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  • Polymer and Materials Science  (22)
  • 1
    Electronic Resource
    Electronic Resource
    Structure of a novel polyimide (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 559-574 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The product of the thermal polymerization of ß-carboxymethyl caprolactam has been identified as a poly[(2,6-dioxo-1,4-piperidinediyl)trimethylene]. An indication of various chain conformations has been explained by the possible existence of two different conformations of the dioxopiperidine moiety. One conformation pertains to an equatorial position of the trimethylene moiety with respect to the plane of the imide group. The other is derived from a structural unit in which the trimethylene group is positioned axially to the plane of the ring. While the former conformation has been ascribed to the crystalline modification the latter appears to be the predominant structure of the polymer in formic acid solution as indicated by NMR analysis. In the glassy state the macromolecule is assumed to be composed of segments of either conformation. The unoriented linear polymer crystallizes upon annealing in positively birefringent spherulites. A triclinic unit cell with the following parameters: a = 9.64 A., b = 11.32 A., c = 15.80 A., α = 98°, β = 96°, γ = 114° has been found to contain eight structural units. The calculated density, 1.30 g./cm.3, agrees with experimental data. A crystal structure is proposed on the basis of the x-ray data.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060311
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  • 2
    Electronic Resource
    Electronic Resource
    FT-IR spectroscopic study on the photo- and photooxidative degradation of nylons (1987)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 25 (1987), S. 2301-2321 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The progress of photo- and photooxidative degradation of nylon films were studied by FT-IR spectroscopy. The gases evolved from the photolysis of various nylons and their model amides were also analyzed. The formation of double bonds, changes of crystallinity, and the effect of amino and carboxyl end groups has been studied and discussed. The band shapes of the IR spectra pertaining to the carbonyl groups formed by thermal oxidation or photooxidation were found to be very similar, suggesting that the two oxidation mechanisms might be similar. The broadness of these bands indicates that the carbonyl groups may belong to more than one species. The photodegradation of nylons containing purposely inserted carbonyl groups formed —CH=CH2 groups. Carbonyl groups formed during oxidation, and present either as keto groups or part of N-acylamide units make nylons susceptible to degradation reactions entailing mainly a Norrish type II mechanism.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1987.080250826
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  • 3
    Electronic Resource
    Electronic Resource
    Ethylene-chlorotrifluoroethylene copolymers. I. Synthesis and evaluation of compositions resistant to thermal stress cracking (1987)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 25 (1987), S. 1871-1886 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Copolymerization of ethylene, chlorotrifluoroethylene, and small amounts (less than 5 mol %) of a perfluoroalkylethylene yields terpolymers in which the concentration ratio of the ethylenederived units to the units derived from the fluorine-containing monomers is unity, indicating that the perfluoroalkylethylenes are incorporated at the expense of chlorotrifluoroethylene. The resulting polymer compositions are characterized by improved resistance to thermal stress cracking.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1987.080250713
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  • 4
    Electronic Resource
    Electronic Resource
    FT-IR spectroscopic study on the thermal and thermal oxidative degradation of nylons (1987)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 25 (1987), S. 2409-2424 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effects of heat and oxygen on nylon films were studied by FT-IR spectroscopy. Nylons 6, 66 and nylons containing carbonyl groups in either the diamine or the diacid moiety were prepared. Nylon films cast on aluminum were studied in an environmental chamber under controlled conditions. The progress of chemical and physical changes was monitored by FT-IR spectroscopy. Thermal energy caused largely an increase in crystallinity due to annealing and also an increase of nonhydrogen-bonded amide groups, which seemed to entail mainly amide groups from the amorphous region. The intensities of IR absorption bands related to the folded structure reduced as soon as heating began. The IR spectra of the carbonyl groups formed by thermal oxidation showed band shapes that indicated that the formed carbonyl groups were of many different origins. The presence of keto groups purposely inserted into the backbone chains increased the rate of oxidation. Pyrolysis of the nylons was also studied to supplement data obtained at lower temperatures.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1987.080250908
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  • 5
    Electronic Resource
    Electronic Resource
    Thermal properties of nylons containing carbonyl groups (1986)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 24 (1986), S. 1657-1674 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Nylons containing carbonyl groups in backbone chains were prepared and their response to heat was studied. The carbonyl groups were introduced using either HOOC(CH2)4CO(CH2)4COOH or H2N(CH2)5CO(CH2)5NH2 in the initial monomer compositions. In addition to pyrolysis of these polyamides, the progress of chemical and physical changes as a function of temperature was continuously monitored and analyzed by FT-IR spectroscopy on cast films placed in an environmental chamber. Introduction of the carbonyl groups into the polymer backbone resulted in a significant reduction of the thermal stability of the corresponding polyamide. Possible mechanisms for the thermal degradation entailing these carbonyl groups and N-acylamide compounds are discussed.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1986.080240723
