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  • Polymer and Materials Science  (6)
  • Biochemistry and Biotechnology  (3)
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  • 1
    Electronic Resource
    Electronic Resource
    Influence of structure of cyclic urea derivatives on their reactivities with cotton (1969)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 1949-1963 
    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 structure of the cyclic urea influenced the rate of reaction with cotton cellulose and the mechanism by which reaction occurred. Reaction of N, N′-dimethylolethylene-urea (DMEU) and N, N′-dimethylolpropyleneurea (DMPU) with cellulose in presence of inorganic salt catalysts proceeded through methylol hydroxyls and at the same rate; but reaction mechanism differed. With DMEU, N → metal ion coordination occurred and SN2 mechanism prevailed. With DMPU, O → metal ion coordination resulted.Reaction of dihydroxyethylene urea (DHEU), N, N′-dimethyldihydroxyethyleneurea (DMeDHEU), and N, N′-dimethyloldihydroxyethyleneurea (DMDHEU) with cotton cellulose proceeded through ring hydroxyls with the formation of a carbonium ion, indicating an SN1 mechanism. The much faster rate of reaction with DMeDHEU than with DHEU was attributed to the more electronegative environment of its ring hydroxyl, while the much slower rate of reaction of DMDHEU was attributed to hydrogen bonding between its methylol and ring hydroxyls.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1969.070130914
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  • 2
    Electronic Resource
    Electronic Resource
    Fabric properties of butadienediepoxide-treated cottons as affected by liquid ammonia pretreatments (1976)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 20 (1976), S. 1905-1920 
    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: Effects of liquid ammonia and mercerizing-strength caustic as pretreatments upon textile properties of cotton sheeting modified with butadienediepoxide (BDO) catalyzed by 2% and 15% NaOH were compared. Tensile properties of the NaOH-mercerized control (CM) (celluloses I and II) greatly exceeded those of native (cellulose I) and ammonia-treated (NH3) controls. NH3(I) and NH3(III) are those cottons having the cellulose I and mixed cellulose I and III lattices, respectively. Resistance to flex abrasion was doubled by pretreatments. Wrinkle recoveries of all controls were equivalent, but tensile recovery differed. BDO reaction enhanced wrinkle recovery of controls but produced the usual losses in tensile properties and resistance to flex abrasion associated with crosslinking reagents. BDO reaction nullified the initial tensile advantage held by CM cotton. Tear strengths of all BDO-treated cottons remained comparable. High dry and high wet recoveries were obtained only when 2% NaOH catalyzed the BDO reaction and were greatest for NH3 cottons. BDO reaction reduced permanent set of all controls and increased tensile recovery primarily by enlarging the delayed recovery. Postmercerization with 23% NaOH adversely affected recovery behavior of all BDO-treated cottons. Nevertheless, wrinkle and tensile recoveries of postmercerized NH3(I) and CM cottons were equivalent. Postmercerization partially restored fabric properties of BDO cottons with cellulose I lattice to those of their respective controls; no change was noted for corresponding products from CM cottons. Because of this, final properties of products from NH3(I) cottons equaled and even exceeded those of comparable CM cottons.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1976.070200718
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  • 3
    Electronic Resource
    Electronic Resource
    Production of penicillin in a fluidized-bed bioreactor: Control of cell growth and penicillin production by phosphate limitation (1988)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 32 (1988), S. 569-573 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260320421
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  • 4
    Electronic Resource
    Electronic Resource
    Enhancement effect of polyethylene glycol on enzymatic synthesis of cephalexin (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 41 (1993), S. 654-658 
    Details
    ISSN: 0006-3592
