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  • 1
    Electronic Resource
    Electronic Resource
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 33 (1993), S. 675-685 
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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 objective this work was to determine the effects of selected polyester catalysts on the reaction of a polyester with epoxy functional polymers. Polyesters containing various catalyst metals were melt blended with either an ethylene-co-glycidyl methacrylate or a styrene-co-glycidyl methacrylate copolymer. The viscosities of the blends were monitored as a function of mixing time using torque rheometry. In addition, the molecular weight distributions of selected samples were analyzed using gel permeation chromatography. Both the torque rheometry and the gel permeation chromatography results indicate that the polyester reacts with epoxy functional polymers. This reaction occurs under conditions and at processing times which are readily obtainable in conventional melt processing equipment. Furthermore, the reaction kinetics of polyesters with glycidyl methacrylate copolymers are dramatically affected by the nature of the catalyst system used to prepare the polyester. Under the conditions used, antimony catalysts are particularly effective at promoting the reaction between polyesters and the epoxy functionality and the activity of the catalysts studied appears to decrease in the following order: antimony 〉 gallium 〉 tin ≃ titanium 〉 germanium. Manipulation of the polyester catalyst system may offer a method to control the extent of reaction obtained in reactive processing of polyesters with epoxy functional compounds.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A series of liquid-crystalline polystyrene derivatives with ω-(4-(4-fluorophenylazo)phenoxy)-alkoxy pendant groups have been synthesized and characterized. Homologues with four or more methylene units in the spacer chain exhibit smectic liquid-crystalline phases, while the homologue with three methylene units forms an amorphous glass. The smectic A-isotropic (SA-I) transition temperatures show a marked odd-even effect as a function of the parity of the spacer chain. This odd-even behaviour is also found in the variation of ΔS/R at the SA-I transition across the series. A marked hysteresis between the transition temperatures determined on heating and the transition temperatures determined on cooling is observed. A molecular interpretation of these phenomena is proposed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 2119-2127 
    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 properties of crosslinked thermosetting resins depend markedly on the completeness of the crosslinking process. Determination of the degree of cure of an unsaturated polyester resin has been studied previously by mechanical, spectroscopic and volume resistivity methods. In this respect the effect of cure time and temperature on the ac dielectric constant and dissipation factor at 1 kc/s and 10 kc/s is considered. The dissipation factor appears to be a most useful parameter for detecting changes in the degree of cure in the later stages of reaction.The electrical properties of the cured resin are discussed, and values for the energy of activation for electrical conduction are compared with literature reports on similar materials.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 34 (1996), S. 1823-1826 
    ISSN: 0887-624X
    Keywords: hybrid inorganic/organic IPN ; porous materials ; poly(styrene) ; silica gel nanotubes ; mesoporous hexagonal silica ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 34 (1996), S. 1543-1552 
    ISSN: 0887-624X
    Keywords: polyester ; polyolefin and blend ; macromonomer and epoxy ; epoxy ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Methods for preparing saturated polyolefin oligomers with Si(SINGLE BOND)H, epoxy groups, and with dihydroxy groups have been developed. Anionic polymerization of butadiene, then termination of the chains with chlorodimethylsilane leads to controlled molecular weight oligomers with silane functionality, and wherein the microstructure can be tailored. Hydrogenation of these materials proceeds smoothly using colloidal nickel catalysts to yield the corresponding saturated materials, which are stable to conditions used for melt polyesterifications. Hydrosilation of allyl glycidyl ether with the Si(SINGLE BOND)H end groups produces epoxy functional oligomers, and subsequent hydrolysis of the epoxy rings yields oligomers with a dihydroxy group at one end. Melt copolymerization of the olefin macromers with 1,4-butanediol and 1,4-dimethylcyclohexanedicarboxylate in the presence of titanium isopropoxide affords poly(ester-g-olefin) graft copolymers. These copolymers are under study as model interfacial agents for polyester/polyolefin blends and as suspension agents for polyester particles in nonpolar media. © 1996 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 