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  • 1990-1994  (5)
  • 1965-1969  (3)
  • Polymer and Materials Science  (7)
  • Pinaceae  (1)
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Material
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Year
Keywords
  • 1
    Electronic Resource
    Electronic Resource
    The 5S RNA genes inPinus radiata and the spacer region as a probe for relationships betweenPinus species (1992)
    Springer
    Plant systematics and evolution 183 (1992), S. 209-221 
    Details
    ISSN: 1615-6110
    Keywords: Gymnosperms ; Pinaceae ; Pinus radiata ; 5S RNA genes ; spacer variants ; phylogenetic groups
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The 5S RNA genes inPinus radiata occur in two size classes of about 850 and 525 bp in length. Representatives from both the long and short size classes were cloned and sequenced. The primary difference in the two size classes was shown to be a 330 bp insertion in the spacer region of the long units. Within an individual breeding clone ofP. radiata there was some sequence heterogeneity between representatives of the short class. The 5S RNA genes in thirty pine species were characterised using either a clone of the short size class or a subclone of the 330 bp insertion characterizing the long size class. Eleven species of subg.Strobus were examined and all lacked the long type of unit of radiata pine. The New World species of subg.Pinus all had both short and long units whereas the Old World species had long units. The implications of these results for the evolution of the 5S DNA sequences and the phylogenetic relationships withinPinus are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00940804
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  • 2
    Electronic Resource
    Electronic Resource
    Relation between melting behavior and physical structure in polymers (1969)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 7 (1969), S. 1033-1057 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The phenomenon of double melting, as manifested by two characteristic endotherms in the melting region on a differential thermal analysis (DTA) scan, has been studied in nylon 66 and polystyrene as a function of sample treatment by annealing or drawing. A variety of techniques were used in these studies including DTA, x-ray diffraction, electron microscopy, and mechanical testing. It is shown that the two endotherms are not caused by a bimodal crystal size distribution, by recrystallization, by orientation changes, or by phase changes. It is proposed that one endotherm is caused by the melting of foldedchain crystals, while the other is due to the melting of less perfect bundle crystals. This view is well supported by the results, especially by the DTA measurements made at different heating rates. Published data on the thermal behavior of annealed and drawn poly(ethylene terephthalate) and on polyethylene crystallized at various pressures may also be explained on this basis if it is allowed that in polyethylene the chains may be more extended.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1969.160070606
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Rate of electropolymerization of N,N'dimethyl acrylamide in aqueous sulfuric acid solution (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 49 (1993), S. 583-592 
    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: Electropolymerization of N,N-dimethylacrylamide has been performed in aqueous sulfuric acid solution, using unsized AS-4 graphite fibers as the working electrode. The electro-polymerized poly (N,N-dimethylacrylamide) deposited on the surface of the graphite fiber working electrode. The formation of poly (N,N'dimethyl acrylamide) was inhibited by hydroquinone. The addition of about 0.05 moles of hydroquinone to the reaction solution resulted in about a 90% decrease in the weight gain of fibers, in agreement with the proposed free radical mechanism of aqueous electropolymerization. The rate of electropolymerization varied with the initial monomer concentration, current density, and sulfuric acid concerntration, raised to the power of 1.3, 0.42, and 0.07, respectively, that is, Rp ∝ [M]1.3-Cd0.42 [H2SO4]0.07. A mathematical model, based upon free radical polymerization kinetics, is discussed. © 1993 John Wiley & Sons, Inc.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1993.070490404
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  • 4
    Electronic Resource
    Electronic Resource
    Aqueous electropolymerization of polyacrylamide onto AS-4 graphite fibers (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 43 (1991), S. 2237-2247 
    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: 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
    URL: http://dx.doi.org/10.1002/app.1991.070431213
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  • 5
    Electronic Resource
    Electronic Resource
    Multiple melting in nylon 66 (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1773-1781 
    Details
    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
    URL: http://dx.doi.org/10.1002/pol.1968.160061007
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  • 6
    Electronic Resource
    Electronic Resource
    Thermoplastic matrix composites by aqueous electrocopolymerization onto graphite fibers (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 41 (1990), S. 735-749 
    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: 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
    URL: http://dx.doi.org/10.1002/app.1990.070410321
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  • 7
    Electronic Resource
    Electronic Resource
    Mechanism of the electrocopolymerization of styrene and N-(3-carboxyphenyl)maleimide onto graphite fibers in aqueous solution (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 47 (1993), S. 93-104 
    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: 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
    URL: http://dx.doi.org/10.1002/app.1993.070470112
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  • 8
    Electronic Resource
    Electronic Resource
    The effect of structural changes on dye diffusion in poly(ethylene terephthalate) (1968)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 2491-2508 
    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 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1968.070121109
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