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  • 1
    Electronic Resource
    Electronic Resource
    Synthesis of hydroxyl-terminated polycarbonates of controlled number-average molecular weight (1982)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 20 (1982), S. 2289-2301 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Hydroxyl-terminated polycarbonates are important starting materials for the synthesis of multiblock copolymers. Earlier papers from our laboratory and elsewhere have demonstrated their utility in siloxane, aryl ether, and ester systems. One synthesis problem that must be addressed is the control of the number-average molecular weight and hence block size of the polycarbonate oligomeric precursor. The facile phosgene-hydroxyl reaction is often difficult to monitor precisely. The present article describes a novel, simple, and convenient technique for the synthesis of hydroxyl-terminated polycarbonates of well-controlled number-average molecular weight. The approach involves an in situ blocking of some of the phenolic groups either prior to or during phosgenation. The protecting groups are easily removed after the polymerization is complete. In a practical laboratory experiment the technique does not require any additional step beyond that necessary for the preparation of nonfunctional polycarbonates of controlled molecular weight. The method is demonstrated in this article with the polycarbonate of bisphenol-A via the use of trimethylchlorosilane, trifluoroacetic anhydride, and trifluoroacetic acid as blocking groups. Ultraviolet, 19F-NMR, and 1H-NMR measurements as well as vapor-pressure osmometry were used to characterize the oligomers.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1982.170200831
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  • 2
    Electronic Resource
    Electronic Resource
    Assessment of the adhesive bond properties of allyl 2-cyanoacrylate (1981)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 26 (1981), S. 1941-1949 
    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 adhesive bond of allyl 2-cyanoacrylate between steel substrates has been analyzed and compared to that of ethyl 2-cyanoacrylate. Mechanical strength as well as thermomechanical, calorimetric, thermogravimetric, and dynamic mechanical response was observed. It was demonstrated that the allyl 2-cyanoacrylate bonds exhibit improved temperature resistance owing to the formation of heat-induced crosslinks in the adhesive layer, resulting in much improved lap-shear strengths. Scanning electron microscopy of the fracture surfaces showed that plastic deformation occurred in the allyl 2-cyanoacrylate adhesive after thermal aging, while interfacial and brittle failure dominated all other cases.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1981.070260618
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  • 3
    Electronic Resource
    Electronic Resource
    Correlation of solubility in polydimethylsiloxane and polyisobutylene systems (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 30 (1985), S. 307-315 
    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: Solubility data of organic probes in polydimethylsiloxane (PDMS) and polyisobutylene (PIB) obtained by inverse gas chromatography (IGC) were collected from the literature and analyzed. Applying the principle of corresponding states, empirical correlations were derived and presented for the estimation of solubilities of nonpolar and slightly polar probe molecules in these polymers. Estimation of other thermodynamic properties, such as activity coefficient of the solute, Henry's law constant, Flory-Huggins interaction parameter, and heat of solution through the use of these correlation equations, was demonstrated.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1985.070300126
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  • 4
    Electronic Resource
    Electronic Resource
    Solubility of nonpolar and slightly polar organic compounds in low-density polyethylene by inverse gas chromatography with open tubular column (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 30 (1985), S. 1815-1826 
    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: Inverse gas chromatography (IGC) with open tubular column was used to determine low pressure solubilities of 13 organic solutes in low-density polyethylene (LDPE) for temperatures from 50 to 175°C. Based on the principle of corresponding states, two simple correlation equations were developed for estimation of the solubility of nonpolar and slightly polar solutes in rubbery and molten LDPE.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1985.070300503
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  • 5
    Electronic Resource
    Electronic Resource
    Viscoelastic character of poly(ethylene oxide) in aqueous solutions: Effect of shear rate, concentration, salt, and anionic surfactant (1986)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 31 (1986), S. 333-340 
    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 technique useful for estimating the viscoelastic properties of dilute solution poly(ethylene oxide) was developed. With this technique, the effect of concentration, shear rate, presence of salt and/or anionic surfactant, and molecular weight on the viscoelastic properties in dilute solution were determined. Differences in the viscoelastic properties of commercial grade materials were observed. An explanation for the differences in salt and surfactant solutions based on formation of a weak ionic network is presented.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1986.070310204
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  • 6
    Electronic Resource
    Electronic Resource
    Effect of metal particle incorporation on adhesive and electrical properties of acetylene-terminated polyisoimide prepolymers (1988)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 36 (1988), S. 1295-1304 
    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: Modification of properties of an addition-curing polyisoimide prepolymer is achieved by the incorporation of small metal particles. No evidence for the modification of the cure chemistry of the prepolymer is observed. Physical modification of the system is observed in electrical, dynamic mechanical, and adhesive properties. Compositions containing various volume fractions of metal and polymer were prepared. Two different molecular weights of prepolymer were studied. Samples were prepared by fabricating single overlap adhesive specimens to aluminum. These lap shear specimens were then used for the electrical and adhesive properties of the material. The electrical properties improved markedly at above 25 volume percent metal loading. The adhesive properties to aluminum showed a maximum at 20-25 volume percent loading. X-ray photoelectron spectroscopy was used to examine adhesive failure surfaces.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1988.070360605
