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  • 1
    Electronic Resource
    Electronic Resource
    Poly(vinyl alcohol) as a substrate for indicator immobilization for fiber-optic chemical sensors (1989)
    s.l. : American Chemical Society
    Analytical chemistry 61 (1989), S. 202-205 
    Details
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ac00178a003
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  • 2
    Electronic Resource
    Electronic Resource
    Fundamental studies of grafting reactions in free radical copolymerization. I. A detailed kinetic model for solution polymerization (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2533-2549 
    Details
    ISSN: 0887-624X
    Keywords: free radical ; grafting ; kinetics ; model ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Graft site initiation occurs by primary radical and/ or polymeric radical attack on the back-bone polymer. The controlling mechanism is determined by the structure of the backbone and the activity of the free radicals. The efficiency of incorporating monomer into the graft chains depends upon the graft site initiation mechanism and the mode of polymer chain termination (recombination or disproportionation). A kinetic analysis results a series of uniquely different expressions describing the graft efficiency, φ corresponding to different combinations of graft site initiation and chain termination mechanisms. The dependency of φ upon monomer, initiator, and backbone concentrations is different from case to case. The complete kinetic model is capable of predicting reaction rate, graft efficiency, graft frequency, graft ratio, and molecular weight averages and distributions. Simulations are provided to compare predicted results with experimental data for two different systems which show contrasting mechanisms of graft site initiation and mode of termination. © 1995 John Wiley & Sons, Inc.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1995.080331502
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  • 3
    Electronic Resource
    Electronic Resource
    Fundamental studies of grafting reactions in free radical copolymerization. III. Grafting of styrene, acrylate, and methacrylate monomers onto cis-polybutadiene using benzoyl peroxide initiator in solution polymerization (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2571-2586 
    Details
    ISSN: 0887-624X
    Keywords: grafting ; cis-polybutadiene ; styrene ; acrylate ; methacrylate ; benzoyl peroxide ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Benzoyl peroxide (BPO), due to its higher radical reactivity as compared to AIBN, is known to promote grafting onto cis-polybutadiene. Switching from AIBN to BPO initiator made a dramatic difference in the extent of grafting for styrene and methacrylate monomers, but only a modest difference for acrylate monomer. For styrene and methacrylate monomers, graft site formation is due to BPO initiator radical attack onto the backbone via allylic hydrogen abstraction. Significant levels of grafting are achieved and depend upon the relative concentrations of monomer and backbone polymer but not upon the level of initiator. For acrylic monomer, graft site formation was found to be due to polymer radical attack at the double bond in the backbone. Abstraction of allylic hydrogen also occurs but results in retardation of the overall reaction rate. Graft level was dependent upon initiator and back-bone polymer concentrations but not upon monomer concentration. The effective role of the initiator is only to produce polymer radicals; the BPO has no direct role in the formation of effective graft sites. © 1995 John Wiley & Sons, Inc.
    Additional Material: 31 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1995.080331504
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  • 4
    Electronic Resource
    Electronic Resource
    Fundamental studies of grafting reactions in free radical copolymerization. II. Grafting of styrene, acrylate, and methacrylate monomers onto cis-polybutadiene using AIBN initiator in solution polymerization (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2551-2570 
    Details
    ISSN: 0887-624X
    Keywords: grafting ; cis-polybutadiene ; styrene ; acrylate ; methacrylate ; AIBN ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Grafting can be initiated by primary and/ or polymer radical attack on the backbone polymer and it is well known that AIBN does not readily promote grafting, even when using poly-butadiene. We have studied the grafting of several different monomers onto cis-polybuta-diene using AIBN initiator and find dramatically different results among the monomers. As expected, styrene grafts at very low levels due to the inactivity of the initiator radicals and the polystyryl radicals. Methacrylate monomer grafts at a slightly higher level due to its more reactive polymer radical, while acrylate monomer readily grafts onto the poly-butadiene because polyacrylate radicals are quite reactive. The use of a kinetic model allowed the evaluation of rate coefficients for graft site initiation to be in the relative order of 0.1 : 1.0 : 10.0 (L/mol/s) for styrene:methacrylate:acrylate monomers. The model also pro-vided successful interpretations of the grafting data and its dependence upon the concen-trations of monomer, initiator, and backbone polymer. Due to the relatively higher reactivity of the polyacrylate radicals, the benzene solvent acted as a chain transfer agent in this system. This affected the molecular weight of both free and grafted acrylate polymer and also surpressed the graft level. Polyacrylate radicals attack the cis-polybutadiene backbone by abstracting an allylic hydrogen and also adding across the residual double bond. The latter mechanism is responsible for the majority of the grafting; the hydrogen abstraction leads to relatively inactive radicals which cause a retardation in the overall reaction rate. © 1995 John Wiley & Sons, Inc.
