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  • Polymer and Materials Science  (33)
  • Development  (2)
  • 11
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 43 (1991), S. 2237-2247 
    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: Constant current electropolymerization of acrylamide was initiated on the surfaces of AS-4 graphite fibers. Electropolymerization was performed using an aqueous solution of acrylamide dissolved in dilute sulfuric acid solution. The progress of electropolymerization was followed by measuring the weight of polyacrylamide deposited onto the surfaces of a unit weight of graphite fiber per unit time. The rate of electropolymerization was obtained from the slope of the linear region of the polymer weight gain vs. electropolymerization time curve. The rate of electropolymerization onto AS-4 graphite fiber surfaces was found to depend on the initial monomer concentration, sulfuric acid concentration, and current density raised to the powers of 1.67, 0.02, 0.54, respectively. Molecular weight measurements on the electropolymerized polyacrylamide were done by solution viscometry. Number average molecular weights of 430,000, 220,000, and 193,000 were obtained for polyacrylamide, electropolymerized at 1 mA/g, 50 mA/g, and 100 mA/g respectively, consistent with classical radical polymerization kinetics.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
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  • 12
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1773-1781 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Either of the two endothermic melting peaks found by differential thermal analysis of nylon 66 may be converted to the other by appropriate choice of annealing conditions. The two peaks are considered due to the melting of two morphological species, forms I and II. Form I is relatively fixed in melting temperature, while the form II melting temperature varies with annealing conditions and can be either above or below form I. The two forms can be distinguished by whether or not the conversion I → II takes place; if the sample is in form II no change in the thermogram is observed under suitable conversion conditions. The conversion of form I to form II also takes place during cold drawing. It has been previously shown that form I results from rapid cooling from the melt, and form II results from slow cooling. Form I appears to be kinetically favored, while form II is thermodynamically preferred. The variability in the form II melting point is attributed to variable crystal size and/or perfection.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 13
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 437-445 
    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
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  • 14
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 61 (1996), S. 1049-1054 
    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: Emulsion copolymerization of N-phenylmaleimide (PMI) with styrene (St) was conducted via semibatch and batch methods. The effect of monomer mixture composition and method of copolymerization on copolymer structure-property relationships was investigated. The semibatch copolymers have a homogeneous molecular structure, exhibiting a single Tg which increases linearly with increasing PMI content. The batch copolymers have a heterogeneous molecular structure, exhibiting two Tg's, assigned to the polystyrene (PSt) and poly(PMI-co-St) components. The composition drift in the batch-copolymerized product, at different conversion levels, was examined by DSC and FTIR techniques. In general, the inherent viscosity of the semibatch copolymers is lower than that of the corresponding batch ones. The Young's modulus increases for the semibatch copolymers, with increasing PMI content, while a clear trend for the batch copolymers is not found. The tensile strength tends to decrease for both types of copolymers when PMI content increases. The thermal stability increases with increasing PMI content in the copolymers. © 1996 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
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  • 15
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 41 (1990), S. 735-749 
    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: Electrocopolymerization of 3-carboxyphenyl maleimide and styrene onto Hercules AS-4 graphite fiber surfaces has been successfully carried out from an aqueous solution containing monomers and dilute sulfuric acid. Initiation of copolymerization of the monomers dissolved in a small amount of dimethylacetamide is achieved by constant-current electrolysis in the cathodic chamber of a three-compartment electrolysis cell. Polymerization is initiated at the fiber surfaces; little polymer is formed in the cell solution. Electrocopolymerization is very consistent and rapid. The amount of polymer increases predictably with increasing comonomer concentration and current density. Using a 0.4 M (1 : 1) comonomer concentration, 0.0125 M sulfuric acid solution, and a current density of 20 mA/g, more than 60 wt % of copolymer coating per unit weight of graphite fibers is obtained within thirty minutes. Thermal gravimetric analysis showed the copolymer to be very stable at elevated temperatures and has initial and final decomposition temperatures of 430 and 520°C, respectively. The glass transition temperature measurement of the copolymer coatings was carried out by differential scanning calorimetry. A single glass transition temperature was obtained of about 210°C for most samples. The glass transition temperature of the copolymers did not change significantly with changing comonomer feed composition. Functional group and compositional analysis of the copolymer was done by FTIR spectroscopy. The copolymer composition remained relatively the same for copolymers made from different styrene/3-carboxyphenyl maleimide feed composition, confirming a strong tendency toward alternation for the system.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
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  • 16
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 47 (1993), S. 93-104 
    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: Electrochemical copolymerization of styrene and N-(3-carboxyphenyl)maleimide was performed in an aqueous sulfuric acid solution using AS-4 graphite fibers as the working electrode. Cyclic voltammetric analysis results suggest radical initiation of polymerization via the reduction of the N-(3-carboxyphenyl)maleimide and sulfuric acid. Radical chain electrocopolymerization was strongly suggested by the inhibition of chain growth in the presence of hydroquinone and 2,2-diphenylpicrylhydrazyl (DPPH). Compositional analysis of copolymers and reactivity ratios rs ∼ 0.014 and rm ∼ 0.041 for styrene and N-(3-carboxyphenyl)maleimide [N-(3-CMI)], respectively, confirmed a 1 : 1 alternating electrocopolymerization. Kinetic analysis shows a first- and 1/2-order dependence of the rate of chain growth on initial monomer concentration and initiator concentration, respectively. A model incorporating these data is presented. © 1993 John Wiley & Sons, Inc.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
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  • 17
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 59 (1996), S. 1493-1505 
    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 extent of cure for epoxy resin (BADGE) with a small excess of amine hardener (DDM, 4w/o) was determined by assay of the epoxy groups using near infrared spectroscopy. The effect of cure time at 100°C and postcure time at 180°C has been investigated. For the lower temperature cures the room temperature density, ρrt, increased with time, reaching a maximum at Xe = 0.37, and then decreased with extended cure times. For postcure, there was a monotonic decrease in ρrt that was unrelated to the extent of cure. There was an approximate linear relationship between glass transition temperature and In(t), which increased even when essentially all of the epoxy groups had reacted, that is Xe ∼ 0.99. © 1996 John Wiley & Sons, Inc.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 18
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 2491-2508 
    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 diffusion of a disperse dye, 1-amino-4-hydroxyanthraquinone (C.I. Disperse Red 15) into poly(ethylene terephthalate) fibers has been studied as a function of heatsetting temperature and draw ratio. It was found that the dynamic loss modulus E″, measured under the dyeing conditions, was related to the dye diffusivity D. This indicates that the diffusion is controlled by the mobility of the polymer chain segments. Both the diffusivity and dye saturation values do not vary monotonically with heatsetting temperature but exhibit a minimum at a heat-setting temperature near 175°C. X-ray diffraction measurements were used to show that this behavior is attributable to crystallinity and crystal size changes resulting from heat-setting.
    Additional Material: 10 Ill.
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  • 19
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 18 (1974), S. 343-349 
    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.
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  • 20
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 18 (1974), S. 2243-2247 
    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.
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