The mechanistic aspects of the stereoregular polymerization of propylene oxide

Öktem, Zeki


Characterization and study of solution properties of poly(propylene oxide) synthesized by metal xanthate catalysts
Tarkın, Eylem; Alyürük, Kemal; Department of Polymer Science and Technology (2003)
Zinc xanthates polymerize propylene oxide into high polymer (PPO) with coordination mechanism. In order to identify structure and stereoisomerisms of this polymer, PPO was subjected to thermal and column fractionation. Obtained fractions were characterized by end-group analysis, cryoscopy, viscometry, IR and 13C-NMR spectroscopy, melting temperature. PPO is composed of a high molecular weight, stereoregular, crystallizable polymer (K-polymer) with low molecular weight (=500 g/mol) D-polymer. Presence of dou...
A density functional theory study of partial oxidation of propylene on Cu2O(001) and CuO(001) surfaces
Duzenli, Derya; Atmaca, Deniz Onay; Gezer, Miray Gulbiter; Önal, Işık (2015-11-15)
This work theoretically investigates propylene epoxidation reaction on Cu2O(001) and CuO(001) surfaces using periodical DFT method to determine the active copper species within the reaction mechanism. The transition states and energy profiles are calculated for the formation of surface intermediates such as oxametallopropylene (OMP) over Cu2O(0 0 1) and oxygen bridging (OB) over CuO(0 0 1) and allylic H-stripping reaction (AHS) over both surfaces as well as for formation of products. Propylene oxide (PO) an...
The performance of polyethersulfone nanocomposite membrane in the removal of industrial dyes
Mahmoudian, Mehdi; Ghasemıkouchameshgı, Mahmoud (2021-05-14)
In the present study, graphene oxide was functionalized by hyperbranched epoxy and then used as an additive in the polyethersulfone membrane. The process of preparation and characterization of the synthesized hyperbranched epoxy, and graphene oxide modification was investigated by some analysis such as XRD, EDAX, FTIR, NMR, and TGA. Morphology of modified nanostructures, their distribution in the membrane matrix, and morphology of membranes were evaluated by TEM, FESEM analysis. Experimental results showed ...
A Mechanism for the stereoregular polymerization of propylene oxide by the pruitt-baggett catalyst
Takrouri, Fahed; Alyürük, Kemal; Department of Chemistry (1991)
The glass transition behaviour and thermodynamic properties of amorphous polystyrene
Aras, Leyla; Richardson, Maxwell J. (Elsevier BV, 1989-12)
The effect of molecular weight (MW) and thermal history on the heat capacity (cp) of amorphous polystyrene over the temperature range from 200–440 K has been measured using differential scanning calorimetry (d.s.c.) General equations are given that show the influence of MW on cp in both the glassy and liquid states. An enthalpic definition of the glass temperature reflects changes in the glass structure, due to thermal history, that are not found using conventional d.s.c. constructions. Thermodynamic and st...
Citation Formats
Z. Öktem, “The mechanistic aspects of the stereoregular polymerization of propylene oxide,” Ph.D. - Doctoral Program, Middle East Technical University, 1991.