Verne W. Tripp

Some Observations on the Constitution of the Primary Wall of the Cotton Fiber

The primary wall of fully matured cotton fibers has been isolated and its morphology and composition studied by electron microscopic examination and by chemical analyses. The pri mary wall appears to contain about 50% cellulose; protein, wax, and pectic substances occur in lesser amounts; cutin or suberin and mineral matter are also present. The concentration of noncellulosic substances in the primary wall is much greater than in the whole fiber. Electron microscopic examination of the primary wall indicates that it consists of a network of cellulose fibrils, having diameters of 100-400 Å, surrounded by the noncellulosic constituents. The oriented fibrillar systems observed with the polarizing microscope have not been seen in the electron micrographs of the specimens studied. There is an apparent increase in the diameter of the fibrils of the primary wall and in the denseness of the network as the fiber matures. The existence of layers in the cellulose network has been observed.

X-Ray Fluorescence Analysis of Modified Cottons

The application of x-ray emission techniques to the qualitative and quantitative elemental analysis of chemically and additively modified cotton textiles has been investi gated. Sample preparation and calibration techniques which appear to be suitable for the analysis of textile materials have been devised. The method has been applied to a variety of samples containing some 20 individual elements. The technique is useful for identifying the elements present in fabrics finished with poorly defined agents. It has been applicable to problems involving the add-on and subsequent loss of fungicidal agents containing such elements as Cd, Zn, Se, Cl, S, and P. Typical results obtained with a number of modified cottons are given.

The Effect of Cellulase on the Degree of Polymerization of Cellulose and Hydrocellulose

On acid hydrolysis of cotton, the degree of polymerization (DP) of the insoluble residue falls rapidly to a low level (leveling off DP). Continued hydrolysis results in further losses in weight, but the DP, and the micelle dimensions, remain unchanged. Immergut and Rånby [6] suggest that individual micelles at the leveling off DP disap pear in entirety; i.e., further action of acid yields soluble fragments only. The present investigation was undertaken to compare the action of enzymes on the micelles with that of acids. The study was broadened by the inclusion of hydrocelluloses from cottons treated in various ways, and further extended to include the parent materials from which the hydrocelluloses were prepared.

Studies on the Cross-Linking of Cotton Cellulose: Part II: Microscopical Observations

1. Anslow. W. P., Karnofsky, D. A., Jager, B. V., and Smith. H. W., J. Pharmacol. Exptl. Therap. 93, 1-9 (1948). 2. Reeves, W. A., Drake, G. L., McMillan, O. J., and Guthrie, J. D., TEXTILE RESEARCH JOURNAL 25, 41-46 (1955). 3. Reeves, W. A., Perkins, R. M., and Chance, L. H., TEXTILE RESEARCH JOURNAL 30, 179-192 (1960). 4. Schoene, D. L. and Chambers, V. S. (to U. S. Rubber Co.), U. S. Patent 2,524,399 (1950). 5. Stahmann, M. A., Golumbic, C., Stein, W. H., and Fruton, J. S., J. Org. Chem. 11, 719-735 (1946).

Some Studies on the Cross-Linking of Cotton Cellulose Part I: Chemical and Physical Aspects

The currently-used types of cross-linking agents and some of their effects on cotton are discussed. The primary weaknesses or shortcomings of the finishes achieved with these agents are pointed out. It can be concluded either that the ideal cross-linking agent for cotton has not been found or that the best technique of application has not yet been discovered. However, considerable success is being had in producing minimum- care fabrics by the use of many cross-linking agents, especially the N-methylol type. Although cross links through primary covalent bonds are largely responsible for the observed physical changes in cross-linked cotton fiber, secondary valence cross links also may produce significant changes, some of which appear to be rather durable. Evidence is presented which indicates that polymer formation produced concurrently with cross-linking improves the over-all minimum-care properties of cotton fabric, although polymer formation alone does not improve the wrinkle recovery. Cross-linking agents which are capable of forming thermosetting resins generally are required in somewhat larger add-ons to produce wrinkle recovery angles in the practical range than are those agents that do not form thermosetting resins. The extent of permanent set is related to the extent of cross-linking. Moisture regain and density of the cross-linked cottons are more dependent upon the state of fiber swotting at the time of cross-linking than upon the extent of cross-linking.

