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  • 1
    Electronic Resource
    Electronic Resource
    Miscibility of poly(caprolactone)/chlorinated polypropylene and poly(caprolactone)/poly(chlorostyrene) blends (1982)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 27 (1982), S. 559-568 
    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: Poly(caprolactone) (PCL) was blended with poly(chlorostyrene) (PSCI) and chlorinated polypropylene (PPCl). A single glass transition temperature Tg was found for these mixtures, indicating their miscibility. PCL crystallizes in these blends when the chlorinated polymer content is not too high. Otherwise, Tg becomes higher than the melting point of PCL and the high viscosity of the medium hinders the crystallization. The miscibility of PCL/PPCI blends cannot be due to hydrogen bonding between the α-hydrogens of the chlorinated polymer and the carbonyl group of the polyester since PPCI does not have available a large number of α-hydrogens. It is suggested that a dipoledipole —C=O…Cl—C— interaction is responsible for the observed miscibility phenomenon and that this interaction is probably also responsible for the miscibility between all other polyesterchlorinated polymer mixtures. Finally, it was observed that poly(α-methyl-α-n-propyl-β-propiolactone), poly(α-methyl-α-ethyl-β-propiolactone) and poly(valerolactone) are not miscible with PSCI or PPCl, despite the fact that they are miscible with poly(vinyl chloride).
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1982.070270219
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  • 2
    Electronic Resource
    Electronic Resource
    Epoxy resin cure. II. FTIR analysis (1984)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 29 (1984), S. 3713-3726 
    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: Fourier transform infrared (FTIR) spectroscopy is used to determine the cure rate of an epoxy resin consisting of Tetraglycidyl-4,4′-diaminodiphenyl methane (TGDDM) and diaminodiphenylsulfone (DDS). Cure rates at 120 and 160°C are shown to increase noticeably when 1% BF3-MEA is added to either TGDDM to TGDDM plus DDS. Fluoroboric acid is shown to increase the cure rates even more than the BF3-MEA. These Results combined with the NMR results in the accompanying article indicate that BF3-MEA is not a catalyst for epoxy resin cure. Instead it is rapidly hydrolyzed to fluoroboric acid which acts as the catalyst.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1984.070291207
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  • 3
    Electronic Resource
    Electronic Resource
    Equilibrium acid concentrations in hydrolyzed polyesters and polyester-polyurethane elastomersPresented in part at the 184th meeting of the American Chemical Society, Kansas City, MO, September 12-17, 1982, Ref. 1. (1983)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 28 (1983), S. 3779-3792 
    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: Equilibrium acid concentrations, [Ae], were determined in butylene adipate and caprolactone polyesters, of low molecular weight, and in thermoplastic polyurethane elastomers based on these polyesters. Values of [Ae] of the polyesters at 85°C were 0.7, 1.3, and 3-4 × 10-3 mol/g at relative humidities (RH) of 25%, 50%, and 93%, respectively. [Ae] of the thermoplastic elastomers at 85°C were about 3 and 7 × 10-4 mol/g at 10% and 25% RH, respectively. Values of [Ae] were not very dependent on temperature at constant RH. Equilibrated thermoplastic elastomers had low molecular weights and poor physical properties. Consequently, equilibration does not set a practical limit on hydrolytic degradation, even at low RH. Equations were developed that described the variation in acid content with time. Rate constants for hydrolysis and esterification increased as RH decreased. Reesterification in the elastomers in the absence of water is too slow to be a useful method of decreasing hydrolytic damage.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1983.070281218
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  • 4
    Electronic Resource
    Electronic Resource
    Epoxy resin cure. I. Fluorine-19 NMR of boron trifluoride monoethylamine and fluoroboric acid (1984)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 29 (1984), S. 3697-3711 
    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: Fluorine-19 NMR is used to examine the role of boron trifluoride monoethylamine (BF3-MEA) in epoxy resin cure. Spectra were first recorded in a variety of solvents suitable for dissolving different epoxy resins. All spectra contained a peak due to fluoroboric acid. Spectra of BF3-MEA in orthodichlorobenzene were then recorded at elevated temperatures. The floroboric acid peak area increased, indicating that the BF3-MEA was being hydrolyzed. Results indicate that, at temperatures above 100°C, BF3-MEA is completely hydrolyzed within 5 min to fluoroboric acid.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1984.070291206
