Search results for "Tetraoctylammonium bromide"
showing 4 items of 4 documents
Epicyanohydrin: Polymerization by Monomer Activation Gives Access to Nitrile-, Amino-, and Carboxyl-Functional Poly(ethylene glycol)
2015
Both homo- and copolymerization of the hitherto nonpolymerizable epoxide monomer epicyanohydrin (EPICH) with ethylene oxide (EO) have been studied, employing the monomer activation technique. Tetraoctylammonium bromide or tetrabutylammonium iodide was used as initiator combined with i-Bu3Al to activate the EPICH monomer. The EPICH content was varied from 4 to 16 mol %, yielding well-defined PEG-co-PEPICH copolymers with molecular weights Mn (SEC) ranging from 3700 to 8800 g mol–1. The nitrile groups of the resulting polyethers were further reduced or hydrolyzed to introduce amino, amide, or carboxyl groups at the polyether backbone, circumventing protecting group chemistry. Successful trans…
Nano-composite thermochromic thin films and their application in Energy-efficient glazing
2010
A hybrid atmospheric pressure and aerosol-assisted chemical vapour deposition strategy is presented as a facile route for the production of vanadium dioxide nano-composite thin films. The effect of the inclusion of gold nanoparticles and the use of a surfactant molecule, tetraoctylammonium bromide, is discussed. The films were fully characterised using a wide variety of techniques, including scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and UV/vis/NIR spectroscopy. It is shown that micro-structural changes brought about by careful control of film growth conditions, and/or the use of surfactant, lead to an enhancement of thermochromic properties. Gold nano…
Synthesis of linear polyglycerols with tailored degree of methylation by copolymerization and the effect on thermorheological behavior
2017
Abstract We introduce a two-step strategy for the synthesis of linear polyglycerols (linPG-OHx/OMey) with an adjustable degree of methylation ( y = D M 100 ). Ethoxy ethyl glycidyl ether (EEGE) and glycidyl methyl ether (GME) were copolymerized via the “activated monomer” polymerization technique, using tetraoctylammonium bromide (NOct4Br) as an initiator and triisobutylaluminum (i-Bu3Al) as a catalyst under mild conditions. Subsequent acidic cleavage of the acetal protective groups generates linear polyglycerols with different degree of methylation (DM) by varying the GME comonomer content between 10 and 91%. Size exclusion chromatography (SEC) evidenced good control over molecular weight …
A Challenging Comonomer Pair: Copolymerization of Ethylene Oxide and Glycidyl Methyl Ether to Thermoresponsive Polyethers
2014
Motivated by the oxygen-rich and fully amorphous structure of poly(glycidyl methyl ether) (PGME), a series of thermoresponsive poly(glycidyl methyl ether-co-ethylene oxide) copolymers P(GME-co-EO) with molecular weights in the range of 3000–20 000 g mol–1 were synthesized by the activated monomer polymerization technique. Tetraoctylammonium bromide (NOct4Br) was employed as an initiator in combination with triisobutylaluminum (i-Bu3Al) as a catalyst under mild conditions. Polyethers with varying GME content between 31 and 100 mol % were obtained. Triad sequence analysis using 13C NMR spectroscopy proved that no pronounced block structure was obtained. Differential scanning calorimetry (DSC)…