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  • 1
    Electronic Resource
    Electronic Resource
    Transcrystallinity in injection molded polypropylene glass fibre composites (1983)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 113 (1983), S. 113-120 
    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 das Vorkommen von Transkristallinität in Polypropylen bei Anwesenheit von Glasfasern unter Spannung untersucht. Das Experiment wurde an einem Heiztisch-Polarisationsmikroskop durchgeführt. Dabei zeigte sich, daß leichte mechanische Spannung an den Faser-Polymer-Grenzflächen zu Oberflächennukleierung und Wachstum von transkristallinen Bereichen führt. Gemische von Polypropylen mit verschiedenen Konzentrationen von Glasfasern wurden durch Spritzgießen hergestellt. Die beobachteten transkristallinen Bereiche der Spritzgußproben wurden auf genügende innere Spannungen zurückgeführt. Ferner zeigte sich, daß die Zunahme der Faserkonzentration die Transkristallinität erhöht. Das weist darauf hin, daß die inneren Spannungen mit zunehmendem Faseranteil angestiegen sind.
    Notes: The occurrence of transcrystallinity in polypropylene in the presence of glass fibres under stress was studied. An experiment was designed on a hot-stage polarizing microscope in which it was found that slight mechanical stress at the fibre polymer interface gives rise to surface nucleation and growth of transcrystalline regions. Composites of polypropylene with various concentrations of glass fibres were prepared by injection molding. The observed transcrystalline regions in the injection molded samples were attributed to the availability of sufficient inherent internal stresses. Moreover, an increase in fibre concentration was found to enhance transcrystallinity. This indicated that the internal stresses were increased with increasing fibre population.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1983.051130111
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  • 2
    Electronic Resource
    Electronic Resource
    Fibers from blends of PBT and thermotropic liquid crystalline copolyester (1995)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 46 (1995), S. 178-182 
    Details
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Blends of poly(ethylene terephthalate-co-p-oxybenzoate), PET/PHB, with poly(butylene terephthtalate), PBT, have been studied in the form of as-spun and drawn fibers. DSC melting and crystallization studies of blend fibers show a single melting endotherm, corresponding to PBT crystallites and a decrease in the crystallization of PBT by the addition of LCP in the matrix. X-ray diffraction patterns of the blends exhibit mainly all the reflections of the homopolymer component (PBT). However, the diffused meridional reflections in the blend fibers show that the crystal structure of the matrix is affected by the addition of LCP and there is possible formation of LCP oriented domains. SEM studies of drawn blend fibers show that the blends up to 10 wt.% LCP content contain the LCP domains in the size range of 0.1--0.3 μm and are well distributed in the PBT matrix. Mechanical properties of drawn PBT/LCP blend fibers show an increase in modulus with the increase in LCP content. Values of the modulus are predicted from composite theory by assuming the blend system to consist of LCP domains dispersed in PBT matrix.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/actp.1995.010460213
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  • 3
    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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  • 4
    Electronic Resource
    Electronic Resource
    A study on blends of different molecular weights of polypropylene (1986)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 31 (1986), S. 2145-2155 
    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: Blends of small percentage of plastic grade polypropylene with fiber grade polypropylene are studied in unoriented and oriented states. A 3% blend sample has a higher spherulitic growth rate, and improved mechanical behavior in drawn fiber state as compared to the parent sample. These changes are related to the presence of bimodal and trimodal crystal texture of polypropylene in the blend, respectively. At a higher blend percent, specifically at 10 and 15%, the mechanical properties of the drawn fiber are inferior and these are related to partial phase segregation of the components.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1986.070310718
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  • 5
    Electronic Resource
    Electronic Resource
    Fibers from poly(ethylene terephthalate) and poly(butylene terephthalate) blends I. Mechanical behavior (1987)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 33 (1987), S. 759-768 
    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: Fibers prepared from poly(ethylene terephthalate) (PET) and poly(butylene terephthalate) (PBT) blends show a sharp decrease in tensile strength and modulus when blends are on the verge of phase segregation. The modulus values differ for homopolymers for their differences in chain configuration and methylene groups and that of the blends are in proportion. The experimental strength values are higher than the predicted values according to Paul's model for incompatible polymers. At 90/10 PET/PBT blend, the modulus is high, which may be a relative factor to the smaller crystal size of the components.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1987.070330306
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  • 6
    Electronic Resource
    Electronic Resource
    A study on blends of nylon-6 and nylon-66 (1986)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 31 (1986), S. 747-762 
