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  • Articles  (8)
  • anionic polymerization  (8)
  • Wiley-Blackwell  (8)
  • American Chemical Society
  • American Physical Society (APS)
  • Blackwell Science Inc
  • Canadian Science Publishing
  • Oxford University Press
  • Sage Publications
  • Soil Science Society of America
  • 2020-2024
  • 2005-2009
  • 1990-1994  (8)
  • 2021
  • 2009
  • 2005
  • 1994  (8)
  • Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics  (8)
  • Energy, Environment Protection, Nuclear Power Engineering
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  • Articles  (8)
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  • Wiley-Blackwell  (8)
  • American Chemical Society
  • American Physical Society (APS)
  • Blackwell Science Inc
  • Canadian Science Publishing
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  • 2020-2024
  • 2005-2009
  • 1990-1994  (8)
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  • 2021
  • 2009
  • 2005
  • 1994  (8)
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  • Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics  (8)
  • Energy, Environment Protection, Nuclear Power Engineering
  • Chemistry and Pharmacology  (10)
  • Physics  (8)
  • 1
    Electronic Resource
    Electronic Resource
    Methacrylate-based block ionomers I: Synthesis of block ionomers derived from t-butyl methacrylate and alkyl methacrylatesDedicated to Professor Maurice Morton to commemorate the establishment of the Maurice Morton Institute of Polymer Science at the University of Akron. (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 33 (1994), S. 205-216 
    Details
    ISSN: 0959-8103
    Keywords: block ionomer ; anionic polymerization ; methacrylates ; 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: Diblock and triblock copolymers of t-butyl methacrylate (tBMA) with 2-ethylhexyl methacrylate (EHMA) and n-hexyl methacrylate were prepared via alkyl lithium initiation and sequential addition techniques in THF at -78°C. The tBMA blocks were quantiatively and selectively hydrolyzed to afford poly(methacrylic acid) (PMAA) blocks which were then neutralized with alkali metal bases to form block ionomers. The unhydrolyzed copolymers had a phase mixed morphology as evidenced by thermal analysis while the hydrolyzed and neutralized polymers were multiphase materials. The carboxylic acid and ioncontaning triblock copolymers formed gels in nonpolar solvents which could be disrupted by the addition of polar additives. Certain carboxylic acid and ioncontaining EHMA/tBMA diblock copolymers also showed this behavior. The triblock ionomers did not show thermoplastic flow prior to degradation, except at the lowest ionic content studied (2%).
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pi.1994.210330212
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  • 2
    Electronic Resource
    Electronic Resource
    Anionic polymerization of octamethylcyclotetrasiloxane in aqueous emulsion I: Preliminary results and kinetic study (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 35 (1994), S. 179-188 
    Details
    ISSN: 0959-8103
    Keywords: anionic polymerization ; octamethylcyclotetrasiloxane ; emulsion ; α,ω-dihydroxy polydimethylsiloxane ; 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 synthesis of poly(dimethylsiloxane) (PDMS) by anionic polymerization of octamethylcyclotetrasiloxane (D4) in aqueous emulsion using an emulsifying agent acting also as initiator (benzyldimethyldodecylammonium hydroxide) is described. Stable emulsions of α,ω-dihydroxy PDMS with an easily controlled molar mass (up to 15 000), a low polydispersity index and high yields were obtained. The amount of cyclics formed (essentially D4 to D7) is lower than that observed in bulk. Kinetics analysis and computerized simulations are in good agreement with a reaction scheme involving simultaneous polyaddition/polycondensation processes. At high monomer consumption, polycondensation predominates leading to a broadening of the molecular weight distribution (MWD). The apparent rate constants of initiation, propagation and condensation at various temperatures and the corresponding activation energies were determined.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pi.1994.210350208
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  • 3
    Electronic Resource
    Electronic Resource
    A hydrocarbon-soluble difunctional orgaolithium anionic initiator. Synthesis of 2,2-bis[3-(1-lithio-2,3-dimethylpentyl)-4-methoxyphenyl]propane (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 34 (1994), S. 163-171 
    Details
    ISSN: 0959-8103