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  • 6
    Electronic Resource
    Electronic Resource
    Mechanical relaxations in polyamides (1971)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 9 (1971), S. 867-886 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Dynamic mechanical measurements were carried out as a function of temperature (-100 to + 180°C) and frequency (3.5 to 110 cps) for a series of aliphatic terpolyamides, nylon 6 and nylon 12. Effect of crosslinking with toluene diisocyanate, of absorbed water, and of frequency are used to estimate the statistical segment length associated with the α′ relaxation. The effects of variations in the aliphatic chain length in the repeating unit on the temperature of the α′ relaxation are examined by means of copolymer rules with a view to explaining the reported insensitivity of the glass transition temperature of these polymers to changes in (CH2)/(amide) group ratio. From the estimated length of the segmental motion associated with the α′ relaxation it is inferred that in a series of polyamides of the type nylon X or nylon X,Y (where X or Y = 3, 4, 5, 6, etc.) there should be a relatively small change in the temperature of the α′ transition for those polyamides having X or Y less than about 45. Experiments which are intended to establish the position of the crystalline α-γ transition are discussed.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1971.160090508
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  • 7
    Electronic Resource
    Electronic Resource
    Caprolactam polymerization. Polymerization in backmix flow systems (1972)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 16 (1972), S. 929-934 
    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 reactor system consisting of a cascade of N perfectly mixed stirred tanks followed by a plug flow reactor was analyzed. Compared with a single-stage closed system, a substantial reduction in the total reaction time was indicated for systems using cascades of three or more stirred tanks. Calculations for both the micromixed and the segregated systems showed no significant difference between the respective total residence times.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1972.070160412
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  • 8
    Electronic Resource
    Electronic Resource
    Diffusion of water and caprolactam in nylon 6 melts (1973)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 17 (1973), S. 1663-1677 
    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 diffusions of both caprolactam and water from nylon 6 melts have been measured using a semiinfinite geometry. The process involving diffusion and chemical reaction was analyzed utilizing Higbie's penetration model and known kinetic data. The caprolactam and water diffusion coefficients are, respectively, 8 × 10-8 and 2.5 × 10-4 cm2/sec. Using the data, molecular weight profiles were obtained for both semiinfinite and cylindrical geometries as a function of melt depth and time.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1973.070170603
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  • 9
    Electronic Resource
    Electronic Resource
    Anionic polymerization of ∊-caprolactam activated with phosphadiazines (1977)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 15 (1977), S. 1349-1357 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Phenylphosphonyl-N,N′-biscaprolactam (I) and phenylphosphonyl-N,N′-bis(3,5-dimethylpyrazole) (II) were synthesized and found to be very efficient activators for the anionic polymerization of caprolactam when used in combination with strong bases such as sodium caprolactam. Polymers obtained in the presence of I and II had generally higher molecular weights and were less sensitive to thermal degradation upon molding than those whose preparation entailed the use of N-acetyl-caprolactam (III) as an activator. Thermal behavior and tensile properties indicated that the structure of these polyamides differs from that encountered in nylon 6 prepared with conventional anionic catalyst systems.
    Additional Material: 8 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1977.170150606
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  • 10
    Electronic Resource
    Electronic Resource
    Polymerization of vinylene carbonate in dimethyl sulfoxide (1978)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 16 (1978), S. 845-860 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pure vinylene carbonate polymerizes readily in dimethyl sulfoxide solutions upon initiation by azobisisobutyronitrile (AIBN). The monomer conversion is characterized by a limiting value which appears to be a function of the temperature and the initial concentrations of both the initiator and the monomer. Increasing both initiator concentration and temperature results in higher final conversions, whereas a maximum conversion is indicated for initial monomer concentrations in the range of 80% to 90%. Principal kinetic quantities were found to be adequately represented by the equations kd = 24.3 × 105 exp {-11300/RT} and kp(f/kt)1/2 = 46.3 × 105 exp {-8900/RT} for the temperature range of 50-80°C. The average degree of polymerization was found to be affected by chain transfer to the solvent. A value of 5.8 × 10-4 was determined for the corresponding chain transfer constant.
    Additional Material: 20 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1978.170160410
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