    Additional Material: 32 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1995.080331503
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  • 5
    Electronic Resource
    Electronic Resource
    Fundamental studies of grafting reactions in free radical copolymerization. IV. Grafting of styrene, acrylate, and methacrylate monomers onto vinyl-polybutadiene using benzoyl peroxide and AIBN initiators in solution polymerization. (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2587-2603 
    Details
    ISSN: 0887-624X
    Keywords: grafting ; vinyl-polybutadiene ; styrene ; acrylate ; methacrylate ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Vinyl-1,2 polybutadiene (vinyl-PBD) was used as the backbone polymer for the grafting of styrene, methacrylate, and acrylate monomers using both benzoyl peroxide and AIBN initiators. Radical attack on the backbone can occur through the pendant vinyl group or at the tertiary, allylic hydrogen site. Effective graft sites are formed via double bond addition of either primary (initiator) or polymer radicals. The production of tertiary allylic radicals on the backbone chain also occurs and results in moderate to dramatic reaction rate re-tardation in every monomer system. The type of initiator is only important when the polymer radicals are not very reactive, as in the case of styrene, and to a lesser extent for methacrylate monomer. Graft efficiencies are generally higher when using vinyl-PBD than when using cis-PBD. © 1995 John Wiley & Sons, Inc.
    Additional Material: 41 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1995.080331505
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  • 6
    Electronic Resource
    Electronic Resource
    An advanced computer algorithm for determining morphology development in latex particles (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 58 (1995), S. 1607-1618 
    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 new algorithm is presented for the prediction of equilibrium morphology in latex particles. Thermodynamic equilibrium calculations of the interfacial free energies associated with a large array of possible morphologies serve to create a continuous free-energy surface upon which the preferred morphology is located. When the computations are performed on a 486DX33 PC, the calculations are essentially instantaneous. The graphical output can be refreshed on the monitor screen in less than 2 s. The algorithm is applied to simulate the conversion-dependent morphology for several latex systems composed of polystyrene and poly(methyl methacrylate) and two very different surfactants. © 1995 John Wiley & Sons, Inc.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1995.070580924
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  • 7
    Electronic Resource
    Electronic Resource
    A note on the morphology of composite polymer particles (1991)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 29 (1991), S. 1021-1024 
    Details
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1991.090290812
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  • 8
    Electronic Resource
    Electronic Resource
    A comparison of methods for the estimation of polymer/monomer interaction parameters: The polystyrene/n-butyl methacrylate system methacrylate system (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 52 (1994), S. 1823-1832 
    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: To measure the polymer/monomer interaction parameter as a function of composition, a set of partially cross-linked synthetic latices has been produced by batch and semicontinuous emulsion polymerization. The degrees of cross-linking have been measured by DMA and also predicted by computer simulation based on kinetic data. With equilibrium monomer swelling experiments achieved on films made from these polymers, two curves of the interaction parameter vs. the polymer fraction have been computed. These curves compare favorably with a theoretical model based on a Unifac procedure for the estimation of monomer activity. Two different data bases, liquid-liquid and liquid-vapor equilibria, have been used in the Unifac model. For the polystyrene/n-butyl methacrylate system, a linear relationship found between the interaction parameter and composition is both predicted and measured experimentally. In all cases, this interaction parameter is found to increase with polymer concentration. © 1994 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1994.070521217
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  • 9
    Electronic Resource
    Electronic Resource
    Determination of interfacial tensions for latex particles (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 53 (1994), S. 1469-1476 
    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 possibility of measuring in situ the interfacial tension at the monomer-swollen polymer-water interface of synthetic latices is considered in detail. Experimental measurements of certain liquid or vapor phase properties of the latex can, in principle, yield values of the desired interfacial tension. This technique requires the evaluation and comparison of the Flory-Huggins term and the Morton term of the thermodynamic expression for the chemical potential of the monomer in the latex particle. While each term can be evaluated, it turns out that the relative magnitudes of the two terms are such that unrealistically high precision is required in the experimental measurements for this technique to be useful for obtaining reasonably accurate interfacial tensions. At saturated swelling conditions with highly surface-active emulsifiers (e.g., sodium dodecyl sulfate), the interfacial tension values obtained have a precision of only about ±50%. The reliability of these approximate values degrades rapidly as one moves away from saturation conditions, so as to render in situ experimental techniques inappropriate for gaining accurate knowledge about the surface energy at the latex particle-water interface at any monomer-polymer ratio. © 1994 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1994.070531109
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  • 10
    Electronic Resource
    Electronic Resource
    Morphology development for three-component emulsion polymers: Theory and experiments (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 47 (1993), S. 1277-1294 
    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: Three-component emulsion polymer systems constitute an overall four-component system from a morphological viewpoint. The aqueous phase is always the continuous phase within which 22 distinct and thermodynamically stable particle morphologies may exist. Six uniquely different categories of particles compose this morphological menu and may be identified as core-shell-shell, hemicore, hemishell, trisectional, “snowman,” and cored hemisphere. Extension of previously published free-energy thermodynamic analyses of two component emulsion polymers has resulted in the ability to predict the most likely equilibrium morphology to be found for three-component particles. Predictions have been carried out for each possible three-component combination of poly(methyl methacrylate), polystyrene, poly(dimethyl siloxane), and polycarbonate. The results show that in nearly every instance two or three different morphologies are computed to possess nearly equivalent free energies, whereas all other possibilities would result in much higher free energies. This indicates that more precise knowledge of all interfacial tensions is required when considering three-component systems than was found to be generally needed for two-component systems. Experiments were carried out for each polymer combination using a very surface-active emulsifier (sodium lauryl sulfate) and, separately, a weakly surface-active emulsifier (natural pectin). For this choice of polymers and emulsifiers, only three of the six unique morphological categories were found experimentally. In all cases, the thermodynamic analysis predicted the experimentally determined morphology to possess the lowest or next to lowest free energy. © 1993 John Wiley & Sons, Inc.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1993.070470716
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