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  • 1
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Journal of Photochemistry 17 (1981), S. 118 
    ISSN: 0047-2670
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 679-689 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mechanism of flame retardant (FR) action of red phosphorus in polyacrylonitrile combustion was investigated by thermogravimetry, flash-pyrolysis GC-MS, and combustion methods. Red phosphorus was found to increase the thermal stability in air of polyacrylonitrile and to induce a char residue increment on this substrate. Both these effects disappeared when pyrolysis was carried out under nitrogen flow. Flash-pyrolysis GC-MS experiments showed that red phosphorus does not alter the pyrolysis product distribution of polyacrylonitrile, which implies that there is no specific interaction between polyacrylonitrile and red phosphorus. These data also showed that polymeric red phosphorus decomposes to volatile white phosphorus (P4) during pyrolysis. These observations allow us to propose a simple model for the mechanism of FR action of red phosphorus on polyacry-lonitrile at the molecular level. Combustion data for polyacrylonitrile-red phosphorus mixtures are in agreement with the proposed mechanism of FR action.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 3
    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: Photochemically induced grafting (1) and graft polymerization (2) from N,N-dimethylformamide solutions of four acryloxy-substituted aromatic diazenes, chosen as model molecules of acryloxy azo dyes, were investigated kinetically at 25°C onto polypropylene, polycaprolactam, and poly(ethylene terephtalate) films, by polychromatic irradiations. Quantum efficiencies at zero concentration of dyes and lifetimes of excited states for processes (1) and (2) were evaluated from experimental data by Stern-Volmer plots. The surface density of grafted molecules at the end of process (1) was not affected by the concentration of dyes in solution, but varied sensibly with the chemical nature of polymers and dyes. The relevant parameters are discussed on the basis of the proposed mechanism.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 4
    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: Photochemically induced grafting and graft polymerization of 4-(N-ethyl, N-2-acryloxyethyl) amino, 4′-nitro, azobenzene(I), brought into contact with polyamide and polypropylene fibers by evaporation of solvent from toluene solutions, has been investigated kinetically at 45°C. Two constant-rate periods were observed. The first one was interpreted on the basis of an autosensitized grafting mechanism of monomeric or oligomeric species of (I), photochemically initiated by hydrogen abstraction from the polymer surface. This first step occurred at a rate dependent on the chemical nature of the substrate being faster for polyamide than for polypropylene by a factor of about 1.25; it was followed by a brief induction period, after which a transient autoacceleration led to a second constant rate process, independent of the substrate. This latter step was explained as an autosensitized photochemically induced graft polymerization of (I) on the first grafted layer.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The thermal behaviour of copolymers of acrylonitrile containing up to 15 wt.-% of methyl acrylate (MA), methyl methacrylate (MMA), vinyl acetate (VA), and vinyl bromide (VB) units, was investigated by gradually increasing the temperature of a polymer sample placed in the ion source of a mass spectrometer (MS). The resulting pyrolytic processes (time-temperature resolved) were analyzed by detecting the volatile decomposition products formed. Several decomposition processes were ascertained. Bromine derivatives evolution from the VB copolymer chain occurs already at 160-200°C. The thermal decomposition of the pendant ester groups in the MA and MMA copolymers occurs in the temperature range of 200-260 °C. Typical polyacrylonitrile (PAN) decomposition fragments were detected in the 240-300 °C range in all the copolymers investigated. Acetic acid units are evolved from the VA copolymer simultaneously to the PAN thermal fragments. Heterocyclic compounds originated from the ladder structures appear beyond 300°C.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The thermal behaviour of copolymers of acrylonitrile containing vinylidene chloride (VC2), 1-bromo-1-chloroethylene (VCB), vinyl bromide (VB) units and Sb2O3, was investigated by gradually increasing the temperature of a polymer sample placed in the ion source of a mass spectrometer (MS). The resulting pyrolytic processes (time-temperature resolved) were analyzed by detecting the volatile decomposition products formed. Sb-halogenated species were detected in the mass spectra of the thermal decomposition products of the copolymers, and their presence is interpreted as the result of antimony-halogen hydracids interactions during the pyrolysis.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 182 (1981), S. 1301-1306 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Elemental red phosphorus was found to be an efficient flame retardant for poly(acrylonitrile) homopolymer (PAN) and, to a lesser extent, also for a modified acrylic resin containing 36 wt.-% of vinylidene chloride (VC2) as comonomer. The data collected show that condensedphase and gas-phase mechanisms are both responsible for the flame inhibition effect of red phosphorus on PAN. On the contrary, a gas-phase mechanism seems to be responsible for the flame inhibition effect of red phosphorus on the AN-VC2 copolymer. Flash-pyrolysis GC data, with pyrolysis products MS identification, are reported for both polymers studied.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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