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  • 1
    Electronic Resource
    Electronic Resource
    The behaviour and photoresponses of some indolinospiropyrans in monomolecular films (1984)
    Springer
    Colloid & polymer science 262 (1984), S. 481-488 
    Details
    ISSN: 1435-1536
    Keywords: Photochromism ; Photoresponses ; Spiropyrans ; Monomolecular Layers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Surface pressure-area isotherms of two spiropyrans were determined under different conditions of illumination. It was found that the photomerocyanine forms produced stable films whilst this was not always the case with the spiro forms. Photomerocyanine monolayers were stabilized by the polar aqueous subphases and photoinduced ring-opening could be effected on the water surface by U. V. irradiation. The ring-closing reaction, however, was inhibited in monolayers. Photomechanical responses occurred as a consequence of the spiropyran → photomerocyanine reaction and these were catalysed on acidic subphases. Factors influencing the magnitude of such responses were assessed. Photoregulation of surface tension at the air-water interface was inferred from measurements on stearic acid monolayers spread on ‘photochromic subphases’.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01412045
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  • 2
    Electronic Resource
    Electronic Resource
    Eine spektroskopische Untersuchung von Phenylhydrazin-Derivaten der Amylose (1977)
    Springer
    Colloid & polymer science 255 (1977), S. 1038-1038 
    Details
    ISSN: 1435-1536
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01776383
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  • 3
    Electronic Resource
    Electronic Resource
    The adsorption of dyes in chitin. III. Intraparticle diffusion processesCorrected proofs received March 11, 1983 (1983)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 28 (1983), S. 1767-1778 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Intraparticle diffusion processes for the adsorption of dyestuffs onto chitin have been studied. The amount of dye adsorbed per gram of chitin has been plotted against the square root of time. The slope of this plot is linear and has been defined as a rate parameter k. This rate parameter has been determined for a number of process variables, including initial dye concentration, agitation, chitin particle size, chitin mass, temperature, and solution pH. However, sometimes two and even three linear regions are apparent on the root time plots indicating a possible branched pore mechanism. The controlling mechanisms are due to macropores and micropores in the chitin particle creating rapidly and slowly diffusing regions.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1983.070280519
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  • 4
    Electronic Resource
    Electronic Resource
    Studies on modified chitosan membranes. I. Preparation and characterization (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 46 (1992), S. 255-261 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Chitin was isolated from prawn shells, and chitosan was prepared from it. The degree of N-deacetylation and the molecular weight were determined using IR spectroscopy and viscometry, respectively. A series of different modified chitosan membranes were prepared by blending with polyvinylpyrrolidone (PVP). These membranes were characterized by various techniques, including differential scanning calorimetry (DSC), wide-angle X-ray diffractometry (WAXD), and tensile testing. The physical, thermal, and mechanical properties were evaluated, and the change in these properties upon the addition of PVP into the blends has been discussed in terms of the amorphous and hydrophilic nature of PVP. Hydrophilicity of the blends increases due to the presence of PVP in the chitosan substrate. This helps in breaking the hydrogen bonds in between chitosan molecules and causes the blends to swell in three dimensions.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1992.070460206
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  • 5
    Electronic Resource
    Electronic Resource
    Studies on modified chitosan membranes. II. Dialysis of low molecular weight metabolites (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 46 (1992), S. 263-269 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The permeabilities of low molecular weight metabolites were determined through chitosan and a series of chitosan - poly(vinyl pyrrolidone) (PVP) membranes. The dialysis studies were carried out in vitro using a diaphragm-type test cell. The basic metabolites (urea, creatinine, and glucose) show higher permeation rates than do the acidic metabolites (uric acid and phosphate) through all the modified membranes. The hydrophilicity of the membranes, molecular weight, and chemical nature of the metabolites were important parameters in determining transport properties of the membranes. It was observed that higher permeation rates can be obtained by manipulating the amount of PVP in the blended membranes. The PVP weight loss in the aqueous medium was negligible.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1992.070460207
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  • 6
    Electronic Resource
    Electronic Resource
    Spectroscopic investigation of cellulose degraded celluloses, and their phenylhydrazine derivatives in relation to assessment of degradation (1972)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 16 (1972), S. 3063-3071 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The ultraviolet absorption spectra of Cadoxen solutions of hydrocellulose and hydrocellulose phenylosazones are described. With solutions of hydrocellulose no simple relationship between D.P. and absorbance was found. Solutions of hydrocellulose phenylosazone in Cadoxen show well-defined maxima at 277 nm and 390 nm and do not change over 1 hr when oxygen is excluded. The absorbance of the phenylosazone at 390 nm may be used to determine the D.P. of the hydrocellulose samples.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1972.070161202
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  • 7
    Electronic Resource
    Electronic Resource
    Adsorption of dyes on chitin. I. Equilibrium studies (1982)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 27 (1982), S. 3043-3057 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Equilibrium isotherms have been studied for the adsorption of four dyestuffs, namely, Acid Blue 25, Acid Blue 158, Mordant Yellow 5, and Direct Red 84, onto chitin. Langmuir and Freundlich constants have been determined and the effects of chitin particle size and solution temperature have been investigated. Theoretical isotherms have been compared with experimental data and good agreement was obtained using a composite isotherm of the general form: Ye = iCe/(1 + jCem), where i,j, and m are constants.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1982.070270827
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  • 8
    Electronic Resource
    Electronic Resource
    Adsorption of dyestuffs onto chitin. External mass transfer processes (1982)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 27 (1982), S. 4251-4261 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The effect of several variables on the adsorption rate of four dyestuffs onto chitin was studied. A model is proposed enabling the film mass transfer coefficients to be determined. The coefficients were independent of initial dye concentration, chitin mass, chitin particle size, and temperature; a slight dependence with agitation was obtained. The film mass transfer coefficients at 400 rpm were 2.8×10-3, 2.9×10-3, 3.9×10-3, and 0.9×10-3 cm/s for Acid Blue 25, Acid Blue 158, Mordant Yellow 5, and Direct Red 85, respectively.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1982.070271116
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  • 9
    Electronic Resource
    Electronic Resource
    Spectroscopic investigation of hydrocellulose phenylosazones in cadoxen solution (1974)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 18 (1974), S. 1187-1195 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Solutions of hydrocellulose phenylosazone in cadoxen are stable when oxygen is excluded. In the presence of oxygen, the absorption spectrum changes, but the change is partially reversible when nitrogen is bubbled through the oxidized solution. It is probable that a hydroperoxide of the hydrocellulose phenylosazone is formed initially and is then decomposed by the basic solvent. The work indicates the importance of using deoxygenated solvents and working in an oxygen-free atmosphere when preparing cadoxen solutions of hydrocellulose phenylosazone.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1974.070180417
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  • 10
    Electronic Resource
    Electronic Resource
    Spectroscopic investigation of reducing endgroup derivatives of hydrocellulose (1975)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 19 (1975), S. 2423-2430 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A series of reducing endgroup derivatives of hydrocellulose have been prepared and their suitability for spectroscopic endgroup analysis examined. Of the compounds examined, the semicarbazide, thiosemicarbazide, hydroxylamine, benzimidazole, ethylacetoacetate, nitrophenylhydrazine, and phenylosotriazole derivatives were for one reason or another unsuitable. The phenylhydrazine-p-sulfonic acid derivative has properties which would make it suitable for endgroup analysis, but unfortunately neither the glucose nor the cellobiose derivative could be prepared. The 1-phenylflavazole derivative, however, appears to be very suitable for endgroup analysis.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1975.070190906
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