The Surface of Cotton Fibers Part I: Native Fibers

The topography of unmoditied cotton fibers has been examined microscopically by means of surface replica techniques. The outstanding characteristic of the surface is a system of roughly parallel ridges and grooves spiraling around the fiber at an acute angle (usually 20 30 ) to its axis. The pattern of the surface is a reflection of the spiral fibrillar structure of the cellulose beneath the primary wall of the fiber. The average height and distance between ridges is approximately 0.5 micron. and many of the ridges are 10 or more microns in length. The surfaces of most native cottons are quite similar, although statistically significant differences in the average distance between ridges were found between certain samples The surface of fibers from unopened bolls is relatively smooth, but assumes the roughness of the typical fiber on drying for the first time. A characteristic surface formation ap peared to be associated with fibers known to have undergone compression. Drastic abrasion largely obliterates the normal appearance of the fiber surface.

Thermal Degradation in Tire Cords Part I: Effects on Strength, Elongation, and Degree of Polymerization

of any mechanical action. No attempt is made to answer the question concerning any possible mechanical degradation, such as has been observed under certain conditions by others [7, 10, 12], inasmuch as such mechanical degradation in road operation is inextricably bound up with the heat produced at the same time. The present investigation was designed to amplify and, if possible, explain the earlier work of Conrad, Lyons, and Tripp [3] which showed that cotton tire cords taken from tires that

Microscopical Observations on Partially Acetylated Cottons and Related Fibers

Effects of acetylation on the morphology and submicroscopic structu e of cotton have been studied by light and electron microscopy. The cross-sectional area of partially acetylated (PA) fibers increases with degree of substitution. The average refractive index of PA cotton decreases with increase in acetyl content, as do the indices measured parallel and perpendicular to the fiber axis. Refractive index measurement appears to be a feasible method for estimating the chemical composition of PA cotton. At early stages of esterification, unevenness of reaction along the length of fibers may be demon strated by dyeing and swelling techniques. Acetylation causes the surface of cotton to become smoother, and obliterates the micro- fibrillate pattern characteristic of scoured fibers. PA cotton fibers swell when embedded in methacrylic esters by polymerization. The swelling causes separation of the lamellae of the secondary wall, and permits electron microscopical observations on the interior elements of the fiber to be made on thin cross sections of the specimen. Fragments of PA cotton obtained by wet- beating show progressive loss of the fibrillate character of unacetylated cellulose as the acetyl content increases. At high degrees of substitution, the PA cotton fragments resemble the spongy particles obtained from wet- beaten acetate rayon and Arnel. The results of microscopical examination are considered in terms of fiber structure.

Survey of effects of variety and growing location of cotton on card room dust composition

Electrostatically precipitated respirable dusts from six major U.S. varieties and growing areas were analyzed. From 81-95% by weight, was under 15 micronm diameter. Composition was affected more by growing location than by variety. Dusts contained 16-28% ash, 8-9% moisture, and 62-76% organic matter, including 16-31% protein and 2-12% cellulose. Inorganic composition reflected soil type and minerals. Major elements were silicon, calcium, potassium, phosphorus, magnesium, and aluminum. Infrared spectra of dusts resembled proteins, but water extract spectra did not. Possible implications concerning byssinosis are discussed.

Convenient Adjustment to a Standard Velocity Gradient of the Fluidity of Anomalous Cuprammonium Solutions of Cellulose

Although structural viscosity has been recognized for many years and has been intensively studied since about 1930, a satisfactory theoretical and experimental basis for dealing with the viscosity of linear high polymer solutions has not been found Of the great mass of data on the subject published in the literature, few can serve a permanent purpose because not all the conditions necessary for interpretation have been recorded. Yet by continued attack and by study of such findings as those of Peterlin