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  • 1970-1974  (10)
  • 1920-1924
  • Polymer and Materials Science  (10)
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  • 1
    Electronic Resource
    Electronic Resource
    Multiple endotherm melting behavior in relation to polymer morphology (1972)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 1273-1283 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The two endotherms found during DSC analysis of annealed or drawn poly(ethylene terephthalate), PET, are discussed in greater. detail. Earlier workers proposed that the endotherms were the result of separate morphologies, i.e., extended-chain and folded-chain crystals, but more recently Roberts and others have presented data on the effect of DSC heating rate on annealed PET endotherm areas which indicate that the higher temperature endotherm is the result of recrystallization in the DSC. The present work explains the reasons for recrystallization, and presents data showing that samples cooled at various rates from the melt also exhibit recrystallization in the DSC, in much the same manner as samples annealed for different lengths of time. Further, by prolonged annealing before analysis, part of the recrystallization exotherm can be observed in the DSC scan. Drawn nylon 66 also exhibits recrystallization in the DSC, in a manner similar to annealed or slowly crystallized PET. The amount of material that recrystallizes is determined by the time and supercooling available between first melting and the ultimate recrystallization temperature, i.e., a temperature at which there is too little time and temperature driving force for further recrystallization to occur. Infrared absorption data show an increase in “regular” fold content during prolonged annealing of PET, while dynamic mechanical data show a marked decrease in a dispersion that is likely associated with the looser fold crystal morphologies. Annealed PET does superheat in the DSC, leaving unanswered the question as to whether any partially extended material is present along with the regular-fold material. For cold-drawn PET, the infrared data indicate disappearance of regular folds and the dynamic mechanical data indicate disappearance of the looser folds. Cold-drawn PET also superheats. These data indicate a likelihood of at least partially extended morphologies in cold-drawn PET; these observations do not apply to PET drawn at high temperatures or to polyethylene.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1972.160100707
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Relation between the network structure and dynamic mechanical properties of a typical amine-cured epoxy polymer (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 437-445 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The dynamic mechanical properties of a series of epoxy polymers of known network structure have been investigated. It was shown that the distance between crosslinks could be predicted from either the shift in the glass transition temperature Tg or by use of the dynamic modulus above Tg. The front factor in the equation of state for rubber elasticity was near unity for stoichiometric equivalence of epoxy and amine and increased slowly with excess of either component.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1970.160080309
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    The effect of soluble cations on the bonding of epoxy resins to aluminum (1974)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 18 (1974), S. 343-349 
    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 bond strength of an amine-cured epoxy resin to etched aluminum washed with, or washed with and immersed in, 10°C tap water was found to be greater than joints similarly pretreated in 10°C distilled water. The higher bond strength was found to be induced by soluble cations of less than 0.8 Å radius; larger cations had no effect. When aluminum is etched in a solution of chromic acid at 65°C, the aluminum surface is oxidized to γ-Al2O3. It is possible that the small, soluble cations can occupy the cationic vacancies in the defect spinel structure of the γ-Al2O3 and reduce the negative charge on the surface of the aluminum joints. Joints pretreated in 60°C tap water exhibited higher bond strengths than those pretreated in 60°C distilled water, as the growth of a thick, weak layer of bayerite was inhibited by large anions present in the tap water.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1974.070180203
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  • 4
    Electronic Resource
    Electronic Resource
    Surface interaction between aluminum and epoxy resin (1974)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 18 (1974), S. 2243-2247 
    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: Titration and infraed analysis found no primary chemical bonds between etched or unetched aluminum and an amine-cured epoxy resin. Titration of a very small amount of resin in contact with the large surface area of aluminum dust revealed no drop in epoxy content when oxygen was excluded. The spectra of a bulk-cured epoxy resin were essentially superimposable on the spectra obtained by attenuated total reflectance and specular reflectance of a very thin layer of the cured epoxy resin bonded to aluminum plate. Analysis of uncured epoxy resin in contact with aluminum plate and powder, subjected to the cure cycle in air, indicated that the epoxy ring is oxidized to a carboxylic acid. When air is excluded, no loss of epoxy groups is observed.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1974.070180803
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  • 5
    Electronic Resource
    Electronic Resource
    The effect of polymer network structure upon the bond strength of epoxy-aluminum joints (1972)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 16 (1972), S. 1721-1733 
