A new route to stereoregular poly(vinyl alcohols)

Murahashi, Shunsuke; Nozakura, Shun‐ichi; Sumi, Masao

doi:10.1002/pol.1965.110030402

Cited by 60 publications

(23 citation statements)

References 7 publications

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“…Isotactic PVAs were synthesized successfully from poly(vinyl ether)s such as poly(benzyl vinyl ether) (PBzVE), 4,5 poly(tert-butyl vinyl ether) (PtBVE), 6,7 and poly(trimethyl silyl vinyl ether) (PVOSi), 8,9 and their physical properties were also investigated.…”

Section: -3mentioning

confidence: 99%

“…A series of radical-polymerized poly(vinyl ester)s was utilized to synthesize syndiotactic PVAs, and the relationships between stereoregularity and physical properties of PVA have been examined. [1][2][3] Isotactic PVAs were synthesized successfully from poly(vinyl ether)s such as poly(benzyl vinyl ether) (PBzVE), 4,5 poly(tert-butyl vinyl ether) (PtBVE), 6,7 and poly(trimethyl silyl vinyl ether) (PVOSi), 8,9 and their physical properties were also investigated. 1,3 Despite the above efforts, the stereoregularity still remained at a low level of the mm fraction (¼ 0:70) even for so-called isotactic PVA (LI-PVA) derived from PVOSi.…”

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Highly Isotactic Poly(vinyl alcohol) Derived from tert-Butyl Vinyl Ether V. Viscoelastic Behavior of Highly Isotactic Poly(vinyl alcohol) Films

Ohgi

Sato

Watanabe

et al. 2006

Polym J

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ABSTRACT:Dynamic viscoeasticity of poly(vinyl alcohol) with high isotacticity (HI-PVA, mm ¼ 0:78), being derived from tert-butyl vinyl ether, was investigated to compare with that of syndiotactc PVA (S-PVA, mm ¼ 0:14) and commercial atactic PVA (A-PVA, mm ¼ 0:22). In the non-crystalline region, the a (local twisting motion) and a (micro-Brownian motion) dispersions occurring at around À10 C and 70 C were nearly the same, in both magnitude and location, for the HI-PVA and S-PVA having an almost identical degree of crystallinity. On the other hand, in the crystalline region, the c and c dispersions of HI-PVA were somewhat different from those of ordinary PVAs. The c dispersion (local motion in crystals due to defects) was clearly observed for HI-PVA but not for S-PVA and A-PVA. The c dispersion (axial motion of the chain in the crystal lattices) was observed for all PVA films but its temperature increased in the order of HI-PVA > S-PVA > A-PVA, which well corresponded to the order of the melting temperature and 13 C spin-lattice relaxation time (T 1C ) of each stereoregular PVA. These differences may be attributed to a difference of the magnitude of intermolecular and/or intramolecular hydrogen bonding in the crystals of respective PVAs. Specifically, the successive intramolecular bonding in the HI-PVA crystal appears to reduce the magnitude of the intermolecular bonding thereby allowing the chain to exhibit the c motion. This successive bonding would also stiffen the chain backbone thereby increasing the c dispersion temperature. [doi:10.1295/polymj.PJ2005235] KEY WORDS Highly Isotactic Poly(vinyl alcohol) / Stereoregular Polymerization / Viscoelasticity / Many efforts have been made for synthesis of stereoregular poly(vinyl alcohol)s (PVAs) being rich in syndiotactic or isotactic sequences 1-3 and changes of their physical properties with the stereoregularity, possibly reflecting changes in the inter-and intramolecular hydrogen bonding, have been extensively investigated. A series of radical-polymerized poly(vinyl ester)s was utilized to synthesize syndiotactic PVAs, and the relationships between stereoregularity and physical properties of PVA have been examined. 1-3Isotactic PVAs were synthesized successfully from poly(vinyl ether)s such as poly(benzyl vinyl ether) (PBzVE), 4,5 poly(tert-butyl vinyl ether) (PtBVE), 6,7 and poly(trimethyl silyl vinyl ether) (PVOSi), 8,9 and their physical properties were also investigated. 1,3Despite the above efforts, the stereoregularity still remained at a low level of the mm fraction (¼ 0:70) even for so-called isotactic PVA (LI-PVA) derived from PVOSi.9,10 Recently, we studied the cationic polymerization of tBVE with boron trifluoride diethyl etherate (BF 3 . OEt 2 ) and successfully prepared the PVAs having the highest isotacticity so far reported. [10][11][12] We found interesting features of these highly isotactic PVAs (HI-PVAs) being different from those of LI-PVA and ordinary atactic PVA (A-PVA). 10,13,14 In particular, we compared the melting temperature T m , degree...

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Section: -3mentioning

confidence: 99%

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confidence: 99%

Highly Isotactic Poly(vinyl alcohol) Derived from tert-Butyl Vinyl Ether V. Viscoelastic Behavior of Highly Isotactic Poly(vinyl alcohol) Films

Ohgi

Sato

Watanabe

et al. 2006

Polym J

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“…This may be accomplished by co-polymerizing isobutylene (66) and (trimethylsiloxy)ethylene (67) , removing the protecting silyl group, and acetylating to yield poly(vinyl acetate-co-isobutylene) (see Figure 26). …”