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  • 7
    Electronic Resource
    Electronic Resource
    Accelerated imidization reactions using microwave radiation (1992)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 30 (1992), S. 1647-1653 
    Details
    ISSN: 0887-624X
    Keywords: microwave processing ; imidization ; rapid curing ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Microwave radiation has been clearly shown to result in enhancement of the rate of reaction for an imidization reaction. Analysis of the kinetic parameters showed that the apparent activation energy for the reaction was reduced from 105 to 55 kJ/mol, under the conditions of this experiment. The mechanism which has been proposed to explain this enhancement is based on the concept of a nonuniform temperature on a molecular scale, rather than a true reduction in the activation energy. © 1992 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1992.080300817
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  • 8
    Electronic Resource
    Electronic Resource
    The role of colloid formation, imidization, and aggregation in the structure of BTDA-ODA polyimide films modified with gold (1988)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 26 (1988), S. 1641-1655 
    Details
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: High-temperature polyimide films with metallic gold surfaces can be fabricated by the incorporation of a soluble metal salt into a solution of polyamic acid. Thermal treatment of these solutions produces the polyimide, decomposes the metal salt to metallic gold, and promotes the formation and growth of the metallized surface. What appeared to be a continuous metallic surface was actually composed of large gold aggregates. It is suspected that the formation of colloidal gold during the initial thermal treatment provides precursors to the large metal aggregates. Thermal treatment has been shown to influence the size and distribution of the aggregates. The shape of the aggregates suggests that diffusion-limited aggregation may be responsible for the unique shape of some of the gold aggregates.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1988.090260807
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  • 9
    Electronic Resource
    Electronic Resource
    Temperature and stress effects in the creep of aramid fibers under transient moisture conditions and discussions on the mechanisms (1992)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 30 (1992), S. 1391-1400 
    Details
    ISSN: 0887-6266
    Keywords: creep of aramid fibers, temperature and stress effects ; poly(p-phenylene terephthalamide), mechano-sorptive creep mechanisms ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In a previous study, a mechanosorptive phenomenon in poly(p-phenylene terephthalamide) fibers was reported. In this article, the mechanosorptive creep mechanism of aramid fibers and the temperature and stress influences on the mechanosorptive creep behavior of aramid fibers are addressed. Test results indicate that logarithmic creep rates and the mechanosorptive effects increase with temperature. The creep activation energies of the fibers tested are: 20 kJ/mole for the cyclic moisture condition, 4.4 kJ/mole for a high equilibrium moisture condition (RH = 95%), and 7.8 kJ/mole for a low equilibrium moisture condition (RH = 5%). Increase in stress may increase the logarithmic creep rates but may reduce the mechanosorptive effect. Aramid fibers contain hydrogen bonds between rodlike crystallites oriented at small angles relative to the fiber axis. Transient moisture conditions may cause slippage of hydrogen bonded elements and result in accelerated crystallite rotations due to breakage of hydrogen bonds, thus causing increases in logarithmic creep rate. The obtained activation energies and the reduction in fiber elastic compliance due to creep deformation support the proposed mechanisms. © 1992 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1992.090301210
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  • 10
    Electronic Resource
    Electronic Resource
    Characterization of epoxy-surfactant interactions (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 36 (1998), S. 2781-2792 
    Details
    ISSN: 0887-6266
    Keywords: waterborne epoxy ; surfactant ; cooperativity ; Fox equation ; Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: We have investigated epoxies based on the diglycidyl ether of bisphenol A (DGEBA) cured with 2-ethyl-4-methylimidazole (EMI-24) in the presence of the nonionic surfactant Triton X-100. A goal was to determine if the viscoelastic properties of the epoxy-surfactant system differed when prepared in bulk form, as opposed to being cast as a thin film on the surface of E-glass cloth. Such a combination of materials has generated great interest for potential use in the construction of laminated circuit boards. Using dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), transmission electron microscopy (TEM), and atomic force microscopy (AFM), it was determined that the surfactant acts as a plasticizer and is miscible with the epoxy system in concentrations up to 15% by weight. The glass transition temperature (Tg) depression of the epoxy due to the surfactant was accurately described by the Fox equation. DMA master curves were constructed in the frequency domain. The temperature dependence of the shift factors was used to determine the fragility of each of the samples studied. It was found that the fragility (cooperativity) of the epoxy decreased as the concentration of surfactant increased, presumably due to a reduction of intermolecular constraints. The fragility of the combined epoxy-surfactant system increased when cast on the surface of the E-glass cloth. Results for our model epoxy-surfactant resin were in excellent agreement with those obtained using a commercially available aqueous waterborne epoxy resin. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 2781-2792, 1998
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
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