Advanced Materials Research Vols. 239-242

Abstract: A novel amphiphlic adsorbent resin of macroporous polystyrene Validamycin A was synthesized via the amination of chloromethylated macroporous crosslinked polystyrene resin using Validamycin A. Its chemical structure was characterized by Fourier transformation infrared spectra and elemental analysis. Its pore structure was determined by nitrogen adsorption-desorption measurements. Test results of swelling ratio in various solvents revealed that the aminated resin was amphiphilic. The resin showed excellent adsorption performance for the amphiphilic organic compounds of pueraia isoflavones in aqueous solution.

Abstract: Thin Cr/C film was synthesized on 4Cr10Si2Mo steel substrates by Plasma Immersion Ion Implantation and Deposition (PIIID). The high-temperature oxidation behavior of Cr/C Coating at 900°C for 100 hours in air atmosphere was investigated. The results show that the Cr/C coating on 4Cr10Si2Mo steel by PIIID process has excellent high-temperature resistance and antioxidant properties. After the oxidation behavior for 100 hours, the surface of coated specimen maintains completely and the Cr/C coating has a good bonding force with substrates. The composition of the oxidation scale and the surface morphology were studied by using XRD and SEM. An uncoated sample and a hard chromium plating sample with same substrate took part in the experiment in same condition for comparing.

Abstract: Crosslinked Carboxymethyl Konjac Glucomannan(CMKGM) with substitution degrees ofcarboxymethyl group（DS）0.265, 0.457 and 0.586 were prepared through reaction of monochloroacetic acid, konjac glucomannan(KGM) and epichlorohydrin and used to adsorb Cu(II) from the aqueous solutions of copper nitrate. The effects of pH, adsorbent dose, initial concentration of Cu(II), adsorption time and temperature on adsorption capacity were investigated. The results showed that adsorption capacity increased with an increasing DS of the carboxymethyl groups. Equilibrium adsorption time was 20 min or so and was independent on DS. The adsorption followed Langmuir isotherm equation. Ligand ion adsorption between carboxymethyl group and Cu(II) was thought to be predominate in the process of adsorption according to the relationship between DS and thermodynamic parameters. CMKGM can be used as cheaper and more effective adsorbents.

Abstract: This research attempts to test the mechanical properties of calcium oxide-phosphorous slag powder cementing material under autoclave curing condition. X-ray diffraction, scanning electron microscope-energy dispersion scanner and differential scanning calorimetry-thermogravimetry were adopted to characterize the performance of the hydration products and microstructure of phosphorous slag powder cementing material autoclaved product. The research findings showed that under the condition of autoclave curing, doping calcium oxide would activate preferable property of hydration and hardening of phosphorous slag powder cementing material, and the best strength of the cementing material would be achieved with optimal doping of 15% (in mass) compound calcium oxide. With the effect of the alkaline activation of calcium oxide, there mainly remained the calcium silicate hydrate gel and Al-calcium silicate hydrate in hydration products of phosphorous slag powder cementing material. Excess calcium oxide made alkalinity of calcium silicate hydrate gel change from low to high, thus leading to the decline of mechanical performance of autoclave products.

Abstract: Mesoporous TiO₂ microspheres with a combination of large surface and high crystallinity were fabricated by an ultrasonic-hydrothermal method with Octadecylamine as a structure-directing agent and tetrabutyl titanate as a precursor. The mesoporous materials were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), N₂ adsorption–desorption measurements, and UV–visible diffuse reflectance spectroscopy (UV-vis). Low-angle XRD and TEM images indicated that the disordered wormhole-like mesoporous architecture of TiO₂ microspheres with diameters of about 200-400 nm were actually formed by agglomerization of nanoparticles with an average size of about 10nm. The analysis from N₂ adsorption–desorption isotherms showed that the surface area of mesoporous sample was 204.7 m²g^-1, with a pore size of 4.3 nm and pore volume of 0.263 cm³g^-1 after calcined at 673 K.

