Advanced Materials Research Vols. 418-420

Abstract: The M3 type high speed steel billets with / without Nb addition were prepared via spray forming. The effects of cooling rate and Nb on the microstructures and property of the M3 type high speed steel were investigated. The results show that the as-cast steels contain coarse primary dendrites and M₂C eutectic carbide, but the equiaxed grains and fine carbides are formed in the spray-formed steels. It can be seen that carbide precipitation and grain growth were suppressed by high cooling rate. The Nb additions can change the types of primary carbides. The solidified carbide microstructure was effectively changed from M₂C to M₆C type during the cooling of hot spray-formed billet. Niobium improves the microstructural thermostability of the M3 type high speed steel during heat treatments.

Abstract: In this paper Ag nanocaps arrays were fabricated with a seed-mediated growth method by depositing Ag films on top of self-assembly close-packed monolayer of SiO2 nanoparticles. Their surface morphologies and optical properties were characterized using TEM, SEM and UV-Vis spectroscopy. Malachite green (MG) was chosen as analyte, the Surface-enhanced Raman Scattering (SERS) spectra of MG adsorbed on Ag nanocaps arrays were investigated. The enhancement factor was estimated to be as large as 4.5×10⁹. These results revealed that these Ag nanostructures are promising for SERS applications in trace measurement and analysis of biological molecules.

Abstract: The study of polyurethanes are of continuing interest due to their excellent physical properties. In this study, the reaction kinetics and polymerization conditions in two-step process of toluene diisocyante (TDI) and polypropylene glycol (PPG) with organo-tin mixed catalyst were investigated by di-n-butylamine back-titration. It was showed that the reaction obeyed the second-order equation of step-growth polymerization, the rate constants of TDI and PPG reaction at 50, 60 and 70°C were 0.0922, 0.3373 and 0.5828 kg•mol-1•min-1，respectively. The activation energy obtained from the result was 71.63 kJ•mol-1. The number average molecular weight (Mn) and molecular-weight distribution (Mw/Mn) of the polyurethane were 45175 and 1.53, respectively, and the content of hydrogen bonding in the N-H group from Fourier transform infrared spectrum (FTIR) was 80.75%, which manifested that the large amount of N-H were present in hydrogen bonding.

Abstract: A simple polyacrylamide gel method was used to prepare strontium titanate (SrTiO₃) nanoparticles. X-ray diffraction (XRD) analysis reveals that single-phase SrTiO₃ can be synthesized at a calcination temperature of 550 °C. Scanning electron microscope (SEM) observation shows that the as-prepared SrTiO₃ particles are regularly shaped like spheres and highly uniform in size with an average diameter of ~55 nm. Ultraviolet (UV)-visible diffuse reflectance spectrum analysis indicates that the bandgap of the sample is 3.23 eV. The Brunauer-Emmett-Teller (BET) specific surface area of the sample is measured, by the N2 adsorption-desorption technique, to be 26.4 m²•g⁻¹. The photocatalytic experiments reveal that the SrTiO₃ nanoparticles can effectively degrade various dyes including congo red (CR), rhodamine B (RhB), methyl orange (MO), and methylene blue (MB) under UV irradiation.

Abstract: The heat-press bonding technology of water proof and breathable fabrics with thermoplastic adhesives will play an important role in the processing of stitchless apparels, they will influence not only the stiffness and the processability, but also influence the function and the quality of stitchless apparels. This study will analyze the influence factor about the processability through the test index of the breaking strength. The results showed that pressing time was one of most easily controlled technology in stitchless apparels production.

Abstract: Artificial lung also called as oxygenator which performs a function of exchanging O2 and removing CO2 from blood. Due to its good performance at the exchange area, oxygenation, etc, hollow fiber membranes have become the main research direction of artificial lung. Polypropylene (pp) hollow fiber membranes made by the melt-spinning and cold-stretching methods (MSCS) in this study. Through the research on the membrane manufacture process and technology optimization to prepare suitable membrane for artificially lung. The performance of membrane was affected by the melt-draw ratio and spinning temperature, annealing temperature, and the proportional relations of cold stretch with hot stretch. The results of the study show that improve melt-draw ratio, select the appropriate annealing conditions and the reasonable ratio of hot stretch with cold stretch can effectively increase the air flux of pp hollow fiber membrane.

Abstract: Collagen/cellulose films were made by the blend solutions of collagen, cellulose in this paper. To begin with, collagen and cellulose was dissolved in 1-allyl-3-methylimidazolium chloride ([Amim]Cl）. The structure of the blend films was characterized by FTIR and XRD. The effects of weight ratio between the two polymers on light transmittance, tensile strength, elongation at break and water absorption of the film were studied. The results showed that there were strong interactions and good compatibility between collagen and cellulose in the film and the polymers have strongest interactions at the mixing ratio of 5:5. The blend films possess better properties such as mechanical and water absorption properties than those made of single polymer.

Abstract: Stop-motion animation is an ancient form of animation. After nearly a century of development, the material application of stop-motion animation becomes diversified. Currently, however, the well-known stop-motion animations are produced by clay materials. Clay materials play an important role in the application of stop-motion animation. Clay materials, because of its expressive ability demonstrated by its strong plasticity, enables the roles it has shaped lively and characteristic and the stop-motion animation to be full of affinity and vitality. This paper starts from the properties and material expressive ability of clay materials, combined with the short clay animation film named Daffodil to have a study and analysis of the vitality demonstrated by clay materials.

Abstract: H₃PW₁₂O₄0/Ce_0.1Ti_0.9O₂ and imidazolium salt ionic liquid catalysts were prepared and applied to the direct synthesis of dimethyl carbonate (DMC) from methanol and carbon dioxide. The effect of reaction temperature, reaction time, pressure of carbon dioxide and amount of H₃PW₁₂O₄0/Ce_0.1Ti_0.9O₂ in the presence of ionic liquid are discussed. The results showed that H₃PW₁₂O₄0/Ce_0.1Ti_0.9O₂is an effective catalyst. The high selectivity and higher yield of DMC were achieved. The combination of imidazolium salt and H₃PW₁₂O₄0/Ce_0.1Ti_0.9O₂ could evidently improve the yield of the product. The maximum DMC yield reached up to 12.98 % in the presence of EMImCl at 140°C and 2.4 MPa.