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  • 1975-1979  (23)
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  • 11
    Electronic Resource
    Electronic Resource
    Thermal degradation of poly(vinyl chloride) in alkyl maleates (1978)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 66 (1978), S. 105-112 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Es wurde der thermische Abbau von Polyvinylchlorid uner Stickstoff in Diäthyl-Dibuyl- und Dioctylmaleat zwischen 160 und 210°C untersucht. Die Dehydrochlorierungsgeschwindigkeit ist in Dibutylmaleat am höchsten und in Dioctylmaleat am niedrigsten. Die aktivierungsenergie liegt bei 83,6, 122,7 und 150,5 kJ mol-1 für Diäthyl-Dibuyl- und Dioctylmaleat. Die Dehydrochlorierungsgeschwindigkeit und die Aktivierungsenergien liegen in Alkylmaleaten höher als in áthylbenzoat. In alkylmaleaten sind die Absorptionen im sichtbaren UV erheblich verringert.
    Notes: The thermal degradation of poly(vinyl chloride) has been investigated in diethyl, dibutyl and dioctyl maleate under nitrogen from 160°C to 210°C. The rate of dehydrochlorination was highest in dibutyl maleate and lowest in dioctyl maleate. The apparent activation energy calculated from the average value of the rate constant at each temperature for diethyl, dibutyl and dioctyl maleate was found to be 83.6 kJ mole-1, 112.7 kJ mole-1, and 150.5 kJ mole-1, respectively. The rates of dehydrochlorination and the activation energy observed in alkyl maleates are higher than those observed in ethyl benzoate. In the visible range spectra the absorption at higher wavelengths is considerably reduced in alkyl maleates.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1978.050660109
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  • 12
    Electronic Resource
    Electronic Resource
    Thermal degradation of poly(vinyl chloride) in presence of additives, part II. Changes in absorption spectra (1979)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 78 (1979), S. 181-193 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Das Absorptionsspektrum von in Äthylbenzoat bei 200°C in Anwesenheit von Maleinsäureanhydrid (MA), Benzochinon (BQ) und Anthrachinon (AQ) abgebautem PVC wurde untersucht. Die Polyensequenzlängenverteilung wurde berechnet und festgestellt, daß die Bildung von Polyenen mit 6 konjugierten Doppelbindungen durch MA, nicht hingegen durch BQ und AQ reduziert wird. BQ und AQ verringern aber die Bildung von längeren Polyenen (n=8). Das Alterungsverhalten der abgebauten Polymerproben wird ebenfalls untersucht.
    Notes: Electronic absorption spectra of PVC degraded in ethyl benzoate at 200°C in presence of maleic anhydride (MA), benzoquinone (BQ) und anthraquinone (AQ), were studied. The distribution of polyene sequence length was calculated. It was observed that the rate of formation of polyenes having 6 conjugated double bonds was reduced in presence of MA. In case of BQ and AQ, no such inhibiting effect was observed. However, formation of polyenes having a higher number of double bonds (i. e. n=8) was reduced in the presence of these additives. The ageing behaviour of the degraded polymer samples was also investigated.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1979.050780113
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  • 13
    Electronic Resource
    Electronic Resource
    Polyester fibres with improved dye uptake (1979)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 82 (1979), S. 63-78 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Es wurden Polyetherterephthalate (PET), die Ethersegmente enthalten, durch Schmelzkondensation unter Verwendung von Dimethylterephthalat (DMT) und unterschiedlichen Mengen von Ethylenglykol (EG) und Polyethylenglykol (PEG) als Ausgangsmonomere hergestellt.Die Charakterisierung der Polymeren erfolgte durch Messungen der Viskosität und der dynamischen Thermogravimetrie in Luft. Der Schmelzpunkt erniedrigte sich von 258°C bis 244°C mit zunehmendem Anteil von Polyethersegmenten in der Polymerkette.Diese Polymeren wurden unter Verwendung der Schmelzspinntechnik zu Fasern versponnen. Die Fasern wurden bis zu unterschiedlichen Verstreckungsverhältnissen verstreckt und dann getempert. Mit der Zunahme der Polyethersegmente im Copolymeren, wurde eine Erniedrigung von ReiRfestigkeit und Anfangsmoduln festgestellt, wahrend sich die prozentuale Dehnung erhohte. Eine optimale Festigkeit wurde mit BL 3 Fasern erzielt, und eine weitere Erhohung von PEG (BL 4) beeinfluRt die Festigkeit und Anfangsmoduln nicht mehr.Die Farbaufnahme und Wasserdampfsorption der Copolyester war deutlich erhoht, verglichen mit PET.Die Kristallinitat und Orientierung wurde durch Rontgenbeugung bestimmt. In den zug- und hitzebehandelten Fasern erniedrigte sich die Dichte mit der Erhohung des PEG-Anteils, dagegen war erwartungsgemaR die Dichte in BL 4 hoher als in PET.
