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  • 1
    Electronic Resource
    Electronic Resource
    Aggregation of syndiotactic poly(methyl methacrylate) in dilute solutions (1984)
    s.l. : American Chemical Society
    Macromolecules 17 (1984), S. 825-837 
    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/ma00134a051
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  • 2
    Electronic Resource
    Electronic Resource
    Characterization of the stereochemical structure of poly(tert-butyl acrylate) by one- and two-dimensional NMR spectroscopy (1993)
    s.l. : American Chemical Society
    Macromolecules 26 (1993), S. 102-106 
    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/ma00053a015
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  • 3
    Electronic Resource
    Electronic Resource
    1H-NMR study of interactions of dimethyl ester of 2,2,4,4-tetramethylglutaric acid with stereoregular poly(methyl methacrylates) in solution (1982)
    Springer
    Polymer bulletin 8 (1982), S. 171-177 
    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 Studies of integrated band intensities in high resolution (HR) 1H NMR spectra of the dimethyl ester of 2,2,4,4-tetra-methylglutaric acid (DMTMGA) in solutions containing stereo-regular poly(methyl methacrylate)(PMMA) have shown that a part of the DMTMGA molecules interact with PMMA. In this interaction DMTMGA behaves similarly as syndiotactic (s) PMMA. DMTMGA can link-up in self-aggregates of s-PMMA, and also replace s-PMMA in interaction with isotactic (i) PMMA forming an analog of the PMMA stereocomplex. An analogy of the conformational structure of DMTMGA and of the s-sequences in the aggregates of PMMA is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00263024
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  • 4
    Electronic Resource
    Electronic Resource
    Effect of PVC on low-polar isobutylene polymerization in the presence of BCl3 (1996)
    Springer
    Polymer bulletin 36 (1996), S. 557-562 
    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 low-polar polymerization of isobutylene (IB) in the presence of BCI3 was carried out in CH2Cl2 ([IB]=7 mol/l) at -78, -20 and +20°C in the presence of vinyl chloride/2-chloropropene (VC/2CP) copolymer, representing PVC resin enriched in structures with chlorine atoms bonded to the tertiary carbons. The polymerization products consist of mixtures of polyisobutylenes (PIB) and grafted VC/2CP-g-PIB copolymer. Attention was focused on evaluation of the extent of the grafting reaction. VC/2CP-g-PIB was analyzed by GPC, 1H-NMR and 13C-NMR spectroscopies and elemental analysis. The results obtained indicate that the rate of polymerization of IB decreases with increasing temperature but that the grafting efficiency increases. The experiments demonstrated that the VC/2CP copolymer induces strong grafting, compared with PVC, and that it might therefore be assumed that the C-Cl bonds with chlorine atoms bound to tertiary carbons directly initiate the polymerization of IB. The effect of the C-Cl bonds is discussed in terms of their catalytic and initiation activities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00342446
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  • 5
    Electronic Resource
    Electronic Resource
    Effect of PVC on low-polar isobutylene polymerization in the presence of BCl3 (1995)
    Springer
    Polymer bulletin 34 (1995), S. 183-189 
    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 isobutylene polymerizations in the presence of BCl3 were carried out in dichloromethane ([M]=7 mol/l) at-20°C in the presence and absence of PVC. The products of polymerizations in the absence of PVC are oligoisobutylenes with a narrow molecular weight distribution $${\text{(}}\mathop M\limits^{\_\_\_} _{\text{W}} /\mathop M\limits^{\_\_\_} _{\text{n}} \approx {\text{1}}{\text{.3, }}\mathop M\limits^{\_\_\_} _{\text{n}} \approx {\text{2700)}}$$ ; their structure was analyzed by 1H-NMR spectroscopy. In addition to the signals assigned to known unsaturated terminal structures [δ 4.62 and 4.82-CH2C(CH3)=CH2, 5.12-CH=C(CH3)2], a new intense signal was found at δ 5.09 ppm and assigned to the structure-CH=C(CH3)CH2CH3. A mixture of isobutylene homopolymers $${\text{(}}\mathop M\limits^{\_\_\_} _{\text{n}} \approx {\text{2700, 15000)}}$$ and PVC grafted with isobutylene (approx. 9.5% wt. isobutylene grafted) is formed in the presence of PVC.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00316394
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  • 6
    Electronic Resource
    Electronic Resource
    NMR-study of structure and dynamics of associates of syndiotactic poly(methyl methacrylate) in toluene (1980)
    Springer
    Polymer bulletin 2 (1980), S. 227-233 
    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 High-resolution 1H NMR spectra (1H HR-NMR) of solutions of isotactic (i) and syndiotactic (s) poly(methyl methacrylate) (PMMA) in toluene-d8 were measured in the concentration range 0.2 to 10% w/v; for solutions of s-PMMA (10% w/v), 1H NMR spectra with magic angle rotation (MAR-NMR) at various temperatures and 13C NMR spectra with strong proton decoupling were also measured. It was found that even in very dilute solutions of s-PMMA in toluene-d8 a considerable portion (76%) of polymer segments are associated: association is of intramolecular origin and is due to interaction of long syndiotactic sequences. Prom NMR spectra the motion of associated segments appears as isotropic with and effective correlation frequency 106 – 107 Hz. A globular structure of the associates of s-PMMA is proposed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00254590
