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  • 1
    Electronic Resource
    Electronic Resource
    Initiation via Haloboration in Living Cationic Polymerization. 1. The Polymerization of Isobutylene (1994)
    s.l. : American Chemical Society
    Macromolecules 27 (1994), S. 3453-3458 
    Details
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ma00091a002
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  • 2
    Electronic Resource
    Electronic Resource
    Conjugated Ionic Polyacetylenes. 9. Polymerization of N-methyl-2-ethynylpyridinium Trifluoromethanesulfonate in Aprotic Polar Solvents (1995)
    s.l. : American Chemical Society
    Macromolecules 28 (1995), S. 5691-5698 
    Details
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ma00121a001
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  • 3
    Electronic Resource
    Electronic Resource
    Initiation via Haloboration in Living Cationic Polymerization. 2. Kinetic and Mechanistic Studies of Isobutylene Polymerization (1994)
    s.l. : American Chemical Society
    Macromolecules 27 (1994), S. 4648-4651 
    Details
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ma00095a002
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  • 4
    Electronic Resource
    Electronic Resource
    Conjugated Ionic Polyacetylenes. 7. Oligomerization of N-Methyl-2-ethynylpyridinium (Trifluoromethyl)sulfonate in Methanol and Pyridine (1995)
    s.l. : American Chemical Society
    Macromolecules 28 (1995), S. 25-33 
    Details
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ma00105a004
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  • 5
    Electronic Resource
    Electronic Resource
    Enhancement of laser-induced optical breakdown using metal/dendrimer nanocomposites (2002)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 80 (2002), S. 1713-1715 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We demonstrate that dendrimer nanocomposites (DNC) can be used to remarkably change the laser-induced optical breakdown (LIOB) threshold of a material, owing to a large enhancement of the local electric field. We have implemented LIOB using femtosecond laser pulses in a gold/dendrimer hybrid nanocomposite as a model system. Third-harmonic generation measurements have been employed as a sensitive way for monitoring the LIOB in situ and in real time. The observed statistical behavior of the breakdown process is attributed to a laser-driven aggregation of individual DNC particles. The breakdown threshold value of the DNC has been found to be up to two orders of magnitude lower than that of pure dendrimers or normal tissues. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1459483
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  • 6
    Electronic Resource
    Electronic Resource
    Direct monitoring of cationic polymerization by temperature, conductivity and permittivity measurements (1990)
    Springer
    Polymer bulletin 23 (1990), S. 75-82 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Direct monitoring of cationic polymerization was accomplished by simultaneous measurement of the average dielectric constant, representing the dipoles, of the conductivity, produced by unpaired ions, and of the temperature, characteristic for reaction rate. The ionogenic equilibria during the living polymerization of isobutylene by 1, 3, 5-tris(2-methoxy-2-propyl)benzen/BCl3 in CH2Cl2 at-25°C were demonstrated. Temperature, resistance and capacitance were measured directly in the reaction mixture by a specially designed instrument. Both the conductivity and the average dielectric constant change characteristically during the living polymerization, indicating the presence and simultaneous change of unpaired ions and strongly polarized species. The differences between the AMI, and the aging technique were demonstrated and explained. In the latter case slow initiation was observed due to the methoxy-chlorine exchange caused by a reaction with BCl3. The applied direct monitoring method helps to understand the role of polarized and ionic species in polymerizations and related processes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00983967
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  • 7
    Electronic Resource
    Electronic Resource
    Living carbocationic polymerization of isobutylene with BCl3 coinitiation in the presence of di-tert-butylpyridine as proton trap (1992)
    Springer
    Polymer bulletin 28 (1992), S. 367-374 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The living polymerization of isobutylene (IB) has been achieved with the 2,4,4-trimethylpentyl chloride (TMPCl) or cumyl chloride (CumCl)/BCl3/(IB)/methyl chloride/-40°C system in the presence of proton trap 2,6-di-tert-butylpyridine (DTBP) in concentrations comparable to that of protic impurities. According to kinetic studies the polymerization is first order both in respect to monomer and BCl3. The polymerization rate is not effected by the excess DTBP which suggests that the livingness is not due to carbocation stabilization. Comparison of the results in the presence of DTBP and/or dimethyl sulfoxide (DMSO) demonstrated that the main function of the electron donor (ED) DMSO is to trap protic impurities. The assumption of carbocation stabilization is unnecessary, and reversible termination and the absence of chain transfer is sufficient to explain livingness. In the absence of proton trap or ED however, fast polymerization by the protic impurities occurs masking the much slower living polymerization and the monomer is consumed mainly by this process unless the protic impurities are scavenged.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00297327
