<sup>13</sup>C NMR Studies on Some Poly(alkene sulfone)s

Fawcett, Allan H.; Heatley, Frank; Ivin, K. J.; Stewart, C. D.; Watt, P.

doi:10.1021/ma60058a009

Cited by 41 publications

(14 citation statements)

References 8 publications

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“…Carbons a and b are responsible for the resonances at 13 and 22 ppm, respectively, but carbons c and d appear together as a broad resonance centred at 28 ppm, a feature not observed in the polysulfides. The reason for this is that carbon d experiences a γ oxygen effect (γ O2 ) from the sulfone oxygens1 (Callan JF and Fawcett AH, unpublished), which moves it upfield by 6 ppm to the vicinity of carbon c , which cannot experience this effect. Again, backbone carbons e and f appear furthest downfield at 49 and 57 ppm, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…Poly(olefin sulfone)s (POSs) prepared by the free radical copolymerisation of an olefin and sulfur dioxide are atactic according to 13 C NMR 1–4. The polymers made from the 1‐olefins have been shown to form helical conformations in solution and on a surface and to display main‐chain liquid‐crystalline behaviour in the bulk, only when they possess long side‐chains 2, 5, 6.…”

Section: Introductionmentioning

confidence: 99%

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Isotactic poly(1‐hexene sulfone)s by stereoselective anionic ring‐opening polymerisation

Callan

Fawcett

2007

Polymer International

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BACKGROUND: Poly(olefin sulfone)s have been shown to form helical regions and to display main-chain liquidcrystalline behaviour in the bulk when they possess long side-chains. It is believed that increasing the tacticity of the backbone could enhance their liquid-crystalline behaviour. This study aims to produce tactic poly(olefin sulfone)s by stereospecific ring-opening polymerisation.RESULTS: Tactic polythiranes were successfully obtained from a racemic mixture of thirane monomers using a series of chiral catalyst systems. The isotactic placement (P i ) was determined using 13 C NMR analysis of carbons in or near the backbone. The polysulfides were oxidised by peracetic acid to their corresponding polysulfones. Powder X-ray diffraction studies showed that the isotactic polysulfones formed more ordered structures than their atactic analogues, an effect attributed to a tightening of the helical pitch. CONCLUSIONS: Tactic poly(1-hexene sulfone)s have been prepared for the first time by stereoselective ringopening polymerisation.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Isotactic poly(1‐hexene sulfone)s by stereoselective anionic ring‐opening polymerisation

Callan

Fawcett

2007

Polymer International

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“…It is therefore not easy to distinguish between models for motion based on a single exponential or a sum of exponential correlation functions in time. However, this is not of great importance in distinguishing between the rates of motion for individual groups and is of no importance in distinguishing between segmental and overall motionsas was achieved for the polyolefin sulphones .21 5*221 a* 222 We note that in addition to the 13C n.m.r. and fluorescence-depolarization techniques for following the motions of specific groups in polymer chains, such motions may also be studied through the motions of nitroxide spin-labels covalently attached to the chains.…”

Section: Light Scatteringmentioning

confidence: 84%

Chapter 5. Studies of molecular motion in liquids and solids using low frequency dielectric relaxation and related techniques

Williams¹,

Crossley²

1977

Annu. Rep. Prog. Chem., Sect. A. Inorg. and Phys. Chem

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IntroductionThe translational and reorientational motions of whole molecules or parts of molecules may be studied by spectroscopic, relaxation, and scattering techniques which cover in total the frequency range 10-4-1013 Hz. Dependent upon molecular structure and the phase (liquid, supercooled liquid, glass, crystal, or liquid crystal) and temperature and applied pressure, molecular motions may be observed anywhere in this large frequency range. For the purposes of the present account the range may be arbitrarily divided into three parts: (i) lo1' H z < v < 1013 Hz; (ii) 10' Hz< Y < lo1' Hz; (iii) Hz< Y < 10' Hz. For range (i) the fast motions of molecules are observed e.g. for small molecules in the liquid state or rotator-phase crystalline state. Such motions may be studied using near i.r. and Raman vibrationrotation spectroscopy,'*2 far i.r. ~pectroscopy,~ inelastic light-scattering spectros-copy4 (polarized and depolarized Rayleigh line-broadening) and neutron scattering ~pectroscopy,~ microwave dielectric relaxation techniques,6 and pico-second Kerreffect relaxation technique^.^ A recent text which gives the results of extensive studies of mainly non-viscous liquids is that by Lascombe.' The theoretical approach to molecular motion involves time-correlation functions, and advanced4.'-l2 and more elementary review^'^-'^ of these quantities are available

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“…Poly(olefin sulfone)s (POS's), the alternating copolymers of an olefin and sulfur dioxide prepared directly from these two monomers by a free-radical mechanism, are atactic according to 13 C-NMR spectroscopy. − We wish to prepare tactic POS's for two reasons. First, atactic poly(eicosene sulfone) and poly(hexadecene sulfone) are known to adopt helical conformations in nonpolar solvents, , as well as when isolated upon a surface, and to exhibit main chain liquid crystalline behavior in the bulk .…”

Section: Introductionmentioning

confidence: 99%

(−)-Poly((R)-1-octen-3-ol sulfone): The ¹³C-NMR Fine Structure of the First Partially Isotactic Poly(olefin sulfone) Prepared by a Free-Radical Mechanism

Fawcett¹,

Malcolm²

1997

Macromolecules

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Poly(olefin sulfone)s have been prepared from (R)- and (RS)-1-octen-3-ol, in which the chiral centers are adjacent to the double bond. The 13C-NMR spectra of the polymers have shown that the stereochemistry of the main chain methine carbon formed in the propagation reaction depended primarily upon that of the side chain chiral carbon within the same residue. The polysulfone of (R)-(−)-1-octen-3-ol is therefore the first partially isotactic polysulfone to be prepared by a free-radical polymerization. Large dispersions of chemical shift and well-resolved fine structure in the 13C-NMR spectra have allowed assignments to be made of sequence and intraresidue effects in isotactic and atactic polymers at the main chain tetrad level.

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¹³C NMR Studies on Some Poly(alkene sulfone)s

Cited by 41 publications

References 8 publications

Isotactic poly(1‐hexene sulfone)s by stereoselective anionic ring‐opening polymerisation

Isotactic poly(1‐hexene sulfone)s by stereoselective anionic ring‐opening polymerisation

Chapter 5. Studies of molecular motion in liquids and solids using low frequency dielectric relaxation and related techniques

(−)-Poly((R)-1-octen-3-ol sulfone): The ¹³C-NMR Fine Structure of the First Partially Isotactic Poly(olefin sulfone) Prepared by a Free-Radical Mechanism

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13C NMR Studies on Some Poly(alkene sulfone)s

Cited by 41 publications

References 8 publications

Isotactic poly(1‐hexene sulfone)s by stereoselective anionic ring‐opening polymerisation

Isotactic poly(1‐hexene sulfone)s by stereoselective anionic ring‐opening polymerisation

Chapter 5. Studies of molecular motion in liquids and solids using low frequency dielectric relaxation and related techniques

(−)-Poly((R)-1-octen-3-ol sulfone): The 13C-NMR Fine Structure of the First Partially Isotactic Poly(olefin sulfone) Prepared by a Free-Radical Mechanism

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Resources

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¹³C NMR Studies on Some Poly(alkene sulfone)s

(−)-Poly((R)-1-octen-3-ol sulfone): The ¹³C-NMR Fine Structure of the First Partially Isotactic Poly(olefin sulfone) Prepared by a Free-Radical Mechanism