Anionische Polymerisationen von 1, 3‐Cyclohexadien

Abstract

The molecular weights obtained in the anionic polymerization of 1.3‐cyclohexadiene are exclusively determined by chain transfer with monomer. No dissociation of the ion pairs on the active chain ends seems to occur. Arrhenius plots of the intrinsic viscosities against polymerization temperature yield straight lines going through a common isocinetic point. The activation energy differences of propagation and transfer could be estimated. The extent of chain transfer depends on the solvent and counter‐ion present. The disproportionation of cyclohexadiene to benzene and cyclohexene, sometimes observed instead of the polymerization, is shown to occur if the transfer constant approaches the magnitude of unity.

Early administration of abciximab bolus in the emergency department improves angiographic outcome after primary PCI as assessed by TIMI frame count: Results of the early ReoPro administration in myocardial infarction (ERAMI) trial

“…However, in contrast to conventional dienes (e.g., butadiene, isoprene), the polymerization of 1,3‐cyclohexadiene (1,3‐CHD) has sometimes been reported to be difficult under various conditions, including ionic polymerization, radical polymerization, and coordination polymerization. The polymers obtained under these conditions were of low molecular weight or in low yield, and the molar ratio of 1,2‐addition (the 1,2‐CHD unit) and 1,4‐addition (the 1,4‐CHD unit) of the polymer chain could not be controlled 1–5, 31–36…”

Thermal Degradation of Poly(1,3‐cyclohexadiene) and its Dehydrogenated Derivatives: Influence of a Controlled Microstructure

“…The polymers obtained under these conditions were of low molecular weight or in low yield, and the molar ratio of 1,2-addition (1,2-CHD unit) and 1,4-addition (1, to the polymer chain could not be controlled. [1][2][3][4][5][6][7][8][9][10][11][20][21][22][23][24][25] Before our discovery of the living anionic polymerization of 1,3-CHD, [26][27][28] there had been no successful examples for a method of controlled polymerization of 1,3-CHD, and it has been very difficult to elucidate the relationship between the microstructure and properties of PCHDs and their modified derivatives. In previous papers, [26][27][28][29] we reported the first successful example of living anionic polymerization of 1,3-CHD; homopolymers, copolymers, and block copolymers with narrow molecular weight distribution, controlled molecular weight and a clear polymer chain structure were successfully synthesized.…”

Kinetics and mechanism of the anionic polymerization of cyclohexadienes initiated by naphthalene radical anions and dianions

“…Note that the addition of a monomer to the hydronaphthyl Solid lines represent the experimental rates; dotted lines represent rates calculated by the computer iteration procedure from eq. (12). ilarly to the -SA-"dormant" ends2lvZ5 which do propagate the polymerization slowly through the reactions -SA-…”