    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 bond strength to aluminum of Epon 828 cured with various amounts of methylene dianiline has been investigated as a function of the resin network structure. In order to meet this objective, a torsional test for bond shear strength was developed, and fully cured resins with different network structures were prepared. The effects of the rate of loading of the joint and the aluminum surface pretreatment on the bond strength were also examined. Very high bond shear strengths, in excess of 9000 psi, were found for joints which after machining had been polished, vapor degreased, and treated with dilute sulfuric acid-potassium dichromate solution. It was found for these joints that the average bond strength decreased as the molecular weight between crosslinks increased. For the joints without acid-dichromate treatment, the failures were adhesive, and the network structure did not seem to significantly affect the bond strength. There are indications that chemical bonding occurred in the case of the acid-dichromatetreated joints; the decrease in bond strength as per cent excess amine and Mc increased is possibly associated with a decreased amount of chemical bonding. The bond strength increased to a limiting value as the rate of testing increased.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1972.070160710
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  • 6
    Electronic Resource
    Electronic Resource
    The effect of time and type of water pretreatment on the bond strength of epoxy-aluminum joints (1974)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 18 (1974), S. 335-342 
    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 bond strength of unetched aluminum-epoxy joints induced by tap and distilled water pretreatment at 10°C increased to a maximum, then decreased as a function of immersion time. In distilled water, the maximum bond strength occurs after an immersion time of about 1 hr, after which the bond strength decreases. In the case of tap water pretreatment, the maximum bond strength occurred at about 12 hr of immersion time. The bond strengths at the maxima found for the tap water-pretreated samples were greater than those found at the maxima for the joints pretreated in distilled water. Growth of the hydrated oxide bayerite is proposed as the controlling factor; the bayerite grows more rapidly and less perfectly in distilled water than in tap water. Thick layers of bayerite are structurally weak, while thin layers seem to promote adhesion. A slight surface roughness effect was also observed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1974.070180202
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  • 7
    Electronic Resource
    Electronic Resource
    Sonic modulus in a porous system (1970)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 14 (1970), S. 2412-2415 
    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
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1970.070140921
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  • 8
    Electronic Resource
    Electronic Resource
    The collapse process in acrylic fibers (1970)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 14 (1970), S. 2402-2406 
    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
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1970.070140919
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  • 9
    Electronic Resource
    Electronic Resource
    Morphology of uniaxially oriented poly(ethylene terephthalate) (1973)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 11 (1973), S. 1779-1791 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The morphological character of uniaxially oriented poly(ethylene terephthalate) (PET) films was investigated as a function of draw ratio. Dynamic mechanical, infrared, and crystallite-size measurements were made on the samples. In addition, selective degradation experiments and molecular weight determinations were employed. The dynamic mechanical measurements indicated a sharp decrease in irregular folds for draw ratios of 3.0 and higher, which also coincided with the essentially complete disappearence of regular folds (from the 988 cm-1 band in the infrared spectra) in unannealed samples. Infrared studies of drawn samples annealed under different conditions gave evidence in support of a structure in which the chains are stretched out. Apparent crystallite-size measurements showed a sudden increase in length of the crystals in the direction of the draw beyond a draw ratio of 3.0. Molecular weight measurements showed a large increase in average chain length in the residue after selective degradation of amorphous material and folds; undrawn and slightly drawn samples gave a much lower Mn. Based on these observations, it is postulated that for higher draw ratios and present drawing conditions, the crystals are of the straight chain type, somewhat similar to the fringed-micelle crystal concept.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1973.180110910
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  • 10
    Electronic Resource
    Electronic Resource
    Chain-folding measurements in annealed poly(ethylene terephthalate) (1973)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 11 (1973), S. 1793-1801 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Chain folding in unoriented poly(ethylene terephthalate) (PET) films has been investigated as a function of annealing time and temperature. To meet this objective dynamic mechanical, infrared, and molecular weight measurements were used, together with selective chemical degradation to remove chain folds and amorphous regions. The β dispersion in the dynamic mechanical spectrum of PET is here tentatively associated with motions of methylene and/or carboxyl groups in irregular chain folds; the β dispersion is not found in quenched amorphous polymer, in polymer where amorphous regions and chain folds have been removed, or in highly annealed PET where the irregular folds have regularized. Upon mild crystallization and annealing (30 min at 110°C) of initially amorphous film a large β dispersion appears and then diminishes upon further annealing at 220°C. As the β dispersion diminishes, the infrared regular fold band increases more than the crystallinity band, indicating regularization of folds. The molecular weight of the degraded residue corresponds approximately to typical fold-period dimensions (∼130 Å), and increases on annealing as expected from lamellar thickening. The degradation process has, by fold removal, reduced the chains in the crystals to a very short, uniform length.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1973.180110911
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