36 (1990), S. 1189-1199 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A model for coal thermal depolymerization is described and used to predict molecular weight distributions (MWD) of primary coal pyrolysis liquids. The model assumes that rupture of kinetically similar bonds in the coal is the preferred pathway for release of oligomers which ultimately become tars or extractables. The analysis provides the liquids MWD as a probability function of finding different oligomers composed of whole integer numbers of monomers and it is in excellent qualitative agreement with measured MWDs of coal pyrolysis liquids. The predicted MWDs are of the form of the gamma distribution function (GDF), and its parameters are interpreted in terms of the postulated chemistry of coal thermal depolymerization. Consequently, successful empirical correlations of experimental data on coal pyrolysis liquids MWDs with the GDF are better understood. Thus a protocol is provided to predict MWDs of pyrolysis liquids from knowledge of coal molecular structure.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 15 (1969), S. 47-50 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The evaporation of n-decane into air from the surface of Celite particles, has been used for the establishment of mass transfer factors for both packed and fluidized bed systems. For these calculations log mean partial pressure differences were used. Actual concentration profiles of the transferable component were also experimentally measured by monitoring, at different bed heights, the concentration of n-decane vapor present in air used as the carrier gas. This was made possible through the use of an extremely sensitive hydrocarbon analyzer. The resulting profiles were used to obtain, by graphical integration, the actual driving force prevailing for each run. A nearly one-to-one correspondence was found to exist between the actual driving force and the corresponding log-mean value for both packed and fluidized bed runs.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 28 (1982), S. 759-765 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Overall heat transfer coefficients were measured for an instrumented horizontal tube of diameter 25 mm in the feedboard region above fluidized beds of 102 μm, 470 μm and 890 μm sand in a 0.25 m × 0.43 m × 3.0 m tall pilot scale column. The superficial air velocity varied from near minimum fluidization to 1.7 m/s. The instrumented tube was placed at different positions in a 16-tube bundle. The measured heat transfer coefficients were bounded for tubes near the expanded bed surface by the immersed tube values, and for remote tubes by the values for particle-free air in crossflow. The results are correlated within ± 12% by a simple equation which incorporates these limits. The results are in good qualitative and quantitative agreement with previous experimental results.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 25 (1987), S. 1099-1111 
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The dielectric relaxation behavior of a nonaligned and an aligned liquid-crystalline (LC) polymer are reported for the ranges 10-3.5 to 105 Hz and 274-363 K. Multiple processes (δ and α) are observed that follow a Vogel equation for the temperature dependence related to the apparent glass transition temperature. The occurrence of these processes and the variation in their relaxation strengths as sample alignment is changed is interpreted in terms of a molecular theory for the dielectric behavior of a LC polymer that involves the director order parameter Sd, the mesophase order parameter S, the dipole moment components of the mesogenic head groups, and their associated relaxation functions.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 36 (1995), S. 227-237 
    ISSN: 0959-8103
    Keywords: copolymerization ; 1-vinyl-2-pyrrolidone ; acrylic acid ; H-complex relative reactivity ; 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 dimerization constant (Kg) of acrylic acid and the association constant of the comonomer complex between acrylic acid and 1-vinyl-2-pyrrolidone (K1) have been determined in chloroform by means of IR and 1H NMR spectroscopy: Kd=(2.0±0.2) × 103litre mol-1 and K1=68.5±0.5 litre mol-1. A detailed equation for the copolymer composition considering the participation of the intermolecular complexes in the chain propagation has been derived with the help of a specific regular three addition states Markov chain. Applying a numerical procedure for fitting the experimental curve for the comonomer composition, this equation has been used in the estimation of the dimer and the comonomer complex relative reactivities. The considerably higher reactivities of the two complexes compared with that of the monomers are accounted for by the π-electrons' greater delocalization in the transition states involving the complexes species.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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