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Showing 1 to 20 of 75 for “"degree of polymerization"”.
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Solubility of cellulose nitrate as a function of the degree of polymerization
A sample of cellulose nitrate was to be fractionated into a series of fractions differing from each other with respect to the degree of polymerization. The method chosen was to be one which would give a large number of fractions, each one attaining as high a degree of homogeneity with respect to …
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Effects of fructan source and degree of polymerization on intestinal barrier function and histomorphology characteristics in obese C57BL/6 mice
… decrease systemic inflammation. The objective of this study was to test the effects of prebiotics on intestinal permeability, morphology, and gene expression in an obese mouse model. Obese, 18-wk old, C57BL/6 mice were randomized to high-fat (45% of kcal) diets containing 5% cellulose, 10% …
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An attempt to relate the surface tension to the concentration and the degree of polymerization of nitrocellulose dissolved in n-butyl acetate
On the basis of the present data it would seem that there is no marked relationship between the surface tension and the degree of polymerization of nitrocellulose solutions of normal butyl acetate as determined by the Du Nouy method. It should be noted that no great precision is present in the …
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A Systematic Study of Sialic-Acid-Containing Poly(styrene sulfonate) for Antiviral Applications
This dissertation presents the development of a versatile and modular synthetic platform for constructing functional copolymers using post-polymerization modification (PPM) of activated esters. By decoupling the synthesis of the polymer backbone from the introduction of functional groups, this …
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The fractionation of cellulose xanthate by means of its derivatives
… it may be said that contrary to the results of the fractionation obtained from the fractionation of cellulose xanthate diethylacetamide by Fink, Stahn, and Matthes; the results obtained here indicate that there is a definite variation of the degree of substitution from fraction to fraction. …
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Dielectric investigations of the effect of precipitant addition to cellulose nitrate solutions
The prime result has been the development of an experimental procedure for producing a definite dielectric effect when water is added to an acetone solution of cellulose nitrate. This effect depends not only on the purity, dryness and concentration of the cellulose nitrate, but also on the average …
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Living cationic polymerization
The kinetics of the polymerization of styrene iniated by 1-chloro-1-phenyltehane/tin (IV) chloride in the presence of tetrabutylammonium chloride have been studied. Dilatometry studies at 25 °C were conducted and the orders of reaction were established. Molecular weight studies were conducted for …
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Chemical composition and fiber structure as factors affecting fiber fermentation
… (HPLC) technique for the analysis of monosaccharides was developed. Procedures using sulfuric acid as the hydrolytic agent were superior compared to a procedure using trifluoroacetic acid. The HPLC technique, involving anion exchange chromatography and pulsed amperometric detection, …
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Cellulose fiber dissolution in sodium hydroxide solution at low temperature: dissolution kinetics and solubility improvement
… can even dissolve cellulose in a narrow range of the phase diagram. It was found that for cellulose with low to moderate degree of polymerization, the maximal solubility occurs with 8~10% soda solution. In recent years, researchers found that sodium hydroxide with urea at cold temperature can …
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Effects of Methyl Cellulose on the Cellulolytic Bacterium, Ruminococcus Flavefaciens (Rumen, Anaerobe)
… by highly substituted methyl celluloses (degree of substitution > 1.5 and mol wt > 12,000). The inhibitory response was concentration dependent with 0.1% (wt/vol) or methyl cellulose required for complete inhibition. R. flavefaciens was unable to use methyl cellulose for growth and no …
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Liquid State Theory of Equilibrium Structure and Thermodynamics of Block Copolymer Melts and Solutions
… to study the thermodynamics and structures of fluids of multiblock polymers both with nonpolar and strongly attracting groups. The physical clustering/aggregation process is probed via the calculation of small and wide angle scattering patterns, real space intermolecular radial distribution …
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Polymer Dispersity Affects Conformation of Brushes Grafted on Nanoparticles
… due to uniform dispersion and/or morphology of polymer brushes with varying chain conformation. Polymer brush properties, such as grafting density \sigma and degree of polymerization N, can drastically affect conformation of neutral and pH-responsive PGNPs and further influence their efficacy …
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Determination of conditions for fractionation of ethyl cellulose
Many of the properties of ethyl cellulose that make it useful in different ways are a result of the varying lengths of the cellulose chains arranged within the chain bundles. This investigation was undertaken in order to find a method of separating these ethyl cellulose chains into more homogeneous …
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Structure-property relationships of multiphase copolymers
… on the theoretical and phenomenalogical aspects of starblock, di- and tri-block copolymer systems with very narrow molecular weight distributions. However, in many real multiblock systems the effect of such variables as; chemical composition distribution, molecular weight distribution and block …
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The cationic ring-opening polymerization of cyclic ethers
The kinetics and mechanisms of ring opening polymerization and copolymerizntion of different cyclic ethers were studied using mainly a cationic system of iinitiation. BF30Et2/ethanediol. The cyclic ethers reacted differently showing that ring strain and basicity are the main driving forces in …
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Poly(β-Gal-Thr): A New Scalable Synthetic Mucin
<p>A method for the preparation of glycosylated polypeptides via the nucleophilic ring-opening polymerization of a glycosylated <em>N</em>-carboxyanhydride (NCA) monomer is reported. The synthesis of 2,3,4,6-tetraacetyl-<em>β</em>-galactose-threonine <em>N</em>-carboxyanhydride …
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Absorption and utilization of oligosaccharides by Cellvibrio gilvus
The ability of a cellulolytic bacterium Cellvibrio gilvus, to absorb and utilize members of the cellulose oligosaccharide series was investigated. Resting cell suspensions prepared from 24-hour cultures were incubated with the cellulodextrins. At various times samples were removed from the …
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ΣΥΓΚΡΙΤΙΚΗ ΜΕΛΕΤΗ ΤΟΥ ΕΡΠΥΣΜΟΥ ΜΕΤΑΞΥ ΧΗΜΙΚΩΣ ΠΟΛΥΜΕΡΙΖΟΜΕΝΩΝ ΚΑΙ ΦΩΤΟΠΟΛΥΜΕΡΙΖΟΜΕΝΩΝ ΣΥΝΘΕΤΩΝ ΕΜΦΡΑΚΤΙΚΩΝ ΡΗΤΙΝΩΝ
THE CREEP OF MICROSPECIMENS OF THREE CHEMICAL INITIATED AND THREE PHOTO INITIATED COMPOSITE RESINS WAS STUDIED USING A TORTIONAL CREEP APPARATUS IN A STATIC METHOD. THE ABOVE MATERIALS IN PAIRS HAVE THE SAME CHEMICAL COMPOSITION AND FILLER CONTENT AND DIFFER ONLY IN THE MANNER OF POLYMERIZATION. …
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