Materials Science Forum Vols. 809-810

Abstract: The impact on the adsorption of Zn²⁺of these factors, initial concentration, modification time, reaction time vermiculite dosage, reaction temperature and pH having, and absorption mechanism are studied . The results show that: microwave modification time 30s, reaction time 40min, modified vermiculite dosage 8g/L, reaction temperature 30°C, reaction pH 6, Zn²⁺ adsorption rate can reach 97.91%, adsorption isotherms of Zn²⁺ by microwave modified vermiculite show that the adsorption equilibrium is consistent with Langmuir curves, correlation coefficient reached to 0.997 at room temperature.

Abstract: The microenvironment has been shown to regulate cellular functions including cell growth, differentiation, proliferation, migration, cancer development and metastasis. However, the underlying mechanism remains largely unclear. It has been reported that tension force is a key issue for osteogenesis of human mesenchymal stem cells (MSCs) and osteoblasts. In the present study, fibronectin film covered on glass substrate was made into square-shaped micro patterns. Osteoblasts cultured on this geometric substrate first located at the edge of the square. Next day the cells extended to the whole square. The results showed that geometric cues can control the growth of osteoblasts. Possible explanation is that the edge of the square provides higher tension force to the cell. These findings demonstrate that tension force from geometric shape is a positive signal for osteogenesis of osteoblasts and bone remodeling.

Abstract: Through an alkylation reaction under alkaline conditions, isobutyl was introduced to chitosan to form isobutyl-chitosan. Isobutyl-chitosan-Ca (II) complex was synthesized at pH 6.0 by a reaction of isobutyl-chitosan and calcium chloride. The structure of isobutyl-chitosan-Ca (II) complexes was characterized by ultraviolet-visible diffuse reflectance spectrum (UV-Vis) and FT-IR spectrum, and the content of calcium was measured by inductively coupled plasma-optical emission spectrometry (ICP-OES). The FT-IR spectra of isobutyl-chitosan and chitosan showed that structure of isobutyl-chitosan-Ca (II) complexes was obviously different with isobutyl-chitosan. Results of UV spectra showed that the maximum absorption of isobutyl-chitosan and isobutyl-chitosan-Ca (II) were at 310 nm and 324 nm, respectively. The content of calcium was 1.6026%, measured by ICP-OES.

Abstract: The surface topography and biocompatibility of titanium mesh treated with inositol hexakisphosphate (IP6) was studied. At high concentration of IP6, micro-grooved titanium surface with width of ~ 8 μm was formed. Then, calcium phosphate coating was deposited on the micro-grooves by a second hydrothermal treatment. Furthermore, cell culture results showed that micro-grooved surface could guide cell elongation and stretching along the grooves. Calcium phosphate modified micro-grooved titanium surface enhanced the cell viability compared with the unmodified surface. Therefore, IP6 modification may be a good candidate for improving the biocompatibility of titanium implants.

Abstract: A tungsten-containing mesoporous molecular sieve SBA-15 (W-SBA-15) was synthesized directly by the hydrolysis of tetraethylorthosilicate and ammonium tungstate with triblock copolymer EO₂₀PO₇₀EO₂₀ (P123) as template in acidic medium. The W-SBA-15 was characterized by XRD, N₂ adsorption/desorption, UV-Vis spectroscopy, Raman spectroscopy and ICP-AES spectrometry. The W-SBA-15 exhibited high catalytic activity for the hydroxylation of cyclohexene with hydrogen peroxide (H₂O₂) as oxidant. The complete conversion of cyclohexene into glycol monoethers with very high selectivity (92.6%) were obtained over the W-SBA-15 catalyst.