    Keywords: anionic polymerization ; 2,2-bis[3-(1-propenyl)-4-methoxyphenyl]-propane ; difunctional initiator ; organolithium ; intramolecular ether linkage ; nonpolar solvents ; 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 reaction of stoichiometric amounts of sec-butyllithium with 2,2-bis[3-(1-propenyl)-4-methoxyphenyl]propane (4) produces a new difunctional organolithium initiator, 2,2-bis[3-(1-lithio-2,3-dimethylpentyl)-4-methoxyphenyl] propane, which is soluble in hydrocarbon solvent in the absence of any polar additive. Following isolation and purification by gas liquid chromatography, the structures of (4) and the methanolysis product of the difunctional initiator were characterized by 1H NMR, FTIR and mass spectroscopy and elemental analysis. The dilithium initiator is effective for the polymerization of 1,3-butadiene and allows the preparation of polybutadienes with predictable molecular weights, narrow, monomodal molecular weight distribution and low 1,2-diene microstructure.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pi.1994.210340207
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  • 4
    Electronic Resource
    Electronic Resource
    Effect of addition of organoaluminum and organoboron compounds in the stereospecific polymerization of acrylonitrile using dialkylmagnesium as catalyst (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 34 (1994), S. 397-405 
    Details
    ISSN: 0959-8103
    Keywords: stereospecific polymerization ; polyacrylonitrile ; tacticity ; dialkylmagnesium ; alkylaluminum ; additive ; anionic polymerization ; 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: An attempt was made to clarify the effect of addition of organoaluminum and organoboron compounds in the stereospecific polymerization of acrylonitrile (AN) initiated by dialkylmagnesium (R2Mg) above 100°C. The triad isotacticity (i.e. the content of mm (m: meso)) as well as the viscosity-average molecular weight (M̄v) of polyacrylonitrile (PAN) increased when trialkylaluminum (R3Al) and trialkylboron (R3B) were used as additives. Diisobutylaluminum hydride [(i-C4H9)2AlH] was found to be the best additive. in the stereospecific polymerization of AN, giving PAN with higher (mm) content (0.63), higher M̄v value (5.2 × 104), and a yield approximately double that obtained using (n-C6H13)2Mg alone. When the (n-C6H13)2Mg/(i-C4H9)2AlH system was used, the yield, (mm), and M̄v of PAN increased with polymerization temperature (Tp); maximum values of yield, (mm), and M̄v were obtained at c. 130°C. The optimum amount of additives was approximately equimolar to R2Mg as initiator. The 13C chemical shift of α-carbon in R2Mg at 90°C shifted by mixing with R3Al and R3B, respectively, indicating the existence of interaction between R2Mg and the additives. The main role of the additives is considered to be suppression of the self-association of R2Mg by strong interaction with R2Mg.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pi.1994.210340408
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  • 5
    Electronic Resource
    Electronic Resource
    Hydrocarbon-soluble difunctional organolithium anionic initiators. A gas-liquid chromatographic study of the reaction of sec-butyllithium with m-divinylbenzene (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 35 (1994), S. 263-272 
    Details
    ISSN: 0959-8103
    Keywords: anionic polymerization ; 1,3-bis(1-lithio-3-methylpentyl)benzene ; gas-liquid chromatography ; high purity sec-butyllithium ; difunctional initiator ; nonpolar solvents ; 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: Quantitative gas-liquid chromatography provides an efficient, novel technique for the kinetic study of the reaction between sec-butyllithium and m-divinylbenzene. The reaction of stoichiometric amounts of ultra-high purity sec-butyllithium with pure m-divinylbenzene at -23°C produces an anionic initiator, 1,3-bis(1-lithio-3-methylpentyl)benzene, 2, without traces of monofunctional and polyfunctional impurities. The relative rates of formation of 2 with and without the presence of Lewis base, triethylamine, or Lewis acid, diethylzinc, were studied by gas-liquid chromatography. The presence of diethylzinc reduces the activity of sec-butyllithium to such an extent that the reaction did not proceed beyond the monofunctional component stage, that is, the formation of m-1-lithio-3-methylpentylvinylbenzene, 1. The reaction of sec-butyllithium with m-divinylbenzene at -79°C with a 10mol% ratio of triethylamine to sec-butyllithium yielded a homogeneous product with composition of 94% difunctionality and 6% monofunctionality, with the total disappearance of m-divinylbenzene as observed by GLC. However, precipitation due to agglomeration was observed at 25°C at 100% conversion.The high purity 1,3-bis(1-lithio-3-methylpentyl)benzene initiator, 2, is effective for the polymerization of 1,3-butadiene and allows the synthesis of polybutadienes with predictable molecular weights and narrow molecular weight distributions. Depending on the polymerization solvent, polybutadienes with microstructures ranging from 9 to 13% 1,2-vinyl content were observed by 1H NMR analysis and FTIR spectroscopy. However, the presence of diethylzinc retards the rate of polymerization of 1,3-butadiene, without any change in polymer microstructure. Triethylamine enhances the rate of 1,2-enchainment without significant reduction in the 1,4-enchainment of polybutadiene.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pi.1994.210350308
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  • 6
    Electronic Resource
    Electronic Resource
