Poly(trimethylene terephthalate) nanocomposite fibers comprising different organoclays: Thermomechanical properties and morphology

Poly(trimethylene terephthalate) (PTT) nano composites were synthesized by in situ polymerization at high temperature with two thermally stable organoclays: 1,2‐dimethylhexadecylimidazolium‐montmorillonite (IMD‐MMT) and dodecyltriphenyl phosphonium‐MMT (C₁₂PPh‐MMT). PTT hybrid fibers with various organoclay contents were melt‐spun at various draw ratios (DRs) to produce monofilaments. The thermomechanical properties and morphologies of the PTT hybrid fibers were characterized using differential scanning calorimetry, thermogravimetric analysis, wide‐angle X‐ray diffraction, electron microscopy, and mechanical tensile properties analysis. The nanostructure of the hybrid fibers was observed by both scanning and transmission electron microscopy, which showed that the clay layers were well dispersed into the matrix polymer, although some clusters or agglomerated particles were also detected. Unlike the hybrids containing IMD‐MMT, the clay layers of the C₁₂PPh‐MMT hybrid fiber were more dispersed into the matrix polymer. The thermal stability and tensile properties of the hybrid fibers increased with increasing clay content for DR = 1. However, as DR increased from 1 to 9 the ultimate strength and initial modulus of the hybrid fibers with IMD‐MMT increased slightly whereas those of C₁₂PPh‐MMT hybrid fibers decreased slightly. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4535–4545, 2006     

The Effect of Aluminum Ions on the DC Etching of Aluminum Foil

A study has been made of the electrochemical etching of 99.99% aluminum foils at a current density of 50 mA cm^–2in AlCl₃–HCl solutions (1 m Cl^–) at 80 °C. The solutions were made by dissolving metallic aluminum into 1m HCl solution, to give a Cl^– concentration of 1 m. The number density of etch tunnels and the homogeneity of tunnel length decreased, and the mean pit size and its standard deviation increased with increasing Al³⁺ concentration. The results were discussed based on potential transients at a current density of 50 mA cm^–2, current–potential curves at a scan rate of 10 m Vs^–1 and electrochemical impedance spectra.     

Immobilization of a cyclodextrin glucanotransferase (CGTase) onto polyethylene film with a carboxylic acid group and production of cyclodextrins from corn starch using CGTase‐immobilized PE film

Carboxylic acid groups were introduced onto polyethylene (PE) film by radiation‐induced graft copolymerization. Subsequently, the clodextrin glucanotransferase (CGTase) was immobilized on the PE film with a carboxylic acid group. The activity of the immobilized CGTase on PE film was in the range of 0.40–1.04 U/cm² per min. The production of cyclodextrins (CDs) from corn starch was examined using the CGTase‐immobilized PE film. The production ratios of CDs using CGTase‐immobilized PE film was in the following order: α–CD > β–CD > γ–CD. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2451–2457, 2002     

Characteristics of selective adsorption using D-phenylalanine imprinted terpolymer beads

A D-Phenylalanine (Phe) imprinted terpolymer, Polyacrylonitrile-Poly(acrylic acid)-Poly(acryl amide) (Poly(AN-AA-AAm)) bead was prepared by the wet-phase inversion method. Acrylamide (AAm) and acrylic acid (AA) were used as the functional monomer and acrylonitrile (AN) was used as a physical cross linker. The characteristics of selective adsorption by the D-Phe imprinted terpolymer beads were investigated at high concentrations of Phe racemate solution, 1 g Phe/L, and 10 g Phe/L. The adsorption selectivity of the D-Phe imprinted terpolymer beads prepared by anin-situ implanting method reached 0.82 and 0.8 at 1.0 g and 10 g Phe/L racemate solution, respectively, and almost all of the adsorbed D-Phe and about 43% of the adsorbed L-Phe were desorbed by 4% acetic acid. The uptake capacities of the terpolymer beads were maintained for several repeated batches.     

Synthesis and biological activity of phthalimide‐based polymers containing 5‐fluorouracil

The attachment of anticancer agents to polymers is a promising approach towards reducing the toxic side‐effects and retaining the potent antitumour activity of these agents. A new tetrahydrophthalimido monomer containing 5‐fluorouracil (ETPFU) and its homopolymer and copolymers with acrylic acid (AA) and with vinyl acetate (VAc) have been synthesized and spectroscopically characterized. The ETPFU contents in poly(ETPFU‐co‐AA) and poly(ETPFU‐co‐VAc) obtained by elemental analysis were 21 mol% and 20 mol%, respectively. The average molecular weights of the polymers determined by gel permeation chromatography were as follows: M_n = 8900 g mol^?1, M_w = 13 300 g mol^?1, M_w/M_n = 1.5 for poly(ETPFU); M_n = 13 500 g mol^?1, M_w = 16 600 g mol^?1, M_w/M_n = 1.2 for poly(ETPFU‐co‐AA); M_n = 8300 g mol^?1, M_w = 11 600 g mol^?1, M_w/M_n = 1.4 poly(ETPFU‐co‐VAc). The in vitro cytotoxicity of the compounds against FM3A and U937 cancer cell lines increased in the following order: ETPFU > 5‐FU > poly(ETPFU) > poly(ETPFU‐co‐AA) > poly(ETPFU‐co‐VAc). The in vivo antitumour activities of all the polymers in Balb/C mice bearing the sarcoma 180 tumour cell line were greater than those of 5‐FU and monomer at the highest dose (800 mg kg^?1). © 2002 Society of Chemical Industry     

