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  • 1
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 3-Methyl-1-butene (3M1B) was found to undergo monomer-isomerization copolymerization with 2-pentene (2P) in the presence of Ziegler-Natta catalyst to give a copolymer exclusively consisting of 3M1B and 1-pentene (1P) units, the same as that obtained from copolymerization of 3M1B and 1P. The apparent copolymerization parameters were determined. The amount of 3M1B unit incorporated in the copolymers was found to increase in the copolymerization system of 3M1B-2P more than in that of 3M1B-1P. The polymers consisting of nearly complete 3M1B units were produced at a rapid rate through monomer-isomerization copolymerization of 3M1B with 2P in the presence of TiCl3 - (C2H5)3Al catalyst.
    Additional Material: 2 Ill.
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  • 2
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Nylons containing carbonyl groups in backbone chains were prepared and their response to heat was studied. The carbonyl groups were introduced using either HOOC(CH2)4CO(CH2)4COOH or H2N(CH2)5CO(CH2)5NH2 in the initial monomer compositions. In addition to pyrolysis of these polyamides, the progress of chemical and physical changes as a function of temperature was continuously monitored and analyzed by FT-IR spectroscopy on cast films placed in an environmental chamber. Introduction of the carbonyl groups into the polymer backbone resulted in a significant reduction of the thermal stability of the corresponding polyamide. Possible mechanisms for the thermal degradation entailing these carbonyl groups and N-acylamide compounds are discussed.
    Additional Material: 14 Ill.
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  • 3
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The isomerization and polymerization of propenylbenzene (PB) with various Ziegler-Natta catalyst systems have been investigated. With the TiCl3-(C2H5)3Al (Al/Ti 〉 2.0) catalyst at 80°C, PB polymerized to give a polymer exclusively consisting of allylbenzene (AB) unit. During the polymerization, AB, which polymerized readily with the catalyst, was produced through isomerization of PB, indicating that PB underwent monomer-isomerization polymerization. PB also polymerized with isomerization to AB in the presence of TiCl3-(C2H5)2AlCl-NiCl2 catalyst system, and a copolymer with PB and AB units was obtained. With TiCl3-C2H5AlCl2 catalyst, poly(PB) was formed via ordinary vinylene polymerization without isomerization. From these facts, it was concluded that the structure of the polymers produced from PB widely changed, depending on the catalyst systems used, which determine the rate of isomerization to AB and the polymerization reactivity of the PB and AB isomers formed.
    Additional Material: 3 Ill.
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  • 4
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Addition reactions of pendant epoxide groups in poly(glycidyl methacrylate) (PGMA) with various active esters such as 1-benzotriazolyl benzoate, S-(2-benzoxazolyl) thiobenzoate, S-(2-benzothiazolyl) thiobenzoate, 4-nitrophenyl benzoate (4NPB), and S-phenyl thiobenzoate (PTB) were carried out using quaternary salts as catalysts. The reactions of PGMA with those active esters proceeded in diglyme at 100°C for 24 h quantitatively without the formation of 2-hydroxyl pendant groups in the polymer when 10 mol % of tetraethylammonium bromide was used as a catalyst. Furthermore, it was found that the respective quaternary salts have higher catalytic activity than tertiary amines in the reaction of PGMA with the active esters, and the reaction of PGMA with 4NPB gave the corresponding polymer with the highest conversion by addition of tetrabutylammonium bromide as a catalyst, while tetraethylammonium chloride showed the highest activity for the reaction of PGMA with PTB. In addition, the rate of reaction of PGMA with 4NPB was proportional to third order kinetics of the epoxide concentration, the ester concentration and the catalyst concentration as follows: -d[Epoxide]/dt = -[Ester]/dt = k3[Epoxide] [Ester] [Catalyst].
    Additional Material: 5 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new class of poly-conjugated polymers has been obtained by condensation of anthraquinones with aromatic diamines in polyphosphoric acid. The polymers are black, intractable powders. Toward obtaining tractable materials, the effect of monomer structure on polymer tractability has been studied. Copolymerizations were also carried out to “soften” these materials. Electrical conductivities in the semiconducting range, 10-4- 10-8 (ohm cm)-1 were observed. Doping with iodine showed small increases.
    Additional Material: 1 Ill.
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  • 6
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Tab.
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  • 7
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A systematic study of the thermal polymerization of α-chloroacrylic acid and α-bromoacrylic acid in aqueous nitric acid was carried out. The effect of variation of monomer concentration lead tetraacetate concentration, hydrogen ion concentration, ionic strength, and temperature on the rate of monomer disappearance was carried out. Based on the experimental observations, suitable reaction schemes were proposed for the polymerization of the above monomers. The rate constants and the thermodynamic parameters were evaluated.