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  • 7
    Electronic Resource
    Electronic Resource
    Polymerization of isobutylene initiated with the system 2,5-dichloro-2,5-dimethylhexane/SnCl4 (1992)
    Springer
    Polymer bulletin 28 (1992), S. 167-174 
    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 polymerizations of isobutylene in dichloromethane at-20°C initiated with the system 2,5-dichloro-2,5-dimethylhexane (DDH)/SnCl4 were investigated. The polyisobutylene (PIB) samples obtained were examined by GPC and their molecular weight distribution curves were determined. It was found that PIB products obtained by the conventional procedure have a bimodal MWD and the weight content of the lower-molecular weight fraction increases with increasing concentration of DDH in the polymerization feed. The effect of ageing of DDH/SnCl4 mixtures prepared in advance on MWD of the PIB samples was also proved. The results achieved lead to a conclusion that the ageing of the initiation system consists probably in the formation of the complex DDH-SnCl4-H2O, which protogenically again initiates the oligomerization of isobutylene, giving rise to oils with a narrow MWD, the polydispersity index $${{\bar M_{_w } } \mathord{\left/ {\vphantom {{\bar M_{_w } } {\bar M_n }}} \right. \kern-\nulldelimiterspace} {\bar M_n }} \leqslant 1.3$$ . The possible role of the coordination polymerization mechanism is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00299652
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  • 8
    Electronic Resource
    Electronic Resource
    Isobutylene polymerization in the presence of t-BuCl/SnCl4 (1992)
    Springer
    Polymer bulletin 28 (1992), S. 175-180 
    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 effect of tert-butyl chloride in the polymerizations of isobutylene carried out in the presence of SnCl4 in dichloromethane at temperatures-20°C and-78°C was investigated. Synthesized polyisobutylene samples showed a bimodal molecular weight distribution (MWD) and it was found that the weight content of the lowermolecular weight (LMW) fraction increased with increasing t-BuCl concentration in the polymerization mixture. The effect of ageing of the initiation mixture t-BuCl/SnCl4 in CH2Cl2 prepared in advance on MWD of the PIB samples was also studied. Ageing of the initiation system supports the formation of the LMW fraction and this oily PIB is the only product of the polymerization at-20°C, $$\bar M_n \sim 500,\bar M_w /\bar M_n \leqslant 1.4$$ .
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00299653
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  • 9
    Electronic Resource
    Electronic Resource
    13C NMR characterization of unsaturated terminal structures in oligoisobutylenes (1995)
    Springer
    Polymer bulletin 34 (1995), S. 461-467 
    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 13C NMR analysis revealed the existence of additional unsaturated terminal structures in oligoisobutylene samples, in addition to the well-known-CH2C(CH3)=CH2 and-CH=C(CH3)2. Structure with a double bond between two quaternary carbons was detected both in commercial Oppanol B3 and in a oligoisobutylene (PIB) sample prepared by polymerization in CH2Cl2 with a high concentration of monomer in the presence of BCl3 at-20°C. In the latter sample, another type of the structure with a double bond between quaternary carbon and methine carbon (-CH=C(CH3)-CH2CH3) was found in a large amount.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00306241
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  • 10
    Electronic Resource
    Electronic Resource
    Characterization of the structure of the stereocomplex of poly(methyl methacrylate) in solution from NMR relaxation data (1975)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 176 (1975), S. 729-743 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Mit dem Impulsspektrometer bestimmte Relaxationszeiten T2, sowie Linienformen in Hochauflösungs- und Breitband-Kernresonanzspektren (HR- und BL-NMR) haben gezeigt. daß im assoziierten Stereokomplex von isotaktischem (it-) und syndiotaktischem (st-) Poly(methylmethacrylat) (PMMA) zwei Protonentypen vorkommen, die sich durch + Beweglichkeit unterscheiden. Aus der Analyse der unter dem magischen Winkel aufgenommenen Kernresonanzspektren (MAR-NMR) wurde gezeigt, daß die Beweglichkeit von Estergruppen im Stereokomplex weitgehend behindert ist. Aus der Temperaturabhängigkeit der HR-NMR Spektren der gemischten Lösungen von it- und st-PMMA in Benzol können die assoziierten Stereokomplexsegmente als Vernetzungspunkte eines Gerüstes von nichtassoziierten Sequenzen charakterisiert werden.
    Notes: From the values of relaxation times T2 determined on a pulse spectrometer, and from the shape of bands in high resolution (HR-) and broad line (BL-) NMR spectra, two types of protons, different in mobility, were found to exist in the associated stereocomplex of isotactic (it-) and syndiotactic (st-) poly(methyl methacrylate) (PMMA). From the analysis of NMR spectra, measured at magic angle rotation (MAR-NMR), the mobility of the ester groups in the stereocomplex is shown to be greatly hindered. Temperature changes of HR-NMR spectra of mixed solutions of it- and st-PMMA in benzene indicate that the associated segments of the stereocomplex can be characterized as junctions of a network of nonassociated sequences.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1975.021760315
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