Mechanism of Polymerization of 1, 3-Dioxolane Initiated by (C2H5)3 O+SbCl6 and SbCl5

The kinetics of polymerization of 1, 3-dioxolane (DiOX) initiated by (C₂H₅)₃O⁺SbCl₆ and SbCl₅ has been studied and the elementary stages of the process have been considered. The polymerization of DiOX by (C₂H₅)₃O⁺SbCl₆-is shown to proceed at a steady rate to high conversion. A constant concentration of active centers in the system is maintained due to the equal rates of decomposition of active centers and disproportionation. The nonsteady-state character of DiOX polymerization initiated by SbCl₅is associated with a relatively lower stability of the counter-ion SbCl₅ OR^? compared with SbCl₆. The initiation of DiOX polymerization by (C₂H₅)₃O⁺SbCl₆ proceeds without hydride-transfer reactions, and the concentration of active centers in the system is determined not by processes taking place in the initiation stage, but by the existence of a definite kind of equilibrium with the participation of active centers.     

Terpolymerization of propylene oxide,carbon dioxide,and trimethylene carbonate

High-molecular-weight polymers with different contents of propylene carbonate (PC), and trimethylene carbonate (TMC) units in the polymer chain were synthesized by the coordination anionic copolymerization of carbon dioxide, propylene oxide (PO), and TMC in supercritical carbon dioxide (scCO₂). Zinc adipate (ZnAd) was used as a catalyst. The terpolymerization products were characterized by ¹H and ¹³C NMR, IR spectroscopy, GPC, and DSC. The effect of the reaction conditions on the yield, composition, structure, and molecular weight and thermal characteristics of the terpolymers was studied. The phase behavior of the synthesized polymers and mixtures of polypropylene carbonate with polytrimethylene carbonate was examined.

     

Kinetic isotope effect 13C of cationic polymerization of oxygen-containing heterocycles. Structure of active centres. Mechanism of chain propagation

The results of studying the kinetic isotope effect of cationic polymerization of some oxygen-containing heterocycles are summarized. The use of this method made it possible to establish the oxonium mechanism of chain propagation and the existence of the step of preliminary monomer coordination on an active centre, preceding the polymeric chain propagation step.     

Anionic coordination copolymerization of propylene oxide,carbon dioxide,and l-lactide

Russian Chemical Bulletin - Terpolymers with various l-lactic acid content in the polypropylene carbonate chain were synthesized by copolymerization of carbon dioxide, propylene oxide, and...     

Mechanismus der Polymerisation von 1,3-Dioxolan mit (C2H5)3O-, SbCl6 und SbCl5

Ohne Zusammenfassung     

Copolymerization of propylene oxide with carbon dioxide catalyzed by zinc adipate

Copolymerization of carbon dioxide with propylene oxide in the presence of zinc adipate was studied. The effects of the temperature, nature of the solvent, and catalyst concentration on the molecular weight, molecular-weight distribution, and yields of the copolymer and propylene carbonate were examined. The structure of the polymer obtained was studied by ¹³N and ¹I NMR spectroscopy.     

Synthesis,structures, and thermal properties of terpolymers of propylene oxide,carbon dioxide,and cyclohexene oxide

High molecular weight block terpolymers with different contents of polypropylene carbonate and cyclohexene carbonate units in the polymer chain were synthesized by the copolymerization of carbon dioxide, propylene oxide, and cyclohexene oxide. Zinc adipate was used as a catalyst. The terpolymerization products were characterized by ¹H and ¹³C NMR spectroscopy, IR spectroscopy, GPC, DSC, and DMA methods. The influence of the reaction conditions on the composition, microstructure, and molecular-weight and thermal characteristics was studied.