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Polymer Chemistry

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Articles 61 - 63 of 63

Full-Text Articles in Physical Chemistry

Synthesis Of Chemically Produced Toner (Cpt) By Emulsion Aggregation Process., Ng Wei Goon Apr 2010

Synthesis Of Chemically Produced Toner (Cpt) By Emulsion Aggregation Process., Ng Wei Goon

Student Works (2010-2019)

This project studied the full process of producing Chemically Produced Toner (CPT) used in laser printer. Latex particles of 0.40 to 0.60 μm were prepared by semicontinuous emulsion polymerization process. A series of latexes was made from the copolymerization of styrene, butyl acrylate and acrylic acid monomers in the presence of surfactants Dowfax 2A1 (anionic) and Ipegal 897 (non-ionic) surfactants with potassium persulphate as the initiator. The addition of different percentage of chain transfer agent (CTA), 1-dodecanethiol was used to control the molecular weight distribution. As the percentage of CTA was increased, the molecular weight and glass transition temperature decreased …


A Novel Tio2 / Pvc Layer For Use In A Photoelectrochemical Cell, Faiza Touati, John Cassidy, Kevin Mcguigan Jan 2007

A Novel Tio2 / Pvc Layer For Use In A Photoelectrochemical Cell, Faiza Touati, John Cassidy, Kevin Mcguigan

Articles

A novel method of coating titanium dioxide on a glassy carbon electrode as a polyvinylchloride composite , is described. On illumination , there is an enhanced voltammetric current at this TiO2/PVC composite in aqueous formic acid solution. This electrode is used as the basis of a formic acid fuel cell where oxygen is reduced at a platinum cathode. The system yields 100 cm-2 for 0.01 mol dm-3 HCOOH in 0.1 mol dm-3 NaOH under illumination from a 150 W xenon lamp. The current without illumination is 0.5 cm-2.


Gas Permeation Measurements On Small Polymer Specimens, Karen S. Burns Oct 1987

Gas Permeation Measurements On Small Polymer Specimens, Karen S. Burns

Chemistry & Biochemistry Theses & Dissertations

Mass spectrometry was used to measure oxygen and nitrogen permeabilities while polarography was used to measure oxygen permeabilities for several contact lens materials. Applicable sample holders were designed and fabricated to accommodate curved and flat specimens with surface areas of 0.5 cm2 and 1.0 cm2 and thicknesses between 0.025 mm and 0.500 mm. A prepared standard was used to calibrate the mass spectrometric analyses.

The oxygen permeability values determined by mass spectrometry were significantly greater than those determined by polarography. This was attributed to the phase boundary phenomena and the limiting oxygen permeance of water inherent in the …