Advanced Materials Research Vols. 93-94

Abstract: Following a short overview of application of cyclodextrins (CDs) in textile finishing methods for the permanent fixation of CDs onto texiles and approaches to their quantitative analysis are reviewed. A new analytical method, based on the inclusion complexation of ferrocene, and a quantitative study, utilizing this method, on the covalent fixation, washing fastness and formaldehyde release of CD-containing finishes are presented. Ferrocene complexation is proven by Raman spectroscopy and by comparison with maltodextrin. Some of the finishing treatments resulted high yields and permanence against washing. Hydroxypropyl-CD reduced formaldehyde release and acted possibly as a formaldehyde scavenger. Using “low formaldehyde” crosslinkers ” requirements easily met.

Abstract: Flexible electronics technology can potentially result in many compelling applications not satisfied by the rigid Si-based conventional electronics. Commercially available foils such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) have emerged as the most suitable polymer materials for wide range of flexible electronics applications. Despite the enormous progress which has been recently done on the optimization of physical and mechanical properties of PET and PEN foils, their dimensional stability at the micro-scale is still an issue during patterning of wiring by means of lithography. Consequently, the measurement of in-plane micro-deformation of foil is of great importance for understanding and predicting its thermal, hydroscopic and mechanical behaviour during processing.

Abstract: Mass attenuation coefficients and partial photon interactions have been calculated theoretically at photon energy 60 keV for Bi2O3, PbO and BaO in xRmOn:(100-x)B2O3 glass system, when 30  x  70 (by %weight) using WinXCom. The values of these parameters have been found to significantly change with increasing of RmOn concentration. The variations of mass attenuation coefficients, photoelectric absorption, and coherent scattering were increased, whereas Compton scattering decreased along with increasing composition of glass samples. Those variations are due to photoelectric effect is the dominant interaction in low photon energy region. The use of mass attenuation coefficients to determine effective atomic numbers are also discuss, which found to be increase with the concentration of glass samples. This result reflecting the possibility to use bismuth and barium replaces lead for development of lead-free radiation protecting glass at appropriated photon energy, for leave non-toxically impact to our environment.

Abstract: Reactions of the labile complex (Me3tach)M(CO)3 (Me3tach = 1,3,5-trimethyl-1,3,5-triazacyclohexane; M = W, Mo) with bis(phenylthio)alkanes ( = PhS(CH2)nSPh), (2:3 molar ratio) in CH2Cl2 as solvent (at 35 oC M = W, 0 oC M = Mo) afforded in good yields bimetallic tricarbonyl complexes triply- bridged by bis(phenylthio)alkanes of the type [M(CO)3]2(μ-PhS-(CH2)n-SPh)3 [n = 3 (a), 4 (b), 5 (c), 6 (d); M = W (1), Mo (2)]. These new triply-bridged complexes were characterized by 1H NMR, FT-IR and elemental analysis. Additionally, it has been observed that the thermodynamic stability of some of these new complexes in chlorinated hydrocarbons depends mainly on the nature of the metal center and varies in the order W >> Mo.

Abstract: Effects of carboxymethyl cellulose from papaya peel (CMCp) on the properties of ceramics were investigated. Cellulose was extracted from papaya peels by NaOH and then it was modified by chloro acetic acid to obtain carboxymethyl cellulose. The prepared CMCp was applied as a binder in ceramic slip in order to increase its viscosity. Sodium silicate was also added into the slip for providing a dispersion of slip and protecting the sedimentation of clay particles. Various concentrations of CMCp and commercial CMC (CMCc) (0.05, 0.1, 0.15, 0.2 and 0.25% w/w of dry weight of clays) were added into the slip. Effect of CMC on viscosity of the slip and the ceramic density were studied. The relationship between the ceramic properties such as, shrinkage, porosity, casting rate and bending strength (both green strength and fired strength), and CMC concentration was also observed. As increasing both CMCp and CMCc, viscosity increased while density decreased. The prepared ceramics (green ware and fired ware) added with CMCp were found to have higher strength and lower in %shrinkage than that of adding with CMCc. The thickness of the ceramic wall adding CMCc increased with increasing CMCc concentration, and time in contrast to that of CMCp as the thickness decreased with increasing CMCp concentration. However, the ceramics with addition of CMCp possessed higher strength than that of the commercial one.

Abstract: This work compared properties and catalytic performance of two hybrid photocatalysts, TiO2/RH-MCM-41 and TiO2/TEOS-MCM-41 prepared by loading nanoparticles of TiO2 (10 wt.%) on MCM-41 synthesized with rice husk silica and tetraethyl orthosilicate respectively. The supports and catalysts were characterized by X-ray diffraction, N2 adsorption-desorption, transmission electron microscopy and zeta potential. The photocatalytic activities of the TiO2/RH-MCM-41 and TiO2/TEOS-MCM-41 for the degradation of tetramethylammonium (TMA) in aqueous slurry were similar with a complete conversion after irradiation time of 90 min at pH 7.

Abstract: Silica-coated raspberry-like polymeric particles were synthesized based on the cationic colloidal particles which were prepared by soap-free emulsion polymerization of methylmethacrylate (MMA) in the presence of a cationic monomer, methacryloxyethyltrimethyl ammonium chloride (MOTAC) using azobis(isobutylamidine)hydrochloride (AIBA) as an initiator. The Stöber method has been adopted to coat silica on the surface of these cationic particles. Negatively charged Silica precursors were rapidly hydrolyzed onto the cationic surfaces of colloidal particles. The resulted polymethylmethacrylate-silica(PMMA-silica) core-shell particles were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), which clearly revealed that the PMMA-silica core-shell particles had the raspberry-like structure with 45nm wall thickness. Then, the fabrication of a superhydrophobic particle surface was achieved by coupling reaction of the PMMA-silica core-shell particle surface with nonafluorohexyltriethoxysilane. The water and oil static contact angle on the surface of the submicron-nano particles were 161° and 129°, respectively.

Abstract: We focus on the energy conversion improvement of dye-sensitized solar cells by using poly(ethylene oxide)-multi-walled carbon nanotube (PEO-MWCNT) electrolyte. Compared with the MWCNT-free solar cells, the addition of 0.05 wt.% MWCNTs in the polymer electrolyte results in a dramatic increase of the short-circuit current (Jsc), consequently raising the device performance by approximately 9% under a direct light of the Air Mass 1.5 irradiation at 100 mW cm-2. The role of the conductive carbon materials in the polymer electrolyte have been investigated by means of ionic conductometry, electrochemical impedance spectroscopy and UV-visible spectroscopy. This work demonstrates that MWCNT additives in polymer electrolytes is a convenient yet effective strategy for improving the performance of photovoltaic devices.