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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Colloid & polymer science 263 (1985), S. 730-737 
    ISSN: 1435-1536
    Keywords: Polypropylene fibre ; crystallinity ; morphology ; melting behaviour ; mechanical properties
    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 Crystallinity measurements were carried out with the help of X-ray diffraction, differential scanning calorimetry (DSC) and density measurements. The results of this study provide a better understanding of the morphology and complex thermal behaviour of polypropylene fibres. Crystallinity studies show that the crystallinity of PP fibres when measured by X-ray and DSC methods as a function of draw-ratios increases with increasing draw-ratios while the crystallinity of the same samples as derived by density measurements shows an inverse trend. These discrepancies are accounted for by the formation of microvoids within the polypropylene fibres due to drawing. In the DSC scan two endothermic peaks were found to occur in some of the samples. This is explained by the presence of two morphological forms i. e. lamellar and fibrillar morphology in the same sample. The crystallinity values obtained from different methods are correlated with mechanical properties, such as tenacity and elongations.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 54 (1992), S. 334-339 
    ISSN: 1432-0630
    Keywords: 07.20.−n ; 0.7.62+s ; 44.50.+f
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract For the measurement of the thermal capacity and the thermal conductivity of films, the thermal excitation of the sample is commonly performed by the absorption of light. This results in a spatial and temporal temperature distribution within the film. With a variety of methods static or dynamic temperature recordings are performed. Two problems with these methods are discussed, the calculation of the temperature distribution in the film and the measurement of the mean surface temperature of the film. An analytical solution of the heat conduction problem for a cylindrical geometry with any radial distribution of the absorbed light is given. Resistive bolometers are introduced for the measurement of the mean surface temperature of the film within a circular area. Experiments with a 25 μm thick PVDF film give excellent agreement with the theoretical calculations within the modulation frequency range 10−3 Hz to 103 Hz, thus allowing a determination of various thermal parameters of the investigated film.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1435-1536
    Keywords: Polypropylene fibre ; Morphology ; Tensile properties
    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 The present paper reports an investigation in which X-ray diffraction (WAXS and SAXS) patterns are applied to obtain qualitative information regarding supermolecular structure of drawn und undrawn samples of polypropylene fibres. The tensile properties, increase of long period, formation of microvoids and lamellar orientation upon drawing of the fibre have been brought into focus.
    Type of Medium: Electronic Resource
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