Key Engineering Materials Vol. 831

Abstract: Polyurethane (TPU)/polypyrrole (PPy) blends were successfully prepared by the solution blending process with different contents of reduce graphene oxide (rGO). The controlled synthesis of PPy/rGO composites was reported by varying graphene contents of 10, 20, 30 and 40% w/v. Fourier transform infrared (FTIR) and Scanning electron microscope (SEM) were used to characterize their structures and morphologies. The SEM images show the growing of PPy along the surface of graphene. FTIR illustrated that the PPy/rGO composites were in the doped state. The electrical conductivity of PPy/rGO composites with the concentration of graphene at 40% was about 30 times higher than that of pure PPy. Thermogravimetric analyzer (TGA) thermograms indicated that the PPy/rGO composites have better thermal stability than pure PPy.

Abstract: Ultra-nanocrystalline diamond films were prepared by a microwave plasma-enhanced chemical vapor deposition reactor using CH₄/H₂ gas mixture with a power as low as 650 W. The effects of CH₄ concentration on nanostructure of the films and gas-phase species in plasma were investigated. The CH₄ concentrations of 1.5%, 3.0%, 3.5%, and 4.0% were used and balanced with H₂ to a total flow rate of 200 sccm. Morphology and composition of the films were characterized by SEM, Raman spectroscopy and Auger spectroscopy. The gas-phase species and electron density in the plasma were explored by optical emission spectroscopy and plasma-impedance measurement. The increasing CH₄ concentration from 1.5% to 4.0% increased C₂H_x species and decreased electron density. Phase of the film transform from nano- into ultranano- diamond phase but the growth rate revealingly decreased from 300 to 210 nm/h. Raman spectra indicate the higher CH₄ concentration promted phase of the film transiton from NCD to UNCD. While Auger spectra revealed that UNCD film deposited with 4.0%CH₄ was composed of 90.52% diamond phase but only 9.48% of graphite phase. The relation between phase transformation of the films and growth mechnism controlled by gas-phase species in the plasma will be dissused.

Abstract: Titanium dioxide is a widely-investigated semiconductor photocatalyst due to its wide availability and low cost. Although it has been successfully used in the photocatalytic treatment of various organics in wastewater, it remains a challenge to modify its structure to achieve enhanced catalytic properties at a wider light spectrum. Doping with transition metals was seen to narrow its optical band gap yet synthesis routes have been largely limited to the use of high-end equipment. Herein we demonstrate the use of a simpler one-pot approach to synthesize nanoporous arrays of silver-doped titanium dioxide nanotubes (Ag-TiNTs) by double anodization of titanium sheets. The synthesized Ag-TiNTs have an average inner diameter of 58.68 nm and a wall thickness of 16.46 nm. ATR-FTIR spectroscopy revealed its characteristic peaks attributed to O-Ti-O bonds. Silver doping increased the lattice volume and crystallite size of anatase with a corresponding decrease in the degree of crystallinity due to the introduction of impurity Ag atoms in its tetragonal structure. Silver was homogeneously distributed across the nanotube surface at an average loading of 1.41 at. %. The synthesized Ag-TiNTs were shown to have a superior photoelectrocatalytic activity in degrading C.I. Basic Blue 9 under UV illumination with a pseudo-first-order kinetic rate of 1.0253 x 10^-2 min^-1. Most importantly, the Ag-TiNTs are photoelectrocatalytically-active even at a low Ag loading.

Abstract: Humic acid - functionalized silver nanoparticles (HA-AgNPs) were successfully synthesized and used to detect Cu (II) ions in aqueous solutions. The HA-AgNPs was shown to have an average hydrodynamic diameter of 101.4 nm and a polydispersity index of 0.447. The absorbance spectra of HA-AgNPs showed the characteristic local surface plasmon resonance (LSPR) peak of AgNPs at 408.3 nm. Addition of Cu (II) in the HA-AgNPs led to their agglomeration as evidenced by the change in their surface morphology and their corresponding optical absorbance spectra. The synthesized HA-AgNPs showed a strong linear response for Cu (II) concentrations in the range of 0.00 – 1.25 mM with a limit of detection (LoD) of 4.4428 ± 0.1091 mg L^-1, a limit of quantification (LoQ) of 14.8094 ± 0.3636 mg L^-1, and a limit of blank (LoB) of 0.1214 ± 0.0065 mg L^-1. Statistical analysis showed that this calibration curve could be used to quantify Cu (II) concentrations within a 95% confidence level. Furthermore, HA-AgNPs was found to be selective for Cu (II) detection based on the selectivity study against common metal ions found in drinking water. This shows that the synthesized HA-AgNPs can be used as an environment-friendly colorimetric nanosensor for rapid and point-of-need quantification of Cu (II) ions in aqueous media.

Abstract: An effort to improve electrical property of Polypropylene (PP)/Clay nanocomposite was conducted. Carbon black (CB) was introduced into PP/Clay to enhance that property as required for conductive polymer composites (CPCs) application. The compositions of CB on PP/Clay were varied at 3, 5, and 7 percent hundred resin (phr). In this research, all composites were prepared by melt mixing using an internal mixer at 222 °C, 83 rpm, and 10 minutes. A compatibilizer, PP-grafted-Maleic Anhydride (PP-g-MA), was used to facilitate dispersion of clay layers and CB particles on PP matrix. The electrical property of composite was evaluated from their surface resistivity using insulation tester. Meantime thermal-oxidative stability property was analyzed from oxidative induction time (OIT) data using Differential Scanning Calorimetry (DSC) instrument. The presence of CB dramatically decreased surface resistivity of PP/Clay from 6.98 x 10¹³ ohm to 7.35 x 10⁶ ohm by adding CB 7 phr. OIT of PP/Clay dropped 155% compare with neat PP. On the other hand, the addition of CB 7 phr into PP/Clay improved OIT of PP/Clay up to 22 %. The interlayer structure of clay was investigated using X-ray Diffraction (XRD) to find out the synergistic effect between clay and CB. Actually, clay interlayer spacing did not change due to the addition of CB.

Abstract: The present study investigated effects of fabric parameters on the water vapor transmission of socks fabric, which was measured by the cup method. It was found that the water vapor transmission of fabric was negatively proportional to the content of cotton and yarn count, before washing. Meanwhile, washing was found to increase the water vapour transmission.

Abstract: Plasma technology provides an effective way to modify the surface of polymeric materials and thus improve the physicochemical properties of this material. This study was a preliminary study in exploring the application of plasma technology in the surface modification of silk fiber. Experimental results revealed that the dyeability of silk fabric with acid dye was improved after plasma treatment.

Abstract: Hand feel properties are importance factor of quick dry inner wears. This study aims to evaluate the hand feel properties of women’s quick dry inner wears in the market (three commonly found products in the market) by studying their relative hand value. The relative hand value was measured according to the standard of AATCC-202. Experimental results revealed that the three quick dry inner wears performed differently in the hand feel. The experimental results were discussed comprehensively in this study.