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  • 5
    Electronic Resource
    Electronic Resource
    The effects of thermooxidative aging on the fatigue behavior of a structural adhesiveCorrected proofs received September 19, 1984 (1984)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 29 (1984), S. 3499-3511 
    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 kinetics of autoxidation of FM-73U, a rubber-modified epoxy adhesive, were investigated by Fourier transform infrared analysis. Absorbance spectra for thin samples aged in hot, moist, oxygen-rich environments were used to assess a plausible reaction mechanism; rate constants, Arrhenius plots, and oxidation rates were determined. Concurrently, crack growth rates were measured on specimens which had been exposed to similar environments for periods of up to 8 months. Paris parameters measured in these tests were correlated with the results of the oxidation studies. These correlations were used to predict the crack growth rate of the adhesive after 10 years of aging in ambient conditions. Although the prediction indicates that the adhesive becomes more brittle with age, the changes are not severe.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1984.070291125
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  • 6
    Electronic Resource
    Electronic Resource
    Organic surface film contamination of Vitallium implants (1981)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 15 (1981), S. 843-851 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Conventional finishing and polishing techniques used to prepare Vitallium subperiosteal dental implant castings were found to produce low energy surfaces as measured by critical surface tension. Standard metallographic preparation gave slightly higher values. Glow discharge cleaning of both types of polished surface gave much higher critical surface tension values. This suggests the presence of an organic film after surface polishing of the implant which may later affect tissue reaction, in particular attachment, as has been noticed in related animal studies.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820150609
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  • 7
    Electronic Resource
    Electronic Resource
    Propriétés viscoélastiques de la poly(α,α-diéthyl-β-propiolactone) (1980)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 181 (1980), S. 857-867 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The viscoelastic properties of poly(α,α-diethyl-β-propiolactone) were investigated in the linear range using stress relaxation and dynamic mechanical methods. Using Ferry's reduction method, a horizontal shift factor was determined at each temperature, that satisfactorily agreed with the WLF equation in the transition zone. No vertical shift was required to superimpose different relaxation curves. The apparent activation energy was temperature dependent and passed through a maximum near Tg whose value is (311 ± 2)K. The relaxation spectrum has been calculated according to the first method of approximation of Schwarzl and Staverman. It consists of a high intensity plateau at shorter times, a wedge type portion with a slope of -0,15 and a low intensity plateau at longer times. Dynamical mechanical measurements revealed a β relaxation peak at 333 K and yielded the evidence of a γ peak around 120 K.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1980.021810408
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  • 8
    Electronic Resource
    Electronic Resource
    A critical evaluation of models for complex molecular dynamics: Application to NMR studies of double- and single-stranded DNA (1983)
    New York : Wiley-Blackwell
    Biopolymers 22 (1983), S. 2703-2726 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The nature of internal and overall motions in native (double-stranded) and denatured (single-stranded) DNA fragments 120-160 base pairs (bp) long is examined by molecular-dynamics modeling using 13C-nmr spin-relaxation data obtained over the frequency range of 37-125 MHz. The broad range of 13C frequencies is required to differentiate among various models. Relatively narrow linewidths, large nuclear Overhauser enhancements (NOEs), and short T1 values all vary significantly with frequency and indicate the presence of rapid, restricted internal motions on the nanosecond time scale. For double-stranded DNA monomer fragments (147 bp, 24 Å diam at 32°C), the overall motion is that of an axially symmetric cylinder (τx = ∼10-6 s;τZ = ∼1.8 × 10-8s), which is in good agreement with values calculated from hydrodynamic theory (τx = ∼1.8 × 10-6 s; τZ = ∼2.7 × 10-8 s). The DNA internal motion can be modeled as restricted amplitude internal diffusion of individual C—H vectors of deoxyribose methine carbons C1′, C3′, and C4′, either with