    Notes: Poly(ethylene terephthalate) (PET) having ether segments have been prepared by melt condensation by taking dimethyl terephthalate (DMT) and different quantities of ethylene glycol (EG) and polyethyl'ene glycol (PEG) in the initial monomer feed.The polymers were characterized by intrinsic viscosity measurements. The relative thermal stability of the polymers was evaluated by dynamic thermogravimetry in air. The melting point was found to decrease from 258-244°C with increase of polyethylene oxide segments in the polymer backbone.These polymers were spun into fibres by using melt spinning technique. The fibres were drawn to different draw ratios and then heat-set. With the increase of the mole percentage of polyether segments in the copolymers, a decrease in tensile strength and initial modulus of the fibres was observed while percentage elongation increased. An optimum tenacity was obtained with BL 3 fibres, and further increase of PEG (BL 4) did not affect the tenacity of initial modulus. The dye uptake and moisture regain in copolyesters was greatly enhanced compared to PET. The crystallinity and orientation of fibres was studied by X-ray diffraction pattern. In the drawn and heat set fibres, the density decreased on increasing the PEG content except in BL 4 where the density was higher than in PET.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1979.050820106
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  • 14
    Electronic Resource
    Electronic Resource
    Thermal analysis of poly(1,3,4-oxadiazole-2,5 diyl-1,2-ethenediyl) and poly(1,4-phenylene-1,3,4-oxadiazole-2,5 diyl-1,2 ethendiyl) (1975)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 19 (1975), S. 2869-2878 
    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: Poly(1,3,4-oxadiazole-2,5-diyl-1,2-ethendiyl) and poly(1,4-phenylene-1,3,4-oxadiazole-2,5 diyl-1,2-ethenediyl) have been prepared by condensation polymerization using fuming sulfuric acid and different quantities of terephthalic acid (T), fumaric acid (F), and hydrazine sulfate (HS). Homopolymers of F and T and various copolymers of F:T have been prepared. The polymer structure was investigated by IR and visible-range spectra and elemental analysis. The existence of poly(1,3,4-oxadiazole-diylphenylene) and poly(hydrazoterephthaloyl) structures was revealed by these studies. These polymers were thermally stable, and most of them did not show a weight loss below 350°C. The relative thermal stabilities of the various polymers have been evaluated by “integral procedural decomposition temperature” and activation energy measurements.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1975.070191022
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  • 15
    Electronic Resource
    Electronic Resource
    Preparation and properties of polyimide fibers (1979)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 24 (1979), S. 1061-1072 
    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: Polyimides were synthesized from 4,4′-diamino diphenyl methane and pyromellitic dianhydride using low-temperature solution polycondensation. Solutions of these polyamic acids in dimethyl-formamide (DMF) were spun into fibers by the wet spinning technique using a mixture of DMF and water as coagulants. Various spinning parameters such as dope concentration, bath composition, and jet stretch were standardized to get polyimide fibers with optimum properties. It was observed that fibers spun at higher jet stretch did not cyclize satisfactorily. Higher dope concentrations gave fibers with better properties. Cyclodehydrated fibers were hot-drawn at 300°C. Fibers with a tenacity of 380 mN/tex, an extension at break of 10%, and initial modulus of 4060 mN/tex were obtained. Mechanical properties of fibers at elevated temperatures, i.e., 100 and 200°C were also measured. Heat aging at 100, 200, and 300°C was carried out for 10 hr. This resulted in an increase in the initial modulus of fibers. However, a 28% decrease in tenacity was observed when the fibers were heat-aged at 300°C. The dynamic thermogravimetry in air showed that fibers were stable up to 400°C. The activation energy of decomposition, calculated from these thermograms in the temperature range 540-610°C was 101 kJ/mole.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1979.070240419
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  • 16
    Electronic Resource
    Electronic Resource
    Poly(ethenyl-1,3,4-oxadiazole-2,5-diyl-1,4-phenylene). Electrical properties and phase transition studies (1976)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 20 (1976), S. 1813-1822 
    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 phase diagrams of the ternary system poly(ethenyl-1,3,4-oxadiazole-2,5-diyl-1,4 phenylene), sulfuric acid, and water indicated that the increase of the ethenyl residue in the copolymers increased the solubility in the acid. The critical point of separation in sulfuric acid was determined, and it decreased from 74% to 60.5% as the ethenyl ratio of copolymers was increased. The electrical properties in the temperature range of 0-90°C at a fixed frequency of 1592 Hz were also investigated. The tan δ values increased with increase in temperature and passed through a maximum. The temperature of this maximum varied with the nature of the copolymer. The observed increase in the dielectric constant with temperature may be due to increased segmental motion in the amorphous region of the polymers.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1976.070200711