    Additional Material: 1 Ill.
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  • 8
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The nucleophilic substitution of the chlorine atoms of poly(vinyl chloride) with sodium thiophenate is assumed to obey an SN2 mechanism with inversion of configuration and a steric control according to which reactivities R of the triads follow the order Rmm 〉 Rmr ≫ Rrr. Such a reaction cannot be described by simple differential equations, but a Monte Carlo simulation, first generating a random Bernouillian chain and then simulating random attack of the chain by the reactant according to the triad reactivities, allows a good agreement with the experimental results of both the kinetics of a reaction carried out in cyclohexanone solution at 40°C and the evolution of the 13C and 1H NMR spectra of the tertiary carbon atoms, assuming the following parameters: Bernouillian probability for a meso placement in the initial chain: 0.431; relative reactivities of the mm, mr and rm, rr triads: 1, 0.5, and 0., respectively. The agreement is excellent until the reaction is about three-quarters complete; this shows a limiting level of about 60% substitution. Better agreement can be obtained up to the limit, if a secondary process of steric control by the substituant in a partially substituted mr triad is assumed. Other possibilities for that secondary process are discussed.
    Additional Material: 21 Ill.
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  • 9
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Mn, Mw and PD = Mw/Mn of polypropylene obtained with the MgCl2/ethyl benzoate/p-cresol/AlEt3/TiCl4-AlEt3/methyl-p-toluate (CW-catalyst) have been obtained as a function of temperature, monomer, and AlEt3 concentrations. The values of Mn after a few minutes of polymerization range from 50% to 100% of the final values. I.I. (percent yield of stereoregular polymer) and P.D. of stereoregular polymer remain constant during a batch polymerization. The MW distribution is very narrow with PD ⋍ 2.0 between 0° and 50° using optimum A/T ratio. It is broader for polymerizations employing low or high A/T ratio or elevated temperature, reaching P.D. = 2.78 at 70°C. The corresponding P.D. values for the total polymer ranged from 3.1 to 4.5 due to contributions from the heptane soluble fraction. The latter gives bimodal GPC chromatogram. The Mn of stereoregular polymer is much smaller than the reciprocal of concentration of metal polymer bonds, [MPB]-1; the ratio of the two quantities is a measure of number of polymer chains not bonded to a metal ion to the number of those which are bonded to either Ti or Al. Depending upon the experimental conditions, this ratio varied from 2.3 to 23.5 for short polymerization time, and 16 to 31 for long polymerization time.Chain transfer with AlEt3 is ineffective for the CW-catalyst system. From the plots of [MPB] versus yield, the rate constants for this process obtained at 50° are: ktr1iA = 2.1 × 10-4 sec-1; ktr1aA = 2 × 10-5 sec-1; ktr2iA = 1.1 × 10-4 sec-1; and ktr2aA = 1.2 × 10-5 sec-1 where the subscripts i, a, 1 and 2 refer to stereospecific and nonstereospecific sites of first and second kind respectively. Thr transfer rates increase with both increasing and decreasing temperatures consistent with the Langmuir-Hirschelwood adsorption model.The MW of isotactic polymers are dependent upon monomer concentration. The chain transfer with monomer has rate constants at 50° of ktr1iM = 1.34 × 10-2 M-1 sec-1 and ktr2iM = 1.2 × 10-3 M-1 sec-1. In addition there is chain transfer by β-hydride elimination with ktr,iβ = 2.7 × 10-2 sec-1 at 50° which is the chain lifetime limiting process at low monomer concentration. The rate of chain transfer with monomer can exceed that of β-hydride elimination at high propylene pressure.The very narrow PD for the stereoregular polymers suggest there is only one chemically distinct isospecific active site.
    Additional Material: 15 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Fluorescence analysis has been employed as an analytical technique to elucidate the photolysis mechanism of several aromatic diisocyanate-based polyurethanes in solution. Based on a comparison with model arylmonocarbamates and arylbiscarbamates, the photo-Fries rearrangement and cleavage-type products found for the small-model arylcarbamates were also identified for the photolyzed polyurethanes in solution. Viscosity and absorbance change results for photolysis of both air and nitrogen-saturated polyurethane solutions are consistent with a general two-step mechanism for the photolysis of aromatic diisocyanate-based polyurethanes.
    Additional Material: 13 Ill.
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