    Keywords: polyethylene glycol ; hydrophobicity ; enzymatic synthesis ; cephalexin ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In an enzymatic synthesis of cephalexin (CEX) using an acylase from Xanthomonas citri, the effect of polyethylene glycol (PEG) on the synthetic reaction of 7-amino-3-deacetoxycephalosporanic acid (7-ADCA) and D-alpha-phenyl-glycine methyl ester (PGM) to CEX was investigated. The addition of PEG (MW 300-20,000) increased the yield significantly. This yield enhancement effect tended to increase with the increasing molecular weight of PEG. Addition of PEG to the reaction system did not affect both the CEX and PGM hydrolytic reactions. The PEG added to the reaction medium used in these experiments did not depress the water activity significantly, and the product yield improvement could not be explained by the activity alone. The PEG stabilized the enzyme activity to some extent, but this stabilizing effect was only partially attributable to the yield enhancement of CEX. The enhancing effect of PEG on the synthetic yield increased with the increasing PEG molecular weight or the length of the poly(oxy-1,2-ethanediyl) chain, which increases the hydrophobicity of PEG. This finding consequently has led to the conclusion that the PEG structure renders the affinity between enzyme and 7-ADCA, which is a hydrophobic substrate. The microenvironmental hydrophobicity of PEG and its interaction with the hydrophobic substrate was found to be the main reason for the improvement of the CEX yield. In fact, the Michaelis-Menten kinetic constant for 7-ADCA, K7-ADCA in the presence of PEG was smaller than that in the control system (without PEG addition). © 1993 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260410608
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  • 5
    Electronic Resource
    Electronic Resource
    Enhancement effect of water activity on enzymatic synthesis of cephalexin (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 42 (1993), S. 800-806 
    Details
    ISSN: 0006-3592
    Keywords: water activity ; enzyme kinetics ; cephalexin synthesis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The effect of water activity (aw) of the reaction medium on the enzymatic synthesis of cephalexin (CEX) from 7-amino-3-deacetoxycephalosporanic acid (7-ADCA) and D-α-phenylglycine methyl ester (PGM) was investigated using the α-amino acid ester hydrolase enzyme from Xanthomonas citri. It was found that the synthetic activity of the enzyme and the conversion yield were markedly improved when the aw of the reaction medium was lowered to about 0.97. The water activity depressing agents evaluated were glycerol, sucrose, and sorbitol, and the conversion yields were improved up to 170% with 15% glycerol, 230% with 30% sucrose, and 270% with 20% sorbitol, respectively. The extent of favorable effect of aw on the conversion yield was not the same among the aw depressors, probably due to other unknown interactions between the enzyme and depressors. However, optimal aw values corresponding to the maximum conversion yield coincided for all aw depressors used. The conversion yield of CEX showed an increasing trend with increasing aw up to the optimal aw value (0.96-0.97) which corresponds to the maximum conversion yield and a decreasing trend beyond the optimal aw. There appears to be a delicate balance between the hydrolytic reaction of PGM and synthetic reaction of CEX. The increasing aw-[E · PGM] complex and the branched reaction pathway fluxes from [E · PGM] to PG (D-α-phenyl glycine) and CEX are balanced in such a way that the maximum CEX conversion yield is obtained at aw value of 0.96-0.97. The aw depressors stabilized the enzyme somewhat, but this positive effect was considered to be only a minor contribution to the substantial yield enhancement. The aw depressor effect on viscosity and in turn the mass transfer rate limitation was ruled out since the change in conversion due to the viscosity change was found to be insignificant. © 1993 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260420703
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  • 6
    Electronic Resource
    Electronic Resource
    Novel PPV derivatives emitting light over a broad wavelength rangeThis work was supported by the Korea Science and Engineering Foundation. (1997)
    Weinheim : Wiley-Blackwell
    Advanced Materials 9 (1997), S. 551-554 
    Details
    ISSN: 0935-9648
    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
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/adma.19970090706
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  • 7
    Electronic Resource
    Electronic Resource
    Characterization and use of radio frequency plasma-activated natural polymers (1979)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 23 (1979), S. 1987-2003 
