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  • 1
    Electronic Resource
    Electronic Resource
    The crystal structure of polycaproamide: Nylon 6 (1955)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 17 (1955), S. 159-177 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The crystal structure of nylon 6 (—NH (CH2)5CO—)p has been determined by interpretation of the x-ray diffraction patterns given by drawn, rolled fibers. The determination was part of a program to investigate the relation between structure and physical properties, in particular melting point. Nylon 6 melts 50°C. lower than its isomer nylon 66 (—NH (CH2)6NH·CO (CH2)4CO—)p; it had been suggested that this was due to deficient hydrogen-bond formation in nylon 6 crystallites. The unit cell contains eight chemical units (—NH (CH2)5CO—) and is monoclinic with a = 9.56 A., b = 17.24 A., c = 8.01 A., and β = 671/2°. Calculated density = 1.23. Observed density for a drawn monofilament = 1.16. The structure consists of planar chains of CH2 groups and amide groups tilted 7° from the (001) plane. Alternate chains in this plane are oppositely directed, an arrangement which allows all hydrogen bonds to be made perfectly. The hydrogen-bonded sheets of atoms are packed in an “up-and-down” staggered configuration along the c-axis. Distances between atoms in neighboring molecules are all normal van der Waals contact distances. It appears, from a general survey of polyamide melting points published elsewhere, that the determining factor is the number of CH2 groups between the amide “anchor points” - polymers with odd numbers of CH2 groups melt lower than those with even numbers. The present work shows that the odd number of CH2 groups in this polymer does not lead to deficient hydrogenbond formation, and that the lower melting point of nylon 6 as compared with nylon 66 must be ascribed to some other cause, possibly connected with the propagation of vibrations along odd-numbered chain segments.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1955.120178401
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  • 2
    Electronic Resource
    Electronic Resource
    Infrared study of oxidation of elastomersContribution No. 215 from the Research Laboratory of The Goodyear Tire & Rubber Co. (1955)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 15 (1955), S. 51-67 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Infrared absorption spectra were used to study the structural changes resulting from oxidation in a number of unvulcanized, purified polymers under a variety of experimental conditions. The results showed that as oxidation progressed, the structural changes which were detected were qualitatively the same for all of the polymers under all of these experimental conditions. Correlation of volumetric measurements with spectral data indicated that considerably more oxygen was absorbed by the polymer samples before structural changes could be detected than the minimum amount required for the initial detection of the hydroxyl and carbonyl structures. From the interpretation of information from the absorption spectrum, it is believed that the structural evidence is in substantial agreement with current theories on autoxidation. Although the initial hydroperoxide formation is not observed in the spectrum, it is quite probable that this reaction takes place with almost immediate decomposition which results in a net hydroperoxide concentration so low as to make infrared methods insensitive for its detection. Correlation of physical properties with structural studies indicate that little change in these properties take place until the hydroxyl and carbonyl structures become evident in the infrared spectrum.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1955.120157905
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  • 3
    Electronic Resource
    Electronic Resource
    Determination of chain length by light scattering without knowledge of concentration (1955)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 17 (1955), S. 133-135 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1955.120178315
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  • 4
    Electronic Resource
    Electronic Resource
    Fluorine-containing polymers. II. 1, 1-dihydroperfluoroalkyl acrylates: Preparation of monomersContribution No. 57 from the Central Research Department, Minnesota Mining and Manufacturing Co. We wish to acknowledge the financial support of the Wright Air Development Center, Air Material Command, Wright-Patterson Air Force Base (Dayton, Ohio), for the work reported here.1 (1955)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 15 (1955), S. 515-519 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Acrylate esters of seven n-1,1-dihydroperfluoroalkanols have been synthesized. The esters are: 1,1-dihydroperfluoroethyl-; 1,1-dihydroperfluoropropyl-; 1,1-dihydroperfluorobutyl-; 1,1-dihydroperfluoropentyl-; 1,1-dihydroperfluorohexyl-; 1,1-dihydroperfluorooctyl-; and 1,1-dihydroperfluorodecyl acrylates. Since these alcohols were difficult to esterify using conventional procedures, acrylyl chloride or acrylic acid plus perfluoroacetic anhydride have been empolyed in this work.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1955.120158018
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  • 5
    Electronic Resource
    Electronic Resource
    Approximate equations for time of batch fractionation (1955)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 1 (1955), S. 111-117 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Analytical expressions are obtained for the calculation of the time required for batch rectification of binary feeds which may be treated by assuming constant relative volatility and no column holdup. The equations cover constant reflux operations and varying reflux constant product operations for the two cases involving either a large or a small number of theoretical stages. The latter type of calculation has hitherto been possible only by tedious graphical methods. This paper introduces novel pseudoequilibrium curves which lead to simple equations of considerable accuracy. The equations obtained may be rearranged or modified so that other factors such as sharpness of fractionation may be represented analytically.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690010117