    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: Blending of nylon-6 and nylon-66 was carried out by coextrusion in the whole range of compositions with particular emphasis on small amounts of one polymer in the other. Most significant improvement in properties is achieved at low blend compositions in which the minor component remains amorphous while severely affecting the crystallization behavior of the major component. The nylon-6-rich blends crystallize predominantly in the γ-crystalline form, whereas the nylon-66-rich blends exhibit low crystallinity. Because of this property, the blends are more easily drawable, giving rise to a more highly oriented structure with improved tensile properties and uniformity. High tenacity and modulus are observed in drawn blends containing 70% nylon 6 and 30% nylon-66.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1986.070310301
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  • 7
    Electronic Resource
    Electronic Resource
    Tie chains and modulus of nylon 6 fibers (1982)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 27 (1982), S. 3211-3218 
    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 large number of nylon 6 fiber samples with varying internal structure were obtained by changing draw ratios, drawing temperature, and quenching immediately after drawing. Modulus of these samples is analyzed by Takayanagi model and fraction of tie chains is obtained. It is observed that the modulus of these samples is directly proportional to the fraction of tie chains.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1982.070270903
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  • 8
    Electronic Resource
    Electronic Resource
    Fibers spun from blends of different molecular weights of polypropylene (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 43 (1991), S. 49-56 
    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: Fibers spun from blends of small percentage of plastic grade polypropylene (HMPP) with fiber grade polypropylene (PP) are studied for drawing behavior. A factorial design of experiment is used for a two-stage drawing process with variables, such as percent of HMPP component, first stage draw ratio and temperature, and second stage temperature. Optimization is carried out for breaking stress and modulus of drawn filaments. Breaking stress of up to 0.74 GPa and initial modulus of 7.34 GPa is possible by such an optimization process. These properties are observed for 6% HMPP blend composition. Heat setting of drawn filaments show little changes up to 140°C heat-setting temperature. Large scale structural changes with rapid drop in mechanical properties is observed for 150-160°C heat-set samples.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1991.070430107
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  • 9
    Electronic Resource
    Electronic Resource
    Crystallization behavior of high-density polyethylene/linear low-density polyethylene blend (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 44 (1992), S. 719-726 
    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: Binary blend of high-density polyethylene (HDPE) and linear low-density polyethylene (LLDPE), prepared by melt mixing in an extruder, in the entire range of blending ratio, is studied for crystallization behavior by differential scanning calorimetry (DSC) and X-ray diffraction measurements. Cocrystallization was evident in the entire range of blend composition, from the single-peak character in both DSC crystallization exotherms and meltingendotherms and the X-ray diffraction peaks. A detailed analysis of DSC crystallization exotherms revealed a systematic effect of the addition of LLDPE on nucleation rate and the subsequently developed crystalline morphology, which could be distinguished in the three regions of blending ratio, viz, the “HDPE-rich blend,” “LLDPE-rich blend,” and the “middle range from 30-70% LLDPE content.” Variations in crystallinity, crystallite size, and d spacing are discussed in terms of differences in molecular structure of the components.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1992.070440418
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  • 10
    Electronic Resource
    Electronic Resource
    Mechanical properties and morphology of high-density polyethylene/linear low-density polyethylene blend (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 46 (1992), S. 99-108 
    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 binary blend of high-density polyethylene (HDPE) and linear low-density polyethylene (LLDPE) in the range of composition from 100% HDPE to 100% LLDPE has been investigated for tensile and flexural properties and the morphology in the deformed state on tensile fracture. Tensile properties (initial modulus, yield stress, and elongation-at-yield, ultimate tensile strength and elongation-at-break, and work of yield and work of rupture) and flexural properties (flexural modulus and flexural yield stress) are studied as a function of blend composition. Behavior, in terms of these properties, is distinguishable in three zones of blend composition, viz. (i) HDPE-rich blend, (ii) LLDPE-rich blend, and (iii) the middle zone. In zones (i) and (ii), the variations of these properties are more or less linear, whereas in the middle region [i.e., zone (iii)], there is a reversal of trends in variation or sometimes a behavior opposite to the expected one. The results are explained on the basis of the effects of cocrystallization and the presence of octene-containing segments in the amorphous phase. Scanning electron micrographs of the tensile fracture surfaces are presented to illustrate the occurrence of transverse bands interconnecting the fibrils.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1992.070460110
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