In the first of a two‐part series, a study has been made of the anionic polymerization of a five‐membered cyclocarbosiloxane, 2,2,5,5‐tetramethyl‐1‐oxa‐2,5‐disilacyclopentane. The polymerization was initiated by lithium n‐butyldiphenylsilanolate in the presence of tetrahydrofuran. The chemical shifts of the protons of the cyclic monomer and the polymer were found to be different, and therefore the rate of polymerization was obtained in an NMR spectrometer. The effects of varying the concentrations of THF, initiator, and water upon the rate of polymerization and upon the molecular weight and the molecular weight distribution were investigated. At a constant concentration of monomer and initiator, the rate of polymerization increased when the THF concentration was increased. At a constant concentration of monomer and THF the rate of polymerization reached a constant value when the initiator concentration was varied. The molecular weight and the molecular weight distribution were dependent upon the initiator to water ratio, whereas water concentration had little effect on the rate of polymerization. Essentially monodispersed polymers were obtained when the concentration of initiator was in large excess to that of water or vice versa. A bimodal distribution in molecular weight was obtained when the concentration of initiator was approximately equal to that of water. The apparent activation energy of polymerization was 12.7 kcal/mole.
A study was conducted of the anionic polymerization of a series of methyl‐ and/or phenyl‐substituted five‐membered cyclocarbosiloxanes. The polymerization was initiated by lithium n‐butyldiphenylsilanolate in the presence of tetrahydrofuran. The rate of conversion of monomer to polymer was measured in an NMR spectrometer. The rate of polymerization was largely dependent upon the structure of the growing chain ends. The apparent activation energies were in the range 10–14 kcal/mole for the series.
Ionic polyesters of fairly low molecular weights were prepared by melt phase polytransesterification of 1,l'-bis(carbethoxy)cobalticinium hexafluorophosphate (1 a) and diols such as 1,lO-decanediol and 1,4-bis(hydroxymethyl)benzene. Attempts to prepare polyamides by melt condensation from alkylene diammonium salts of 1,l'-bis(carboxy)cobalticinium hexafluorophosphate 5a-d resulted in extensive decomposition, and pure polyamides could not be obtained. The polyesters were characterized by analyses, IR spectroscopy, gel permeation chromatography, and differential scanning calorimetry.
ZUSAMMENFASSUNG:Ionische Polyester mit ziemlich niedrigen Molekulargewichten wurden dargestellt durch Polyumesterung von l,l'-Bis(carbathoxy)kobalticiniumhexafluorphosphat (la) und den Diolen 1,lO-Decandiol bzw. 1,4-Bis(hydroxymethyI)benzol in der Schmelze. Versuche Polyamide durch Schmelzkondensation aus Alkylendiammonium-Salzen des 1,1 '-Bis(carboxy)kobalticiniumhexafluorphosphats darzustellen, fiihrten zu weitgehender Zersetzung. Die Polyester wurden durch Analysen, IR-Spektroskopie, Gelchromatographie und Differentialkalorimetrie charakterisiert.
JntroductionWhile a large number of papers on ferrocene-containing polymers have appeared' q 2 , reports of metallocinium-containing polymers are rare. Pittman
Recent studies in our laboratory have required the use of N,N-dimethylformamide (DMF) as the solvent for gel-permeation chromatography (GPC). An intrinsic viscosity-molecular weight (h1-M) relation for polystyrene in DMF was needed in order to determine a GPC calibration curve based upon hydrodynamic volume (i.e., on the product [VIM). The intrinsic viscosity-molecular weight relationship for polystyrene in DMF reported here comprises the results of this work.
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