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  • 6
    Electronic Resource
    Electronic Resource
    Turbulence in falling liquid films (1955)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 1 (1955), S. 178-184 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: On the basis of fluid dynamic and heat transfer studies on falling-film towers by various investigators, it has been commonly accepted by most workers that the liquid flow is essentially streamline in nature for liquid-film Reynolds numbers under 1,800 to 2,000; conseuquently it would be expected that the rate of physical gas absorption in such liquid films could be predicted directly from a knowledge of molecular diffusion rates.Measurements of the absorption of pure gases in falling liquid films at low Reynolds numbers substantiated the findings of other investigators that the mass transfer rates were manyfold greater than could have been predicted if molecular diffusion were the only transfer process. Increased interfacial area due to rippling of the liquid films could not account for the large increase in mass transfer rates found, and experiments with the addition of a dye stream to the liquid at the freer interface indicated turbulence.Dissolution rates of slightly soluble solids coated on the tube wall to liquid films were measured and showed that the liquid film was not in laminar flow even for Reynolds numbers as low as 300.An explanation is proposed which resolves these apparently conflicting results between momentum and heat and mass transfer, based on the fact that mass transfer measurements provide a more sensitive test for the presence of turbulence than do momentum or heat transfer measurements.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690010209
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  • 7
    Electronic Resource
    Electronic Resource
    Membrane separations in the liquid phase (1955)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 1 (1955), S. 215-219 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690010214
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  • 8
    Electronic Resource
    Electronic Resource
    Transport of momentum and energy in a ducted jet: III. Correlation of profiles of total momentum and energy flux in a nonisothermal jet discharging into a duct (1955)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 1 (1955), S. 69-73 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The data in the first paper of this series on the distribution of momentum and energy in nonisothermal air streams mixing in a straight duct were correlated by the methods described in the second paper. Mixing indexes were evaluated and used to correlate profiles of total momentum and stagnation temperature at various sections of the duct.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690010110
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  • 9
    Electronic Resource
    Electronic Resource
    Numerical solution of two-dimensional heat-flow problems (1955)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 1 (1955), S. 505-512 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Two-dimensional heat flow frequently leads to problems not amenable to the methods of classical mathematical physics; thus, procedures for obtaining approximate solutions are desirable. A recently introduced finite-difference method, known to be applicable to problems in a rectangular region and involving much less calculation than previous methods, is extended by example to cases of more practical interest. Although all three examples given are steady state, unsteady state problems may also be attacked successfully by the method. The first example is that of flow around a corner and indicates that a more complicated region than a rectangle can be treated. Then a problem involving a radiation-boundray condition is given; as this condition is nonlinear, the method is extended to more general equations. The last example involves point heat sources and sinks in an elliptical region and so extends the method to treat curved boundaries (as distinguished from polygonal domains) and singular points. It is believed that materially less calculation is necessary by this method than for previous procedures.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690010421
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  • 10
    Electronic Resource
    Electronic Resource
    Transport of momentum and energy in a ducted jet: II. Theoretical study of turbulent transport of momentum, energy, and matter in ducted coaxial streams (1955)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 1 (1955), S. 61-69 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This paper concerns the kinetics of the processes that take place when a high-velocity jet of fluid mixes turbulently with a low-velocity, induced stream of the same fluid in a duct of uniform diameter. Semi-two-dimensional solutions of the equations of transport involving two empirical coefficients were obtained by application of Reichardt's hypothesis and three assumptions: (a) a negligible fraction of the flow entity (energy, mass, or momentum) is lost at the wall and the presence of the boundary layer may be ignored, (b) the static pressure is uniform over a section of the duct, and (c) the turbulence pattern is similar to that in free jets except that the duct wall limits the growth of the scale of the turbulence. A mixing index, which is a measure of the degree to which the jet stream remains unmixed with the induced stream at any point, was defined and related to the geometry of the system and the flow parameters by means of the theoretical equation, and a method of evaluating the empirical coefficients for a typical case of momentum transport was described.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690010109
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