Abstract: Biomedical transparent poly(carbonate-urethane) elastomers were synthesized by melting pre-polymer method, using 4,4’-methylenebis (cyclohexyl isocyanate)(H12MDI) and chain extender (butadiene)(BDO) as hard segment, poly(1,6-hexanediol) carbonate diols(PCDL) as soft segment, and dibutyltin dilaurate as catalyst.The effects of molar ratio of the reactants on mechanical properties of PCU were studied and the relationship between micro-phase separation structure and properties was analyzed by the contact angle determination, total reflection fourier transform infrared spectrography(ATR-FTIR), differential scanning calorimeter(DSC),gel permeation chromatograph (GPC), mechanical property test. The comparative analysis was made between the prepared material and commercial medical polyurethane materials, showing the prepared poly(carbonate-urethane) elastomers was better in mechanical properties. As a elastic biomedical material, it has a great potential for developments and applications in biomedical materials.

Abstract: Chitosan/Heparin (CS/Hep) modified temperature sensitive hydrogels of γ-PGA were prepared by layer-by-layer self-assembly process. The chemical structure of the hydrogels and the surface elements were characterized by FT-IR spectrograph, XPS and TBO staining. The biocompatibility of the CS/Hep modified ploy (γ-PGA-co-NIPAAm) hydrogels were analyzed by the experiments of cell adhesion, cell proliferation and low-temperature induced cell detachment. A temperature-sensitive hydrogels carrier that could specific binding to growth factor was prepared in this research.

Abstract: An oxide-alumina-silica coating which would to improve the oxidation resistance of carbon fibers was prepared by sol-gel method. XRD and SEM were used to characterize the surface appearance and phase transition about the carbon fibers with oxide-alumina-silica coating. The oxidation resistance of carbon fibers was also analyzed with the DSC-TG and the isothermal oxidation experiment. It was shown that the antioxidant properties of the carbon fibers with oxide-alumina-silica coating improved significantly. The concentration of precursor sol had an influence on the coating of carbon fibers and the antioxidant properties of the carbon fibers with oxide alumina silica coating increased 300°C compared to uncoated ones.

Abstract: The TiN ceramic films were deposited on Si (100) substrates with Al and Ti buffer layers by direct current reactive magnetron sputtering in the mixture gas atmosphere of argon and nitrogen. X-ray diffraction (XRD), Raman spectroscopy, scanning electronic microscope (SEM), nanohardness test and ultra violet-visible-near infrared (UV-VIS-NIR) spectrophotometer were employed to analyze the structure, mechanics and optical characteristics of the TiN films respectively. Analyses of XRD and Raman showed that all the TiN films deposited on Al and Ti buffer layers with TiN (111)-preferred orientations had polycrystalline structures, and the TiN film deposited on Ti buffer layer had a better crystallinity, smaller surface roughness, higher hardness and larger elastic modulus than those of the TiN film deposited on Al buffer layer. Moreover, the reflectivity of the Ti/TiN film became higher than Al/TiN film above λ=645 nm. At λ=1200 nm, the Ti/TiN film showed the maximum reflectivity of 81.8%. These conclusions also showed that the metal multilayer TiN films have important application and research prospect in terms of solar control coatings or resistance to high temperature in building coating material.

Abstract: NiCr/ZrO₂ gradated coatings were obtained on C45 carbon steel by high velocity arc spraying and micro-plasma spraying to improve the mechanical and thermal behaviors of the carbon steel. Scanning electronic microscope (SEM) and X-ray diffraction (XRD) were employed to characterize the microstructure of the prepared composite coatings. Mechanical properties including hardness and bonding strength were also evaluated by microhardness tester and electron tensile tester. The thermal shock behaviors were investigated by quenching the coating samples in cold water from 900 °C and 1100 °C, respectively. The oxidation of NiCr/ZrO₂ gradated coating and C45 carbon steel substrate were carried out for up to 108 hours in air atmosphere at 1100°C. The oxidation behaviors were investigated after detailed examinations by thermal gravimetric analysis. Experimental results indicate that NiCr/ZrO₂ gradated coating exhibit a much higher hardness and high temperature oxidation behavior than the substrate. The bonding strength and thermal shock behavior of NiCr/ZrO₂ are superior to pure ZrO₂ coating, which could be mainly attributed to the NiCr intermediate graded layer due to the microstructure improvement and relaxation of residual stress concentration.