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  • Polymer and Materials Science  (31)
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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 17 (1973), S. 319-331 
    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: Ethylene-propylene (EP) copolymers were fractionated according to chemical composition, molecular weight, or monomer sequence length, which are fundamental distribution factors. Cloud points of polyethylene (PE), polypropylene (PP), and EP copolymer were determined prior to the fractionation. From the results, it was estimated that xylene-butyl cellosolve and tetralin-ethyl carbitol systems were suitable for the fractionations according to chemical composition and molecular weight, respectively. EP random-type copolymers were fractionated using a xylene-butyl cellosolve system. Separations according to chemical composition were obtained as expected. Then, the above polymer fractions were further fractionated in a tetralin-ethyl carbitol system. and the dependence on molecular weight was observed fairly well. Furthermore, fractionation according to monomer sequence length was satisfactorily achieved by solvent extraction using ethyl ether, n-hexane, cyclohexane, and n-heptane. Therefore, it is concluded that the more detailed characterizations of EP copolymers are made possible by a combination of these techniques.
    Additional Material: 9 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 16 (1972), S. 2257-2268 
    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 effects of the combination of solvent and nonsolvent on the column fractionation of polypropylene were investigated. Decalin, kerosene, and α-chloronaphthalene were employed as the solvents, whereas ethyl and butyl carbitol were employed as the nonsolvents. It was found that the molecular weight distribution of the fractions was not very significantly affected by the combination of solvent and nonsolvent. By applying Caplan's theory, namely, that M̄-1/2 is a linear function of the weight fraction of solvent contained in the eluent (where M is the average molecular weight of a fraction), we concluded that to conduct a good fractionation both the solvent and the nonsolvent should be poorer solvents for the polymer.
    Additional Material: 10 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 17 (1973), S. 2435-2441 
    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 following well-known equation permits the ready determination of Mn from a single osmotic pressure measurement at a known concentration, if the second virial coefficient is previously given: \documentclass{article}\pagestyle{empty}\begin{document}$ \left( {{\pi \mathord{\left/ {\vphantom {\pi C}} \right. \kern-\nulldelimiterspace} C}} \right)^{{1 \mathord{\left/ {\vphantom {1 2}} \right. \kern-\nulldelimiterspace} 2}} = \left( {{{RT} \mathord{\left/ {\vphantom {{RT} {\bar M_n }}} \right. \kern-\nulldelimiterspace} {\bar M_n }}} \right)^{{1 \mathord{\left/ {\vphantom {1 2}} \right. \kern-\nulldelimiterspace} 2}} \left( {1 + {{\Gamma _2 C} \mathord{\left/ {\vphantom {{\Gamma _2 C} 2}} \right. \kern-\nulldelimiterspace} 2}} \right). $\end{document} On this basis, the one-point method was investigated to determine the number-average molecular weight. It was found that this method was applicable to commercial polymers. However, in this application, the dependence of Γ2 on molecular weight distribution has to be kept in mind.
    Additional Material: 8 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 20 (1976), S. 2101-2110 
    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 effects of variables on treatment of the gel permeation chromatogram are reported. Variables investigated include (1) the molecular weight distribution of polymers for preparing the calibration curve, i.e., the logarithm molecular weight-elution count relationship, (2) nonlinearity of the calibration curve, and (3) fluctuation of the baseline. The deviation of the calibration curve prepared by the polymer having broad molecular weight distribution was evaluated in detail by assuming log-normal distribution function for the distribution. The polymer having a D value less than 1.3 was recommended for this purpose. Generally, the shape of the chromatogram is fairly different from that of the true molecular weight distribution curve when the calibration curve is not linear over the entire range of interest. By fitting polynomials to the calibration curve, the chromatogram was sufficiently converted to the molecular weight distribution curve. The apparent difference between them was removed. Slight deviation of the baseline from the true one gave rise to obvious error in the calculated molecular weight and its distribution, especially for the sample having a broad distribution.
    Additional Material: 8 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 3141-3149 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Successful chromatograms were obtained for trifluoroacetylated nylon 12 (N-TFA-N) in gel permeation chromatography (GPC) with dichloromethane as eluent. It was confirmed that the method of universal calibration was applicable for N-TFA-N and polystyrene. The average molecular weights of nylon 12 were obtained from the chromatogram of N-TFA-N by use of the calibration curve for polystyrene. The stability of N-TFA-N in solution was examined from various angles. Satisfactory results are obtained, if the sample solution is measured within 48 h after preparation.
    Additional Material: 6 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 24 (1986), S. 109-118 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Molecular weight distribution of Nylon 12 was determined with hexafluoroisopropanol/toluene mixture as eluent by gel permeation chromatography. Calibration curve for Nylon 12 was easily obtained from that of polystyrene because the method of universal calibration was applicable among these polymers. The molecular weight distributions of Nylon 12 were always broader than expected by the theory of polymerization, i.e., most probable distribution. This result was not caused by broadening effect in gel permeation chromatography, but by polymerization itself.
    Additional Material: 6 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 44 (1992), S. 1869-1871 
    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
    Additional Material: 1 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 53 (1994), S. 1663-1668 
    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: We tried to correlate the polymer constitutes with the peak areas under tan δ-temperature curves, which are abbreviated as TA (loss tangent area) hereafter. TAs for homopolymers were obtained as the summation of ratio of contributions for functional groups in addition to the constant. TAs for semicrystalline polymers decreased with increase of the degree of crystallinity. Therefore, TAs for semicrystalline polymers were estimated from the ratio of the contribution of functional groups and crystallinity. TAs for copolymers were obtained by adopting the idea of mole ratio. Thus, the predicted values were fairly good in agreement with the measured ones for almost all kinds of linear polymers adapted in this study. © 1994 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 40 (1990), S. 1519-1527 
    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: Sufficient fractionation was attained for polyacetal copolymers by the column elution method. The characteristics of molecular weight, composition, and sequence length of the original copolymers were evaluated through the analyses of fractions by 1H-NMR, GPC, and DSC. Comonomer content in polymer fractions decreased with the increase of molecular weight in any samples, and the copolymer prepared by gas-phase polymerization showed broad compositional distribution as compared with that by solution polymerization.
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 48 (1993), S. 1739-1748 
    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: Aromatic polyimides have many advantages such as low thermal expansion coefficient, good electrical insulation, and self-extinguishing properties. We tried to use polyimide film for honeycomb structure. Polymide honeycomb core and sandwich panel were prepared from polyimide film, i.e., UPILEX R, and adhesive by the expansion method. Mechanical properties, i.e., compressive, crushed, shear, and flexural strengths, were evaluated for this core and panel. Compressive and crushed properties increased largely with the density of the honeycomb, whereas shear and midspan flexural properties did not vary so much with the density, because these failures occured in the adhered interface. Strong adhesion is required for improving the latter properties. © 1993 John Wiley & Sons, Inc.
    Additional Material: 15 Ill.
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