Abstract: α-FeOOH nanorods were fabricated via a one-step hydrothermal approach using iron nitrate hydrate (Fe(NO₃)₃·9H₂O) as iron source, cetyltrimethylammonium bromide (CTAB) as a template and acetic acid (CH₃COOH) solution as solvent. XRD, SEM, TEM, and TGA were applied to characterize the samples. The as-prepared α-FeOOH nanorods are around 50 nm in diameters and 1 µm in length. The aspect ratio is 20. The XRD and TEM results indicated that both CTAB and CH₃COOH were crucial for the formation of α-FeOOH nanorods. The heat treatment at the temperature of 250°C led to the transformation of α-FeOOH to α-Fe₂O₃, and the crystal phase transformation was completed at 340°C. The lower transformation temperature compared to bulk α-FeOOH could be attributed to the decreased size of the as-prepared sample.

Abstract: TiN coatings were deposited on AISI M2 high-speed-steel (HSS) substrates by multi-arc ion plating technique. The thickness of substrate was 1.0 mm and five thicknesses of TiN coatings were 3.0, 5.0, 7.0, 9.0 and 11.0 μm, respectively. X-ray diffraction (XRD) has been used for measuring residual stresses. The stresses along five different directions (Ψ=0°, 20.7°, 30°, 37.8° and 45°) have been measured by recording the peak positions of TiN (220) reflection for each 2θ at different tilt angles Ψ. Residual compressive stresses present in the TiN coatings. Furthermore, the results revealed that the value of the residual stresses in TiN coatings was high. While the coatings thickness changed from 3 to 11 μm, the residual stresses varied from -3.22 to -2.04 GPa, the intrinsic stresses -1.32 to -0.14 GPa, the thermal stresses -1.86 to -1.75 GPa. The residual stresses in TiN coatings showed a nonlinear change. When the coatings thickness was about 8 μm, the residual stresses in TiN coatings reached to the maximum value.

Abstract: AZ91 magnesium alloy is selected as the matrix metal. SEM, EDS, Tafel and EIS were adopted and spot test was carried out to investigate the influence of pH value, phytic acid concentration, temperature,conversion time on corrosion resistance of conversion coatings. Result shows that process of phytic acid forming is the controlled metal corrosion process and the uneven surface pattern reflects the different chemical properties of two-phase current on magnesium alloy surface, which is implied by the conversion surface. It is proved by the test that pH value is committed the most to the corrosion resistance of the conversion coating, and the next is the phytic acid concentration. It is found that the corrosion resistance of the conversion coating is the best when pH value of the conversion solution is 4.5; The conversion coating has little influence on the cathode reaction dynamics, however, more importantly, it changes the dynamics of the alloy electrode anode solution reaction, therefore, the alloy’s anode current density decreases while the corrosion resistance of magnesium alloy is enhanced.

Abstract: Polyviny alcohol (PVA)/ Titanium dioxide (TiO₂) composite films with diffrernt content of nano- TiO₂were prepared by solution casting method. The structure of the film was characterized by FT-IR,and the water tolerance, viscosity, and light transmission rate of composite membrane were tested. The results showed that Nanometer TiO₂ had strong hydrogen bonding interaction with PVA molecules, and with the increasing additive amount of nanometer TiO₂, water resistance was improved, the viscosity of the composite sol rised, and the rate of UV transmission decreased obviously.

Abstract: Reactive compatibilization between high-density polyethylene(HDPE) and wood-flour was achieved via direct reactive extrusion of maleic anhydride(MAH), initiator, HDPE and wood-flour. Impact rupture surface of the composites was observed by scanning electron microscope(SEM), and its load deformation temperature(HDT) and mechanical properties were tested. Effect of MAH dosage, initiator activity and extrusion temperature on the reactive compatibilization was analysed. The result indicated that the anchoring strength of interface in the composites was obviously strengthened and its HDT, tensile strength, flexural strength, notched impact strength and elongation at break were distinctly improved due to the addition of MAH and dicumyl peroxide(DCP). When the composites were extruded at 180°C, the peak values of its HDT, tensile strength, flexural strength, elongation at break and notched impact strength respectively were 79°C, 34Mpa, 36Mpa, 30% and 10KJ.m^-2, which respectively increased by 10°C, 62%, 33%, 200% and 150% than that of the composites without reactive compatibilization, and when the composites were extruded at 200°C, the peak values of its HDT, tensile strength, flexural strength, elongation at break and notched impact strength respectively were 78°C, 34Mpa, 36Mpa, 24% and 8KJ.m^-2, which respectively increased by 12°C, 55%, 33%, 200% and 100% than that of the composites without reactive compatibilization. In the case of DCP and MAH as compatibilizer, there was an optimum dosage of MAH. The optimum dosage was shifted forward as extrusion temperature increased.