Fabrication of Patterned Inorganic–Organic Hybrid Film for the Optical Waveguide by Microfluidic Lithography

Inorganic–organic hybrid materials for the optical waveguide were synthesized by the sol–gel process starting from the acid-catalyzed solutions of phenyltrimethoxysilane, methyltriethoxysilane, and tetraethylorthosilicate. The control of the refractive index in the organically modified silicate films was achieved by varying the content of phenyltrimethoxysilane incorporated as a refractive index modifier. A single spin-coating with the precursor solution produced a crack-free buffer layer of 22-μm thickness with a dense microstructure. For the fabrication of the patterned guiding layer on top of the buffer layer, the microfluidic lithography method was used. The patterned microlines of the linewidth of 20–35 μm with a sharp edge definition could form by filling the precursor solutions into the microchannels associated with the polydimethylsiloxane microfluidic device. The patterned guiding layer was optically transparent as similar as the bare quartz glass at the wavelength above 500 nm and had a low propagation loss of 0.77 dB/cm at 1310 nm.     

Aqueous dispersion of polyurethane anionomers from H12MDI/IPDI,PCL, BD,and DMPA

Polyurethane anionomer dispersions were prepared from hydrogenated diphenylmethane diisocyanate (H₁₂MDI) or isophorone diisocyanate (JPDI), poly(caprolactone) (PCL) diol, 1,4-butane diol (BD), and dimethylolpropionic acid (DMPA). Upon neutralization of the DMPA with triethylamine (TEA), the NCO-terminated polyurethane (PU) ionomers were self-emulsified by adding water, followed by chain extension using triethylenetetramine (TETA) in aqueous media. Polyurethanes from H₁₂MDI showed coarser dispersion and better tensile properties over those from IPDI. Polyurethanes prepared by the one-shot method had better dispersion and tensile properties over those by the two-shot method. When some of the PCL diol was replaced by DMPA or BD, tensile strength increased and ductility decreased due mainly to the increased chain rigidity and intermolecular forces. © 1994 John Wiley & Sons, Inc.     

Effects of estrogen-induced hyperlipidemia on the erythrocyte membrane in chicks

The effects of estrogen-induced hyperlipidemia on plasma lipid peroxidation, fatty acid composition and osmotic fragility of erythrocytes in chickens were studied. Young male chickens implanted with estrogen for three wk developed a marked hyperlipidemia. Plasma levels of triglyceride, cholesterol and phospholipid were elevated 68-, four- and 24-fold, respectively, over controls. There was also a two-fold increase in plasma lipid peroxidation measured by the thiobarbituric acid test. Vitamin E supplement (1,000 IU/kg diet) reduced the plasma lipid peroxidation to the control level, but had no effect on the plasma lipid content. Estrogen-induced hyperlipidemia resulted in changes in the fatty acid composition of membrane lipids of erythrocytes. The major changes were an increase in oleic acid from 10.0% to 14.2% and a decrease in linoleic acid from 31.3% to 26.0%. The erytrocytes with an altered membrane fatty acid composition were found to have an increased osmotic fragility. It was apparent that there was a direct correlation between the oleic acid content and the osmotic fragility of erythrocytes.     

A visual study on flame behavior in tone-excited non-premixed jet flames

A visualization study on the effect of forcing amplitude in tone-excited jet diffusion flames has been conducted. Visualization techniques are employed using optical schemes, which are a light scattering photography. Flame stability curve is attained according to Reynolds number and forcing amplitude at a fuel tube resonant frequency. Flame behavior is globally grouped into two from attached flame to blown-out flame according to forcing amplitude; one sticks the tradition flame behavior which has been observed in general jet diffusion flames and the other shows a variety of flame modes such as the flame of a feeble forcing amplitude where traditionally well-organized vortex motion evolves, a fat flame, an elongated flame, and an in-burning flame. Particular attention is focused on an elongation flame, which is associated with a turnabout phenomenon of vortex motion, and on a reversal of the direction of vortex roll-up. It is found that the flame length with forcing amplitude is the direct outcome of the evolution process of the formed inner flow structure. Especially the negative part of the acoustic cycle under the influence of a strong positive pressure gradient causes the shapes of the fuel stem and fuel branch part and even the direction of vortex roll-up to dramatically change.     

Desulfurization in a plate-type gas-lift photobioreactor using light emitting diodes

Hydrogen sulfide gas was removed in a 2-dimensional gas-lift reactor by the photosynthetic microorganismChlorobium thiosulfatophilum using light emitting diodes (LEDs) as a light source. LEDs saved light energy by 99% compared with the incandescent light source. The plate-type gas-lift reactor removed hydrogen sulfide five times better per unit mg of protein, and performed two times better in the maximum performance per unit luminous flux, compared with cylindrical fermentors.