Performance of a new cationic bleach activator on a hydrogen peroxide bleaching system

The performance of a cationic bleach activator, N -[4-(triethylammoniomethyl)benzoyl]caprolactam chloride, was evaluated in a hot peroxide bleaching process. The effect of time, temperature and the concentrations of hydrogen peroxide and activator on the bleaching of cotton fabric was investigated using a central composite experimental design. Temperature was found to be the most significant parameter. By adding the cationic activator it was possible to achieve a level of whiteness comparable to a typical commercial bleaching system but under relatively mild conditions of time and temperature. As a consequence, chemical damage to the fabric could be reduced. The effect of the cationic bleach activator was compared to that of an anionic activator, nonanoyloxybenzene sulphonate. The cationic activator was superior to the anionic activator in bleaching the fabric under the optimised conditions used in the study. Received: 13 January 2004, Accepted: 10 March 2004     

Polyimides from a Novel Monomer 3,6-Bis(dimethylamino)acridine(p-cymene)dichlororuthenium(II) for a Catalytic Application

Tricyclic heteroaraomatic dye-based monomer containing NMe₂ units, 6-bis(dimethylamino)acridine(p-cymene)dichlororuthenium (II), was used to prepare novel polyimides via a one-stage solution polycondensation due to their stability under a variety of oxidative and reductive conditions. The Ru(II) complex monomer was synthesized starting from [RuCl₂(p-cymene)]₂ and 3,6-bis(dimethylamino)acridine. A series of stable polyimides was synthesized from the Ru(II) complex of 3,6-bis(dimethylamino)acridine and various aromatic dianhyrides. The polymers had inherent viscosities ranging from 1.72 to 2.11 dL/g and were soluble in polar solvents. The glass transition temperatures were 192–278 °C, and the 10% weight loss temperatures were above 503–635 °C. Ruthenium-substituted polyimides were tested for catalytic activity in the furan formation reaction of (Z)-3-methylpent-2-en-4-yn-1-ol. The polymeric catalyst was added to (Z)-3-methylpent-2-en-4-yn-l-ol without a solvent and the pure furan was isolated by distillation under reduced pressure. The conversion of the starting, enynol, was determined by gas chromatography (GC).     

Polyimides from a Novel Monomer 3,6-Bis(dimethylamino)acridine(p-cymene)dichlororuthenium(II) for a Catalytic Application

Tricyclic heteroaraomatic dye-based monomer containing NMe₂ units, 6-bis(dimethylamino)acridine(p-cymene)dichlororuthenium (II), was used to prepare novel polyimides via a one-stage solution polycondensation due to their stability under a variety of oxidative and reductive conditions. The Ru(II) complex monomer was synthesized starting from [RuCl₂(p-cymene)]₂ and 3,6-bis(dimethylamino)acridine. A series of stable polyimides was synthesized from the Ru(II) complex of 3,6-bis(dimethylamino)acridine and various aromatic dianhyrides. The polymers had inherent viscosities ranging from 1.72 to 2.11 dL/g and were soluble in polar solvents. The glass transition temperatures were 192–278 °C, and the 10% weight loss temperatures were above 503–635 °C. Ruthenium-substituted polyimides were tested for catalytic activity in the furan formation reaction of (Z)-3-methylpent-2-en-4-yn-1-ol. The polymeric catalyst was added to (Z)-3-methylpent-2-en-4-yn-l-ol without a solvent and the pure furan was isolated by distillation under reduced pressure. The conversion of the starting, enynol, was determined by gas chromatography (GC).     

Conductive polyaniline/polyacrylonitrile composite fibers: Effect of synthesis parameters on polyaniline content and electrical surface resistivity

Conductive polyaniline/polyacrylonitrile (PAn/PAN) composite fibers were prepared by keeping PAN fibers in various solutions containing aniline and then by polymerization of aniline sorbed by fibers with potassium dichromate as an oxidant. In examined polymerization media, aqueous HCl gave composite fibers with the highest PAn amount and these fibers also had the lowest electrical surface resistivity. It was found that, as PAn content of PAn/PAN composite fibers increased, its density also increased and mechanical properties such as tensile strength and breaking elongation decreased. From optical cross‐section images of composite fibers, it was observed that PAn coating was limited only with the PAN fiber surface. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Exact numerical solutions for radiative heat transfer in cylindrical furnaces

Exact expressions for the distributions of the components of radiative flux density and the radiative energy source term in terms of wall and medium temperature distributions have been formulated for an emitting absorbing medium of constant properties bounded by black walls of a cylindrical enclosure. The accuracy of numerical solutions has been tested on an idealized enclosure for which exact analytical solution of the expressions is possible and shown to have six-figure accuracy. The exact expressions have then been solved numerically for an enclosure problem based on data reported previously on a large scale experimental furnace. The principal feature of the data is highly non-uniform temperature distributions which are typical of the conditions encountered in industrial furnaces. These data have been chosen because of their practical importance and the non-availability of exact solutions for such data. The resulting exact solutions have been tabulated and are intended to serve in the future as standards for testing the accuracy of the approximate predictions produced using various three-dimensional flux models in cylindrical configurations.     

Adhesion of aluminum films on polyimide by the electromagnetic tensile test

The electromagnetic tensile test has been adapted to the measurement of the adhesion of thin aluminum alloy films on polyimide. The adhesion per unit area was found to be weakly dependent on linewidth for lines as small as 5 μm. Processing conditions affected the adhesion with plasma ash and annealing steps improving the adhesion. Al 4% Cu was somewhat more adherent than Al-0.5% Cu.     

Fully differential stray-insensitive bilinear-z switched-capacitor highpass filter

A fully differential charge-domain bilinear-z SC highpass filter is proposed. This technique not only solves the stray-sensitive problem mentioned by Lee et al. but also provides some other advantages which are inherent in the differential structure.