Browsing by Author "Watson, J. W."
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- Effect of degree of acetylation on mechanical properties of cellulose acetate filmsAwni, Adnan Husayn (Virginia Tech, 1956-06-12)Four samples of cellulose acetates having degrees of combined acetic acid between 50.8 - 55.8% were fractionated to obtain sharp fractions or approximately the same degree of polymerization. About 2000 grams starting material of each sample of cellulose acetate were needed to obtain approximately 50 grams or sharp fraction for testing the mechanical properties of their films. Fractionation of the cellulose acetate was from an acetone-water mixture, by addition of n-heptane to precipitate a certain traction. After a series of refractionations, a sharp fraction of each of the four cellulose acetates was obtained. These fractions had different degrees of acetylation but approximately the same degrees of polymerization. These fractions were then dissolved in acetone and cast into films which were conditioned for three days and their mechanical properties were determined in an attempt to determine the effect of degree of acetylation on the mechanical properties. It was found that the degrees of acetylation of the various sharp tractions of cellulose acetates had no appreciable effect on the mechanical properties of their films. It was concluded that the degrees of polymerization of the various fractions were so high that the effect of the degree or acetylation on the mechanical properties could not be detected. The degrees of polymerization of the various samples were determined by the viscosity method using acetone and cupriethylenediamine as the solvents, It was found that the degrees of polymerization of the various samples of cellulose acetates determined by the cupriethylenediamine viscosity method were almost four times greater than the degrees of polymerization of the same samples determined by the acetone viscosity method using constants obtained from the literature.
- Reactions of cellulose in liquid sulfur dioxideBrooks, Lawrence Cornelius (Virginia Tech, 1942-06-29)It appears impossible to nitrate cellulose in a medium of liquid sulfur dioxide either ~~th ruming nitric acid, a mixture of fuming nitric acid and sulfuric acid t a mixture of fuming nitric acid and phosphorus pentoxide, a mixture of fuming nitric acid, phosphorus pentox1de ana chlorine gas, or with nitrogen tetroxide. This is attributed to the fact that in each case the primary reaction ist hat of the formation of the compound N23209.
- The reducing action of different metals in liquid ammoniaHsieh, George Jay (Virginia Tech, 1951-06-05)A systematic investigation of the reducing action of different metals on an organic compound in liquid ammonia is reported for the first time.
- A selective fractionation of cellulose nitrateLou, Li-Hsi (Virginia Tech, 1951-06-15)It has been shown that reproducible selective fractionation so as to separate a desired D. PO. Polymer from 5 different samples of cellulose nitrate, covering a D.S. Range of 10.97-13.35%-N, has been accomplished.
- A study of the crease-resistance of viscose rayonSugarman, Nathan (Virginia Tech, 1942-05-01)Crease-resistance is a very greatly desirable property in textile fibers. Of the natural fibers, wool exhibits this property to the greatest degree, followed by silk, cotton, and flax, which has a very low crease-resistance. The artificial cellulose fibers fall considerably below wool and silk in this respect. The improvement of the crease-resistance of rayon and other fibers has been sought in various after-treatment processes, in which substances are either deposited within the fiber, or react with it. There are numerous patents (22) for such methods of imparting crease-resistance. It would be highly desirable if the crease-resisting powers could be achieved "by a modification of the intrinsic properties of a fiber, that is, by producing a fiber which already is crease-resistant. The purpose of the work reported here was to attempt to produce a viscose rayon fiber with better crease-resisting properties, and to study the effect of a variation in the cellulose chain length distribution in the rayon upon this property. This work was done under a Fellowship of the Behr-Manning Corporation, Troy, New York.
- A study of the methods of determination of the rare earth elements in a substance with a high concentration of calcium and phosphates and the application to human bonesHoover, Roger Kent (Virginia Tech, 1951-11-05)A method for determining the rare elements in bones and similar materials includes [eight] steps.
- A study of the preparation of some 10-dimethylphenyl-1,2,-benzanthracenesBorkovec, Alexej B. (Virginia Tech, 1953-12-05)It is the purpose of this thesis to further investigate the reaction suggested by Bradsher, and the preparation of some 10-dimethly-phenyl-1, 2-benzanthracenes.
- A study of the relationship between the molecular structure of DDT and its insecticidal activityBuese, George J. (Virginia Tech, 1951-11-05)Three reaction paths (Charts II, III and IV) have been shown for the preparation of the following three compounds which are of interest because they are structurally related to DB2: 9â tri-chlormethylanthracene, 3-chloro-9-â ¢trichlomethylanthracene and 2,7-dichloro·10-trichlomethylanthracene.
- A study of the sulfur-cellulose ratio of viscose at maturityChinai, Suresh Natvarlal (Virginia Tech, 1951-06-06)The effect of acetic acid on the cellulose content of viscose is negligible upon standing. The sodium zincate method fails to give satisfactory results in the determination of initial sulfur:cellulose a ratio in the crumbs.