Advanced Materials Research Vols. 875-877

Abstract: Due to the absence of the functional group in the poly (p-xylylene) (PPX) based tube, there is limitation of its application such as a catalyst supporter. In this paper a functional tube with a modification of the PPX tube by coating with polyacrylonitrile (PAN) was successfully prepared and its dielectric constant was measured. The results show that the PAN coated PPX tube has an obvious dielectric relaxations, which has no great different with that of a pure PAN film.

Abstract: A new type of polyaspartic acid ester (PAE) was synthesized by double alkyl malay acid ester and bis-(p-aminocyclohexy) methane (PACM) via a Michael addition reaction. The Fourier transform infrared spectrometer shows the reaction can take place in room temperature. The dynamics of the reaction were investigated by mercaptan-iodine titration analysis method at 57°C and 67°C. The results showed the reaction order between double alkyl malay acid ester and bis-(p-aminocyclohexy) methane (PACM) was three. The solvent free polyaspartic polyurea coating was developed with the synthesized resin and the properties were tested with good results.

Abstract: Renewable resourced green biocomposites are currently receiving much attention due to their environmental advantages. Therefore, the aim of this research is study the effect of fiber surface treatment on the mechanical properties of polylactic acid (PLA) biocomposite in order to produce a green biocomposite. Experiments were conducted by surface treatment of empty fruit bunch fiber using two methods, sodium hydroxide and silane. Both treated and untreated fibers were then melt compounded with PLA and mechanical properties of the biocomposite was studied. The results showed that silane treatment improved the reinforced biocomposite mechanical properties such as tensile strength by 33% and flexural modulus by 44% compared with untreated fiber reinforced biocomposites. This is due to the silane functional groups that act as a bridge between the PLA and fiber.

Abstract: The hydration degree of fly ash and the calcium hydroxide (CH) content were measured. Combined with the equilibrium calculation of cement hydration, a new method for assessment of the hydration degree of cement in the fly ash-cement (FC) pastes based on the CH content was developed. The results reveal that as the fly ash content increase, the hydration degree of fly ash and the CH content decrease gradually; at the same time, the hydration degree of cement increase. The hydration degree of cement in the FC pastes containing a high content of fly ash (more than 35%) at 360 days is as high as 80%, even some of which hydrates nearly completely. The effect of water-cement ratio to the hydration degree of cement in the FC pastes is far less distinct than that of the content of fly ash.

Abstract: In this work, TiO₂(B) nanotubes with uniform diameter were prepared by the simple route of hydrothermal synthesis, and graphene nanosheets were added to form TiO₂(B)/graphene nanocomposites, the two kinds of materials were comparatively studied as anode materials. The morphology and crystal structure were studied by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The electrochemical performance was evaluated by galvanostatic chargedischarge tests. The results show that the nanocomposite electrode material has good electrochemical performance due to the contributions of graphene. At the current density of 50mA/g, the capacity of TiO₂(B)/graphene is 135.8 mAh/g, and the coulombic efficiency is 61.8%, after 10 charge-discharge cycles it still retains 113.2mAh/g . However, TiO₂(B) anode reduces rapidly to 65.6 mAh/g.

Abstract: Jackfruit (JS)-konjac glucomannan (KGM) blend films were prepared using different concentrations of JS, KGM and glycerol. Their mechanical properties were determined. All the films exhibited significantly higher values of tensile strength and elongation at break than those of neat JS films. The values varied considerably depending on KGM and glycerol content. Quercus infectoria extract was embedded into the films and its release characteristics were controlled by changing the initial KGM content. This study suggests that the blend film has a potential use for advanced controlled release of bioactive extracts.

Abstract: Removed at authors request

Abstract: The potential of rice husk-based activated carbon as an alternative low-cost adsorbent for the removal of Pb (II) ion from aqueous solution was investigated. Rice husk-based activated carbon was prepared via chemical activation process using NaOH followed by the carbonization process at 500°C. Morphological analysis was conducted using field-emission scanning electron microscope /energy dispersive X-ray (FESEM/EDX) on three samples, i.e. raw rice husk, rice husk treated with NaOH and rice husk-based activated carbon. These three samples were also analyzed for their C, H, N, O and Si contents using CHN elemental analyzer and FESEM/EDX. The textural properties of rice husk-based activated carbon, i.e. surface area (253 m²/g) and pore volume (0.17 cm²/g), were determined by N₂ adsorption. The adsorption studies using rice husk-based activated carbon as an adsorbent to remove Pb (II) ion from aqueous solution were carried out at a fixed initial concentration of Pb (II) ion (150 ppm) with varying adsorbent dose as a function of contact time at room temperature. The concentration of Pb (II) ion was determined by atomic absorption spectrophotometer (AAS). The removal of Pb (II) ion from aqueous solution increased from 35 % to 82 % when the amount of rice husk-based activated carbon was increased from 0.05 g to 0.30 g. The equilibrium data obtained from adsorption studies was found to fit both Langmuir and Freundlich adsorption isotherms.

Abstract: Reaction of an isocyanide with an iminium ion intermediate, formed by reaction between an electronpoor 2-hydroxybenzaldehyde derivative and a secondary amine in the presence of silica nanoparticles proceeds smoothly at room temperature to afford benzo [b] furan derivatives in high yields.

Abstract: Irreversible crystal-to-crystal transformation of 3D lead (II) coordination polymer with the ligand 1H-1,2,4-triazole-3-carboxylic acid (HL), [Pb (L)(μ_1,1-NCS)(H₂O)]_n (1) to 3D supramalecular compound [Pb (L)(μ₂-I)]_n (2) by solid state anion-replacement have been studied. Structural determination of compound 2 reveals the Pb (II) ion is five coordinated with hemidirected geometry, bonded to one nitrogen atom, two oxygen atoms from the Lˉ ligand and two iodide ions. The irreversible solid state structural transformation of compound 1 to compound 2, by anion-replacement processes under mechanochemical reaction have been verified by PXRD measurements. Nanoparticles of compound 1 was synthesized by sonochemical process and characterized by scanning electron microscopy (SEM), powder X-ray diffraction, IR spectroscopy and elemental analyses. The SEM images showed that no morphology change occur during this solid state anion-replacement.