Section: Recommended Future Workmentioning

confidence: 99%

INEXPENSIVE CO{sub 2} THICKENING AGENTS FOR IMPROVED MOBILITY CONTROL OF CO{sub 2} FLOODS

Enick¹,

Beckman²,

Hamilton³

2004

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The objective of this research was the design, synthesis and evaluation of inexpensive, nonfluorous carbon dioxide thickening agents. We followed the same strategy employed in the design of fluorinated CO 2 polymeric thickeners. First, a highly CO 2 -philic, hydrocarbon-based monomer was to be identified. Polymers or oligomers of this monomer were then synthesized. The second step was to be completed only when a CO 2 -soluble polymer that was soluble in CO2 at pressures comparable to the MMP was identified. In the second step, viscosity-enhancing associating groups were to be incorporated into the polymer to make it a viable thickener that exhibited high CO 2 solubility at EOR MMP conditions. This final report documents the CO 2 solubility of a series of commercial and novel polymers composed of carbon, hydrogen, oxygen and, in some cases, nitrogen.In the first section of the report, we demonstrate that poly(vinyl acetate), PVAc, is the most CO 2 soluble, inexpensive, commodity polymer that has yet been identified. The pressure required to dissolve PVAc in CO 2 was 6000 -9000 psia; thousands of psi greater than the range of MMP values. Therefore PVAc was not soluble enough in CO 2 to serve as the "base polymer" from which CO 2 thickeners would be developed. The next objective of this investigation was to determine if any polymer (composed of C, H, O, N and/or S) could exhibit CO 2 solubility greater than that of PVAc.The second section is a report on the comparison of CO 2 -philicity of oxygenated hydrocarbon side groups on a PDMS polymer. These side-functionalized PDMS polymers are not candidates for a CO 2 thickener because they contain silicon, nonetheless the PDMS backbone provides a highly CO 2 -soluble molecular framework onto which the side chains composed of C, H, O and N can be grafted. The side groups that interacted most favorably with CO 2 caused the functionalized PDMS molecule to have the greatest miscibility with CO 2 . These results provided a useful tool for comparing the CO 2 -philicity of various side chains, and the most promising side groups were incorporated into a polymer containing neither silicon nor fluorine. Both ethers and acetates appeared particularly promising. To date, these polymers have not been more CO 2 -soluble than PVAc.The third section is a report on a novel class of highly CO 2 soluble compounds known as sugar acetates. Low molecular weight sugar acetates are remarkably CO 2 soluble. Although we were successful in designing CO 2 soluble hydrogen bonding compounds, they were not capable of thickening the CO2. High molecular weight sugar acetate polymers, cellulose triacetate and peracetlyated xanthan gum, were insoluble in CO2.The fourth section is a report on a novel type of phase behavior that was discovered while studying the sugar acetates. Highly CO 2 -philic solids, including small molecules and polymers, can exhibit melting point depression in dense CO 2 , i.e. these solids melt instantly in dense CO 2 . This phenomenon is symptomatic of a favorable thermody...

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“…The effects of polymer modifications by substitution with triorganosilyl groups (silylation) have been demonstrated 30 years ago; the increased solubility of silylated polymers in nonpolar solvents is particularly note worthy. [1][2][3] The silylcellulose derivatives have various uses; as fibers, 4 films, or liquid crystals, 5,6 a search in the literature revealed that rather a small number of studies are devoted to characterization of these compounds, especially in solution, a reduced number of studies are devoted to characterization of these compounds in solution. Most likely, this lack is perhaps determined both by synthesis difficulties and by the fact that in the absence of some peculiar measures of precaution, unstable products are obtained.…”

Section: Introductionmentioning

confidence: 99%

The rheological and structural behavior of silylcellulosics derivatives

Bontea¹

2001

J of Applied Polymer Sci

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ABSTRACT:The trimethylsilylcellulose (TMSC) samples were characterized in solution by osmometry, viscometry, and gel permeation chromatography. The Mark-HouwinkSakurada (M-H-S) equation coefficients were determined in chloroform, 1,1,1-trichloroethane, and o-xylene, in all cases the exponent "a" being higher than unit, this indicating a great stiffness of the macromolecules in solution. Also, the temperature dependence of the limiting viscosity number and M-H-S coefficients respectively for TMSC in o-xylene were studied. The exponent from M-H-S equation is also higher than unit, and increases linearly with the temperature. The GPC studies indicates a relative high polydispersity of the studied samples; the polydispersity index being situated between 2 and 3. The change of the crystalline structure as the result of silylation reaction was evidenced, the crystallinity of silyl derivatives depending on the substitution degree (DS), and the molecular weight. The viscous flow parameters for dilute solutions of trimethylsilylcellulose in o-xylene were determined in the temperature range 30 -70°C. The temperature dependence of the dynamic viscosity of the solutions obeys an Arrhenius-type equation in which the apparent activation energy is linearly dependent on both the solution's concentration and molecular weight. For preexponential factor no significant dependence on concentration and molecular weight was found. This behavior was attributed to the very great stiffness of the macromolecular chains.

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A new route to stereoregular poly(vinyl alcohols)

Cited by 60 publications

References 7 publications

Highly Isotactic Poly(vinyl alcohol) Derived from tert-Butyl Vinyl Ether V. Viscoelastic Behavior of Highly Isotactic Poly(vinyl alcohol) Films

Highly Isotactic Poly(vinyl alcohol) Derived from tert-Butyl Vinyl Ether V. Viscoelastic Behavior of Highly Isotactic Poly(vinyl alcohol) Films

INEXPENSIVE CO{sub 2} THICKENING AGENTS FOR IMPROVED MOBILITY CONTROL OF CO{sub 2} FLOODS

The rheological and structural behavior of silylcellulosics derivatives

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