    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 group of natural materials having anhydroglucose units linked by glycosidic bonds, as well as other related compounds, were irradiated with plasmas generated by a radio frequency field (13.56 MHz). Reactive sites created were characterized by electron spin resonance, chemiluminescence, infrared, and x-ray photoelectron spectroscopy. The free radicals are related to the number of glycosidic bonds, and their decays result in chemiluminescence. In the absence of moisture and oxygen, however, the radicals are stable. During plasma irradiation, carbonyl groups as well as free radicals are formed on surfaces, and the atom ratio of oxygen to carbon on surfaces increases. Within the reactor, thin films of polymers can be deposited on cotton fabrics by allowing the monomer to enter the reactor above the fabric that is in a horizontal position downstream from the external electrodes.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1979.070230709
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  • 8
    Electronic Resource
    Electronic Resource
    Untersuchungen zum Agglomerationsverhalten von PVC-Dispersionen (1980)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 31 (1980), S. 174-177 
    Details
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Based on known theoretical approaches on the stability and coagulation of disperse systems the agglomeration of an aqueous PVC microsuspension dispersion containing macromolecular dispersing agents has been investigated. In this tenside-stabilized systems different effects of ionogenic and non-ionogenic dispersing agents were established. Further, the behaviour of the agglomerates in this disperse PVC-plastiziser system (DPO) was investigated. Besides the particle size the layer thickness of the macromolecular dispersing agent and the constituents affecting the potential were found to act on the agglomeration and the reversible degradation to particles and thus the flow behaviour. The energy-distance functions of the aqueous and non-aqueous systems can be explained by the DLVO theory.
    Notes: Ausgehend von bekannten theoretischen Ansätzen zur Stabilität und Koagulation disperser Systeme wird die Agglomeration einer wäßrigen PVC-Mikrosuspension-Dispersion mit makromolekularen Dispergatoren untersucht. In diesem tensidstabilisierten System ist eine unterschiedliche Wirkung ionogener und nichtionogener Dispergatoren nachweisbar. Gleichzeitig wird das Verhalten der Agglomerate im dispersen System PVC/Weichmacher (DOP) untersucht. Es kann gezeigt werden, daß neben der Teilchengröße insbesondere die Schichtdicke des makromolekularen Dispergators und potentialbestimmende Inhaltsstoffe die Agglomeration oder den reversiblen Zerfall in die Teilchen und damit das Fließverhalten bestimmen. Mit Hilfe der DLVO-Theorie lassen sich die Energie-Abstands-Funktionen des wäßrigen und nichtwäßrigen Systems erklären.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/actp.1980.010310306
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  • 9
    Electronic Resource
    Electronic Resource
    Theoretische und experimentelle Beiträge zum Fließverhalten von DispersionenVortrag auf dem internationalen Symposium „Polymerdispersionen“, 4. bis 6. September 1978 in Dresden/DDR (1979)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 30 (1979), S. 754-759 
    Details
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: With coarse and fine disperse latex dispersions stabilized by tensides the Simha theory on the viscosity of disperse systems was found to describe satisfactorily the experimental results obtained at low shear rate. Latex dispersions, even with neglegible attraction (model of isolated rigid spheres) show structure viscosity, which is explained by demixing due to flow-dependent displacement of the particles. The demixing can occur within the volume as well as at the boundary of the dispersion.
    Notes: An grob- und feindispersen tensidstabilisierten Latexdispersionen wurde nachgewiesen, daß die von Simha publizierte Theorie zur Viskosität disperser Systeme die experimentellen Ergebnisse bei geringen Schergeschwindigkeiten gut beschreibt. Latexdispersionen, auch mit vernachlässigbaren anziehenden Wechselwirkungen (Modell isolierter harter Kugeln), weisen Strukturviskosität auf. Die Strukturviskosität wurde bei diesen Dispersionen durch Entmischung infolge strömungsbedingter Teilchenverdrängung erklärt, wobei die Entmischung sowohl im Innern der Dispersion als auch am Rand auftreten kann.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/actp.1979.010301206
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