POLYMETHYLALUMINIUM OXIDE AND STEREOREGULAR POLYMERIZATION OF PROPYLENE-OXIDE

Date

1993-05-01

Author

OKTEM, Z
SARI, A
ALYURUK, K

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

125
views

0
downloads

Polymethylaluminium oxide (PMAO) was prepared by reacting trimethylaluminium (AlMe3) with water in dilute dioxane solution. Several PMAO samples with different degrees of polymerizations (DP) were prepared (1 less-than-or-equal-to DP less-than-or-equal-to 7) either by changing reaction conditions or by fractionating the products. PMAO with DP about unity was found to be trimeric in dilute dioxane solutions but, in higher dielectric solvents, it partially dissociated into free ions. Electrical conductance measurements showed that the initially present ion-pairs were converted into another type of ion-pairs (solvent-bound ion-pairs) with a lower dissociation constant as the solution was aged. Catalytic activities of several PMAO samples in the stereoregular polymerization of propylene oxide were studied. Only a slight improvement of the stereoregular yield was observed by increasing the DP of the used catalyst. It was concluded that the methylaluminium oxide repeating units are the active species in the stereoregular polymerization and catalytic activity cannot be ascribed either to the presence of an ''undetected impurity'' or an ''unidentified unique structure of PMAO''.

Subject Keywords

Organic Chemistry, General Physics and Astronomy, Polymers and Plastics

URI

https://hdl.handle.net/11511/66798

Journal

EUROPEAN POLYMER JOURNAL

DOI

https://doi.org/10.1016/0014-3057(93)90121-u

Collections

Department of Chemistry, Article

Suggestions

OpenMETU
Core

ELECTRO-INITIATED POLYMERIZATION OF BIS-(2,4,6-TRIBROMOPHENOXO) ETHYLENEDIAMINE COPPER(II) COMPLEX IN DMF AND ITS KINETIC-STUDY BY CYCLIC VOLTAMMETRY Toppare, Levent Kamil; YIGIT, S; KISAKUREK, D; Akbulut, Ural (Elsevier BV, 1990-01-01) The decomposition of bis-(2,4,6-tribromophenoxo) ethylenediamine copper(II) complex in dimethylformamide by electro-oxidation yields low molecular weight (4.5 × 103) linear poly(dibromophenylene oxide). Electro-initiated polymerization was accomplished upon oxidation by a constant potential electrolysis under air or under N2 at room temperature. Polymerization conditions were based on the peak potentials measured by cyclic voltammetry. Constant peak potentials carried out at anodic and cathodic peak potenti...
GLASS-TRANSITION, CRYSTALLIZATION AND THERMOREVERSIBLE GELATION IN TERNARY PPO SOLUTIONS - RELATIONSHIP TO ASYMMETRIC MEMBRANE FORMATION BURGHARDT, WR; Yılmaz, Levent; MCHUGH, AJ (Elsevier BV, 1987-11-01) The phase equilibrium behaviour of PPO (poly 2,6-dimethyl-1,4-phenylene oxide) in mixtures of trichloroethylene with non-solvents ethanol, methanol or octanol has been studied. Attention has been given to the phenomena of glass transition, crystallization and thermoreversible gelation. The effect of solvent-non-solvent mixtures on the glass transition temperature depression was studied using differential scanning calorimetry (d.s.c.) and found to be well described by a ternary form of the Kelley-Bueche equa...
Electrochemical synthesis of crowned conducting polymers : nature of radical cations in polymerization and mechanism of conductivity Cihaner, Atilla; Önal, Ahmet Muhtar; Department of Chemistry (2004) Poly(dibenzo-18-crown-6) (Poly(DB18C6)) was synthesized by electrochemical oxidation of dibenzo-18-crown-6 (DB18C6) using a mixture of acetonitrile and dichloromethane as solvent and tetrabutylammonium tetrafluoroborate (TBABF4) or tetrabutylammonium hexafluorophosphate (TBAPF6) as supporting electrolyte. The anodic polymerization of DB18C6 was investigated using in-situ ESR and in-situ UV-VIS spectroscopic techniques. Spectroelectrochemical (SPEL) properties and thermal analysis of the resulting polymers h...
Cettaertalyst-Free Hydrogenation of Alkenes and Alkynes with Hydrazine in the Presence of Oxygen Menges, Nurettin; Balcı, Metin (Georg Thieme Verlag KG, 2014-03-17) A series of alkenes and alkynes was subjected to reduction with hydrazine hydrate in ethanol in the presence of oxygen. An efficient method was developed for the reduction of C-C double bonds and C-C triple bonds with diimide, generated in situ from hydrazine hydrate by oxidation with oxygen. The reduction process proceeded for 24-48 hours with high chemoselectivity and excellent yields. This reduction procedure offers synthetic advantages over metal-catalyzed hydrogenation as well as other systems.
MONOMER REACTIVITY RATIOS OF STYRENE-4-VINYLPYRIDINE COPOLYMERS AT LOW AND HIGH CONVERSIONS YILMAZ, E; KUCUKYAVUZ, Z (Elsevier BV, 1993-01-01) Monomer reactivity ratios in free-radical copolymerization of styrene and 4-vinylpyridine monomers at 80-degrees-C in toluene solution under reduced pressure were determined for low and high conversions. Finemann-Ross, Kelen-Tudos, extended Kelen-Tudos and Mayo-Lewis methods were used for this purpose. The most reliable method was found to be the extended Kelen-Tudos method. By the use of this method, for conversions below 20%, monomer reactivity values of 0.700 +/- 0.005 and 0.335 +/- 0.001 were calculated...

Citation Formats

Z. OKTEM, A. SARI, and K. ALYURUK, “POLYMETHYLALUMINIUM OXIDE AND STEREOREGULAR POLYMERIZATION OF PROPYLENE-OXIDE,” EUROPEAN POLYMER JOURNAL, pp. 637–643, 1993, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/66798.