellulose from fibers at the secondary wall stages; however, the high-molecularweight cellulose characteristic of mature cotton was detected as early as 8 DPA. High-molecular-weight material decreased during the period of 10-18 DPA with concomitant increase in lower-molecular-weight wall components, possibly indicating hydrolysis during the later stages of elongation.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Analysis of cell-wall polymers during cotton fiber development

Timpa

Triplett

1993

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“…The loss of viscosity on weathered cotton indicates cellulose chain rupture through oxidation. Furthermore oxidation may be detected through an alkali boil and subsequent viscosity determination [3]. Copper alkaline solution methods break the oxygen bonds and as a result measure total degradation of cellulose.…”

Section: Discussionmentioning

confidence: 99%

“…Structural changes in the cellulose molecule which have an effect on dyeing occur. Cellulose chain length is decreased [3] and ultimately the utility of the cotton suffers. Previous work [6] on the physical properties of weathered cotton gave indications of length shrinkage which may be interpreted as possible structural changes in the cellulose molecule (crystallinity) .…”

Section: Recommendationsmentioning

confidence: 99%

Chemical Properties of Field-Weathered Cotton

Hessler

Upton

1955

Textile Research Journal

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fectiveness and optimum concentration of finishes used to improve sewability and on their effect on internal needle temperatures. RecommendationsThe data presented in this report suggest that some specific changes in needle design should reduce needle temperatures. The following examples are given :a. The holes should be punched in the needle shank above the eye to increase surface area-to-mass ratio and decrease heat stored by the needle. This would also make cooling during sewing more efficient and make cooling by compressed air more effective.b. The needle shank should be grooved to increase the area exposed to normal air cooling due to machine operation or compressed air cooling and to increase heat dissipation due to radiation. c. Provision should be made for partial internal cooling through the needle butt by compressed air or gas, since needle internal temperatures are higher than surface temperatures during and just after the sewing operation. This paper deals with the chemical changes in cotton fiber through field weathering. The chemical changes which occur are important for several reasons.Structural changes in the cellulose molecule which have an effect on dyeing occur. Cellulose chain length is decreased [3] and ultimately the utility of the cotton suffers. Previous work [6] on the physical properties of weathered cotton gave indications of length shrinkage which may be interpreted as possible structural changes in the cellulose molecule (crystallinity) .Marsh and coworkers [9] have published extensively on cotton-weathering research. In the publication cited, they have also reviewed the literature.Work undertaken here attempts to evaluate weathered cotton through chemical tests. The early cotton was field weathered up to 5 mo, whereas the later cotton was in the field for more than 2 mo. Since cotton varies in composition from early to late opening, an additional weathering variability has been added to cotton-weathering research. ExperimentalThe field plans of the experiment were given in a previous publication [6] and will not be repeated here.Degree of polymerization determinations were made by forming cellulose nitrate and dissolving the nitrate in butyl acetate. The intrinsic viscosity was calculated from the equation of Baker as modified by Philippoff [11] ] in which [~] = 8/c (1]r1/8-1). A correction in intrinsic viscosity was made for incomplete nitration by the method suggested by Lindsley [8]. Degree of polymerization was derived from the Staudinger expression DP = K [q] where K = 118 for cellulose nitrate in butyl acetate. The value of K was chosen after the review of the literature. This constant affected the magnitude of the DP value but plays only a small part in weathered difference in DP calculations.Copper reduction values and aqueous-extract pH were run according to the methods outlined by Marsh [9]. Carboxyl groups were determined by the method of Pacsu [7], in which an excess of dilute NaOH is 1 Fiber and Spinning Laboratory of the Cotton Research Committee of Texas.

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“…of wastes in the original work [9] invalidates the conclusions, on the basis that high molecular weight materials might have been concentrated in the wastes. However, it is known that immature fibers are concentrated in the picker wastes, and the work of Hessler, Merola, and Berkley [7] indicates the molecular weight of the cellulose in immature fibers to be about half that of mature fibers obtained from the same source.…”

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Degradation of Cellulose During Mechanical Processing

Whitwell

Lemiszka

Hughes

1951

Textile Research Journal

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Previous work [9] on the degradation of cotton during mechanical processing has been extended to include a study of the action of the pickers under various operating conditions. The results indicate that blade and carding beater types cause different amounts of degradation, that the amount of degradation caused by a very close setting can be differentiated from that due to wider spacings, and that the speed of rotation of the beater has a degradation effect which is detectable only after several passes—i.e., several consecutive picker operations. The effect of consecutive picker operations under similar conditions of the other variables is readily discernible. IN A RECENT INVESTIGATION [9] it wassuggested that cotton degrades during the normal processing operations which convert the seed cotton to yarn. Evidence of this degradation was based upon the progressive reduction in D.P. of a given cotton as it was mechanically processed, the viscosity of cotton in cupriethylene diamine being used as an index of D.P. Hess et al. [6] and Forziati et al. [5] have also reported reduction of D.P. of cellulose during purely mechanical treatment, although the results in both of these cases were obtained on much more drastic treatments. All three of the reports cited concluded that mechanical energy could be absorbed by the cellulose and utilized to break valence bonds.In the light of these conclusions, it seemed desirable to extend the experimental work, concentrating on the damage incurred in a single operation, with specific study of controllable variables in the operation. In the work presented here, special attention was given to the action of the beaters in the picking operation, since previous evidence showed [9] that this operation was the most drastic in causing degradation. The Saco-Lowell Shops processed the cotton to provide information on the effects of beater type, speed (r.p.m.), setting, and repetition of passes through beating equipment.It has been argued that the damage during mechanical processing is not important with respect to that which occurs during later chemical processes such as kier-boiling or bleaching. However, a recent paper which reported studies on rain-grown and irrigated cottons [10] does not support this argument. Observed D.P. differences on samples from two stages of mechanical processing indicated degradation but were not large enough to be statistically significant (probably due to sensitivity of the method employed, which was entirely adequate for the purposes intended). However, after these samples of card sliver and combed yarns had been given identical scouring treatments, significant differences existed. Thus, although the data are not extensive, there is strong statistical evidence to indicate that the small changes in D.P. incurred during mechanical processing persisted and were not lost in the subsequent chemical treatments. An appreciable portion of the difference in D.P. of the two raw cottons also persisted through the mechanical and chemical treatments. Further experimen...

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Degree of Polymerization of Cellulose in Cotton Fibers

Cited by 46 publications

References 18 publications

Analysis of cell-wall polymers during cotton fiber development

Analysis of cell-wall polymers during cotton fiber development

Chemical Properties of Field-Weathered Cotton

Degradation of Cellulose During Mechanical Processing

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