    Synthesis of highly isotactic (mm 〉 0.70) polyacrylonitrile by anionic polymerization using diethylberyllium as a main initiator (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 35 (1994), S. 207-213 
    Details
    ISSN: 0959-8103
    Keywords: stereospecific polymerization ; polyacrylonitrile ; tacticity ; diethylberyllium ; additive ; anionic polymerization ; 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: An attempt was made to synthesize steroregular polyacrylonitrile (PAN) with a high triad isotacticity (i.e. the content of mm (m, meso)) exceeding 0.70 by the anionic polymerization method. In the stereospecific polymerization of acrylonitrile (AN) initiated by diethylberyllium (Et2Be) in xylene at 130°C, the (mm) content as well as the viscosity-average molecular weight (MÞv) of PAN increased by addition of diisobutylaluminum hydride (i-C4H9)2AlH) as an additive to the polymerization system. Maximum (mm) content, attained in the molar ratio region of (i-C4H9)2AlH/Et2Be 〉 1.0, was about 0.73. The stereospecific polymerization of AN was also initiated using a mixture of Et2Be and di-n-hexylamagnesium ((Et2Be/(n-C6H13)2 Mg system), where both Et2Be and (n-C6H13)2 Mg can induce the stereospecific polymerization of AN at 130°C. The (mm) content of the PAN sample prepared using the Et2Be/(n-C6H13)2 Mg system ((mm) = 0.64) was higher than that of PAN samples synthesized using Et2Be alone ((mm) = 0.56) and (n-C6H13)2Mg alone ((mm) = 0.51) under the same conditions except initiator. A significant difference in 13C chemical shifts of α-carbons between Et2Be (1.35 ppm) and (n-C6H13)2Mg (10.72 ppm) dissolved in hydrocarbon solvent at 110°C leads us to the conclusion that when Et2Be induces the stereospecific polymerization in the Et2Be/(n-C6H13)2Mg system as initiator, the main role of (n-C6H13)2Mg is considered to be the suppression of the association of Et2Be (active site) itself.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pi.1994.210350211
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  • 7
    Electronic Resource
    Electronic Resource
    Anionic synthesis and characterization of ω-formyl-functionalized polystyrenesDedicated to Professor Maurice Morton to commemorate the establishment of the Maurice Morton Institute of Polymer Science at the University of Akron. (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 33 (1994), S. 181-186 
    Details
    ISSN: 0959-8103
    Keywords: anionic polymerization ; functionalization ; aldehyde functional group ; 4-morpholinecarboxaldehyde ; diphenylphosphonic chloride ; 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: ω-Formyl-functionalized polystyrenes can be synthesized in quantitative yield by reacting poly(styryl)lithium (Mn = 2 × 103-8 × 103 g/mol) in benzene with a 0.1-0.4 molar excess of 4-morpholinecarboxaldehyde followed by methanol termination and precipitation into methanol. Narrow molecular weight distribution ω-formyl-functionalized polystyrenes were characterized by hydroxylamine end-group titration, thin layer chromatography and both 1H and 13C NMR spectroscopy. The mechanism of the functionalization was studied by trapping the tetrahedral α-amino alkoxide intermediate with diphenylphosphinic chloride.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pi.1994.210330209
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  • 8
    Electronic Resource
    Electronic Resource
    Some light on the concept of unreactivity arising from active center association in anionic polymerizationsDedicated to Professor Maurice Morton to commemorate the establishment of the Maurice Morton Institute of Polymer Science at the University of Akron. (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 33 (1994), S. 217-231 
    Details
    ISSN: 0959-8103
    Keywords: organolithium ; anionic polymerization ; propagation reaction orders ; 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 long held assumption in hydrocarbon based anionic polymerization involving organolithiums is that the aggregated species are unreactive and thus serve only as reservoirs from which the active singlet species momentarily emerge to participate in the initiation or propagation events. This work demonstrates that contrary to the notion of aggregate dormancy such species can participate in monomer addition. The approach involved freeze-dried vitrified polystyryllithium which was found to be reactive toward butadiene and methanol vapors. The sub-glass transition state of the polystyryllithium eliminates the establishment of the aggregate: singlet equilibrium as a result of the inability of chains to undergo diffusion. Furthermore, it is shown that the lower bound gradient for the dependence of propagation rate on active center concentration, within experimental error, is about 1/5 for the majority of those diene systems where the active center concentration covers at least two decades. A computer evaluation of the propagation rate: active center data was done with the aim of testing and determining the equilibrium constants of these aggregated systems.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pi.1994.210330213
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