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  • 1
    Electronic Resource
    Electronic Resource
    Ring opening during the cationic polymerization of 2-methylene-1,3-dioxepane: Cyclic ketene acetal initiation with sulfuric acid supported on carbonSee Reference 1. (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 485-491 
    Details
    ISSN: 0887-624X
    Keywords: 2-methylene-1,3-dioxepane ; cyclic ketene acetal ; cationic polymerization ; activated carbon black ; 1,2-polymerization ; ring-opening polymerization ; ring-retained polymerization ; initiator ; catalyst ; heterogeneous catalysis ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The stable cyclic ketene acetal, 2-methylene-1,3-dioxepane, 7, has been polymerized cationically in pentane, CH2Cl2 and THF at 25°C to form a polymer which is composed of both ring-opened (40-50%) and ring-retained (50-60%) structures. Initiation was catalyzed by using H2SO4-supported on activated carbon black. This unique outcome differs significantly from the cationic polymerization of several other five- and six-membered ring cyclic ketene acetals which gave 100% 1,2-vinylpolymerization under these conditions. As the polymerization temperature increased in cationic polymerization of 7 the ring-opened content increased and the molecular weight of the polymers decreased in such solvents as cyclohexane, 1,2-dichloroethane, dimethoxyethane, and bis-(2-methoxyethyl) ether. The mechanism of this polymerization is discussed. This research also illustrated the ability to initiate the cationic polymerization of cyclic ketene acetals by acidified carbon black while avoiding subsequent polymer decomposition. © 1997 John Wiley & Sons, Inc.
    Additional Material: 1 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    Cationic copolymerization of 2-methylene-5,5-dimethyl-1,3-dioxane with 2-methylene-1,3-dioxolane and 2-methylene-1,3-dioxane (1996)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 34 (1996), S. 2195-2203 
    Details
    ISSN: 0887-624X
    Keywords: cationic polymerization ; copolymerization ; cyclic ketene acetal ; reactivity ratio ; 2-methylene-3-dioxolane ; 2-methylene-5,5-dimethyl-3-dioxane ; 2-methylene-3-dioxane ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Copolymers of the cyclic ketene acetals, 2-methylene-5,5-dimethyl-1,3-dioxane, 3, (M1) with 2-methylene-1,3-dioxolane, 4, (M2) or 2-methylene-1,3-dioxane, 5, (M2), were synthesized by cationic copolymerization. An experimental method was designed to study the reactivity of these very reactive and extremely acid sensitive cyclic ketene acetal monomers. The reactivity ratios, calculated using a computer program based on a nonlinear minimization algorithm, were r1 = 6.36 and r2 = 1.25 for the copolymerization of 3 with 4, and r1 = 1.56 and r2 = 1.42 for the copolymerization of 3 with 5. FTIR and 1H-NMR spectra when combined with the values of r1 and r2 showed that these copolymers were formed by a cationic 1,2-polymerization (ring-retained) route. Furthermore the tendency existed to form very short blocks of M1 or M2 within the copolymers. Cationic copolymerization of cyclic ketene acetals have the potential to be used for synthesis of novel polymers. © 1996 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    Stable polymers from cyclic ketene acetals: Cationic polymerization initiated by acid-washed glassware or acid-washed glass beadsTaken, in part, from Ref. 1. (1996)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 34 (1996), S. 169-174 
    Details
    ISSN: 0887-624X
    Keywords: cationic polymerization ; 1,2-polymerization of cyclic ketene acetals ; cyclic ketene acetal ; initiator ; catalyst ; acid-washed glass beads ; glassware ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Stable polymers were made by the cationic 1,2-polymerization of cyclic ketene acetals initiated by acid-washed glassware or acid-washed glass beads. Among several reactions possible for the very reactive cyclic ketene acetals, only the corresponding acetals of polyketene were formed. These structures were demonstrated by FTIR, 1H-NMR, and 13C-NMR analyses. © 1996 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    BF3·OEt2-initiated polymerization of 2-methylene-1,3-dioxepanes (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 873-881 
    Details
    ISSN: 0887-624X
    Keywords: 2-methylene-1,3-dioxepane ; 4,7-dimethyl-2-methylene-1,3-dioxepane ; cyclic ketene acetal ; cationic polymerization ; ring-opening polymerization ; ring-retained polymerization ; copolymerization ; boron trifluoride etherate ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: BF3·OEt2-initiated polymerizations of 2-methylene-1,3-dioxepane gave polymers composed of both ring-retained and ring-opened structures. The ring-opening content increased with an increase in polymerization temperature. Poly(4,7-dimethyl-2-methylene-1,3-dioxepane) propagated slower during BF3·OEt2-initiated polymerization and had a lower ring-opened content than poly(2-methylene-1,3-dioxepane). The type of acid initiator used also affected the amount of ring opening observed. Stronger acids gave less ring opening. Attempted BF3·OEt2-initiated copolymerizations of these seven-membered ring cyclic ketene acetals with isobutyl vinyl ether at room temperature resulted in formation of the two homopolymers. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 873-881, 1998
    Additional Material: 3 Ill.
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