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  • 17
    Electronic Resource
    Electronic Resource
    Irradiation of poly(vinyl alcohol) fibers in the presence of chloroform and carbon tetrachloride (1977)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 21 (1977), S. 2913-2920 
    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: Radiolysis of poly(vinyl alcohol) fibers (PVA) in the presence of chloroform and carbon tetrachloride was investigated. Decrease in intrinsic viscosity was observed at lower dosages (up to 2.3 megarads); and above this, an increase was noted. The blank samples irradiated under similar conditions showed a continuous decrease in intrinsic viscosity. A discoloration in the samples irradiated in the presence of CCl4 and CHCl3 was also observed. It is attributed to double bond formation in the backbone. A marginal decrease in the tensile strength of the irradiated fibers was observed. However, the surface characteristics of the fibers did not change on irradiation. The thermogravimetric analysis revealed a better heat resistance in irradiated fibers.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1977.070211107
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  • 18
    Electronic Resource
    Electronic Resource
    Polyimide fibers: Structure and morphology (1979)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 23 (1979), S. 3541-3552 
    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: Polyimide fibers were prepared by wet spinning of poly(p,p′ -diaminodiphenylmethanepyro-mellitamic acid). Density measurements and x-ray diffraction studies were carried out to study the structure of the resultant polyimide fibers. Polyamic acid as well as undrawn polyimide fibers were essentially amorphous with two amorphous haloes. Hot drawing of the fibers at 300°C resulted in increase in crystallinity, and a simultaneous decrease in density also took place. X-ray data revealed that meridional reflections correspond to the repeat unit length in the fiber. Scanning electron micrography studies indicated that polyamic acid fibers prepared by a wet-spinning technique developed voids during spinning which increased on cyclodehydration to the polyimide state. Hot drawing of fibers resulted in enlargement of these voids. However, a highly fibrillated structure was developed during drawing which could account for the strength of the fibers.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1979.070231210
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  • 19
    Electronic Resource
    Electronic Resource
    Poly(1,3,4-oxadiazoles). Effect of structure on polymer properties (1978)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 22 (1978), S. 411-418 
    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: Poly(1,3,4-oxadiazole-2,5-diylvinylene) and poly(1,4-phenylene-1,3,4-oxadiazole-2,5-diylvinylene) were prepared by polymerizing different quantities of terephthalic acid (T), maleic acid (M), and hydrazine sulfate (HS) in the presence of fuming sulfuric acid. Homopolymers of M and T and various copolymers of M:T were prepared. The polymers were characterized by viscosity, IR, UV, and elemental analysis. Their solubility in different solvents was investigated. The relative thermal stability of the polymers was evaluated by TGA and DTA.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1978.070220210
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  • 20
    Electronic Resource
    Electronic Resource
    Copolymers of 2-hydroxyethyl methacrylate and alkyl acrylates: Studies of molecular weight distribution and thermal behavior (1979)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 17 (1979), S. 3279-3289 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several copolymers of 2-hydroxyethyl methacrylate (HEMA) with methyl acrylate (MA), ethyl acrylate (EA), n-butyl acrylate (BA), and methyl methacrylate (MMA) were prepared at 70°C in nitrogen atmosphere using 0.2% (w/v) benzoyl peroxide as initiator. The copolymer composition was evaluated by estimation of hydroxyl group in the copolymers. Intrinsic viscosity of HEMA-EA, HEMA-BA, and HEMA-MMA copolymers was determined at 35°C in dimethyl formamide. Molecular weight distribution of copolymer samples was evaluated by gel permeation chromatography. Thermal behavior of the copolymers was investigated by dynamic thermogravimetry. Thermal stability decreased on increasing HEMA content in MA, EA, and BA copolymers. However, a reverse trend was observed in HEMA-MMA copolymers.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1979.170171017
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