conic boundary conditions (τw = ∼4 × 10-9 s, θcone = ∼21°) or as a bistable jump (τA = τB = ∼2 × 10-9 s, θ = ∼15°). We discuss the critical role in molecular-dynamics modeling played by the angle (β) that individual C—H vectors make with the long axis of the DNA helix. Heat denaturation brings about increases in both the rate and amplitude of the internal motion (described by the wobble model with τW = ∼0.2 × 10-9 s, θcone = ∼50°), and overall motion is affected by becoming essentially isotropic (τx = τZ = ∼5 × 10-8 s) for the single-stranded molecules. Since 13C-nmr data obtained at various DNA concentrations for C2′ of the deoxyribose ring is not described well by the above models, a new model incorporating an additional internal motion is proposed to take into account the rapid, extensive, and weakly coupled motion of C2′.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360221214
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  • 9
    Electronic Resource
    Electronic Resource
    Antifreeze glycoproteins: Influence of polymer length and ice crystal habit on activityPortions of this work have been published in a preliminary letter (Ref. 1) and have been presented at the American Chemical Society National Meeting, 1982, St. Louis, Mo. Parts of this material were taken from the theses of M.J.K. and T.S.B. submitted to the Graduate Division, University of California, Davis in partial fulfillment of the requirements for an M.S. degree. (1984)
    New York : Wiley-Blackwell
    Biopolymers 23 (1984), S. 1379-1395 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effect of the ice crystalline habit and the length of the polymer on the ability of the antifreeze glycoproteins (AFGP) from polar fish to depress the freezing temperature of water was investigated. The low-molecular-weight components of the glycoproteins, AFGP- 6-8, are inactive when a solution of such a sample is nucleated at -6°C. A solution of large AFGP (1-4) is fully functional under the same conditions. The low-molecular-weight components differ from the height-molecular-weight components in that they contain some proline replacing the alanine in the Ala-Ala-Thr · disaccharide polymer unit. In the present experiments, antifreeze activity was examined in the presence of two different forms of ice crystal growth habits, and homodimders of AFGP 6 and 8 were prepared to investigate the function of polymer length and the on antifreeze activity at different degrees of supercooling. The results indicate that the ice crystal growth habit and the introduction of proline into the polymer unit may be responsible for the loss of activity at deep supercooling (-6°C) of AFGP 6-8. The loss in the ability of AFGP to depress the freezing temperature of water at deep supercooling is not solely due to polymer length, as carbodiimide-linked dimers of AFGP 6 do not function under these freezing conditions. A Model of antifreezing action based on Langmuirian adsorption of AFGP on the ice surface and direct competition between water and AFGP molecules for the incorporation sites in the ice crystal lattice is presented.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360230720
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  • 10
    Electronic Resource
    Electronic Resource
    Miscibility of polycaprolactone/chlorinated polyethylene blends (1982)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 20 (1982), S. 191-203 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Blends of polycaprolactone (PCL) with chlorinated polyethylenes (PECls) having chlorine contents of 25, 30, 36, 42, and 48% by weight were prepared and studied by differential scanning calorimetry and small-angle light scattering (SALS). It was found that blends made with PECls containing 30% or more chlorine are completely miscible with PCL (a single glass transition temperature Tg is found) while the PCL/PECl(25) blends are immiscible. PCL crystallizes in the miscible blends at any composition and it has an enthalpy of fusion which decreases only slightly with PECl content. Blends in the PECl composition interval of 0-80% are spherulitic, as shown by SALS, but a rodlike morphology is found at the 85% composition and dispersed crystals are observed at higher compositions. It is suggested that the k parameter of the Gordon-Taylor equation can be taken as a measure of the strength of the specific interaction between PCL and PECl. Low values of k (0.26 and 0.35) are found for PCL/PECl blends but a higher value of k (0.51) has been reported for PCL/poly(vinyl chloride) (PVC) blends, indicating a stronger interaction in the latter mixtures. In agreement with these findings poly(α-methyl-α-n-propyl-β-propiolactone) and poly(valerolactone) are not miscible with PECl, whereas they were previously shown to be miscible with PVC.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1982.180200203
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