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  • 8
    Electronic Resource
    Electronic Resource
    Investigation of 1,3,5-tris(2-metoxypropane)benzene/BCl3 initiated living isobutylene polymerization by C13 and B11 NMR spectroscopy (1990)
    Springer
    Polymer bulletin 23 (1990), S. 335-340 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The living carbocationic polymerization of isobutylene initiated by 1,3,5-tris(2-methoxypropane) benzene (TriCumOMe)/BCl3 system was investigated by C13 and B11 NMR spectroscopy. The reaction between the TriCumOMe and BCl3 at-30°C in CH2Cl2 after 15 mins reaction time resulted in 1,3,5-tris(2-chloropropane) benzene (TriCumCl) and methyl-dichloroboronite (BCl2OMe). The same system in the presence of isobutylene yielded three-arm star, chlorine terminated telechelic polyisobutylene and BCl2OMe. No counterions, i.e., BCl3OMe⊝, BCl 4 ⊝ , or neutral boron complexes, e.g., TriCumOMe, 3BCl3 could be detected. The simultaneous measurement of static permittivity (direct monitoring method) showed different reaction rate patterns in the case of AMI method, and when the TriCumOMe+BCl3 mixture was aged and the polymerization was started by isobutylene.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01032450
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  • 9
    Electronic Resource
    Electronic Resource
    Formation of Silver and Gold Dendrimer Nanocomposites (1999)
    Springer
    Journal of nanoparticle research 1 (1999), S. 353-368 
    Details
    ISSN: 1572-896X
    Keywords: dendrimers ; nanoparticles ; polymer-inorganic nanocomposites ; templates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics , Technology
    Notes: Abstract Structural types of dendrimer nanocomposites have been studied and the respective formation mechanisms have been described, with illustration of nanocomposites formed from poly(amidoamine) PAMAM dendrimers and zerovalent metals, such as gold and silver. Structure of {(Au(0))n−PAMAM} and {(Ag(0))n−PAMAM} gold and silver dendrimer nanocomposites was found to be the function of the dendrimer structure and surface groups as well as the formation mechanism and the chemistry involved. Three different types of single nanocomposite architectures have been identified, such as internal (‘I’), external (‘E’) and mixed (‘M’) type nanocomposites. Both the organic and inorganic phase could form nanosized pseudo-continuous phases while the other components are dispersed at the molecular or atomic level either in the interior or on the surface of the template/container. Single units of these nanocomposites may be used as building blocks in the synthesis of nanostructured materials.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1010060404024
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  • 10
    Electronic Resource
    Electronic Resource
    Synthesis, homopolymerization, and block copolymerization of N-ethyl-2-ethynyl-pyridinium trifluoromethanesulfonate with styrene and butadiene (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 703-712 
    Details
    ISSN: 0887-624X
    Keywords: synthesis ; homopolymerization ; block copolymerization ; N-ethyl-2-ethyl-pyridinium ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A novel acetylenic monomer 2-N-ethyl pyridinium trifluoromethane sulfonate (2EPyEtTf) was synthesized and polymerized. Diblock copolymers of 2EPyEtTf with styrene and with butadiene were prepared. Initiation of the polymerization by living anionic polystyryl--Li+ and polybutadienyl--Li+ (Scheme 1) resulted in polystyrene-block-poly(N-ethyl-2-ethynylpyridinium trifluoromethanesulfonate) (PS57PA8), and polybutadiene -block-poly(N-ethyl-2-ethynylpyridinium trifluoromethanesulfonate) (PB30PA8). These amphiphilic block molecules contain rigid, conjugated, and strongly hydrophilic polyacetylene chain fragments attached to hydrophobic polystyrene or flexible polybutadiene chain fragments. The structure of these copolymers was studied by FTIR, UV-visible, and NMR spectroscopy. GPC and viscometry were also used to obtain information on the molecular mass and the molecular mass distribution. Thermal behavior was investigated by means of TGA and DSC. Both block copolymers were shown to form stable monolayers at the air-water interface. The positively charged rigid polyacetylene portion of the copolymer is believed to be partially submerged, while the more flexible hydrophobic chains are forced out of the water. Multilayers of PB30PA8 deposited using the Langmuir-Blodgett technique were found to be less uniform than in the case of the previously reported polystyrene-block-poly(2EPyMeTf) (PS12PA4) copolymer (Balogh et al., Macromolecules, 29, 1996). Polycation-polyanion self-assembly deposition was also investigated, using polystyrenesulfonate (PSS) as polyanion. While PS57PA8/PSS layer-by-layer deposition was not uniform, it was found that PB30PA8/PSS gave homogenous and stable films on hydrophilic glass substrates. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 703-712, 1998
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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