Abstract: Biodegradable polyurethane was synthesized using poly(DL-lactic acid) diol and hydroxytelechelic natural rubber as hydroxyl containing precursor, 1,4-butane diol as chain extender, isophorone diisocyanate and dibutyltin dilaurate as catalyst. Poly(DL-lactic acid) diol was prepared by condensation polymerization of DL-lactic acid using 1,4-butane diol as initiator and stannous octoate as catalyst. Hydroxyltelechelic natural rubber synthesized via oxidative degradation of natural rubber and then reduced carbonyl end group to hydroxyl group. Chemical structure of products was characterized by 1H-NMR. Molecular weight and polydispersity determined by SEC. Thermal properties was characterized by DSC and TGA. Segmented polyurethane show two Tgs and two degradation steps corresponding to natural rubber and poly(DL-lactic acid) segment. Polyurethane containing poly(lactic acid) more than 40%mol are become brittle. This result caused by brittle characteristic of PLA. Moreover, mechanical properties increased as content of PLA increased.
Abstract: Thermoplastic starch (TPS) and TPS/wheat gluten composites were prepared using compression molding. The wheat gluten contents ranged from 0 wt% to 20 wt%. The morphology of the fractured surfaces, thermal decomposition temperatures and mechanical properties of the TPS and TPS/wheat gluten composites were investigated using scanning election microscopy (SEM), thermal gravimetric analysis (TGA) and tensile testing, respectively. The maximum tensile strength of TPS/wheat gluten composites (1.1 MPa) was obtained when 10 wt% of wheat gluten was used. The crosslinking between wheat gluten protein chains caused an increase in the tensile strength of the TPS/wheat gluten composites. The temperature at the maximum weight loss of the TPS/wheat gluten composites was higher than for TPS. Moreover, wheat gluten decreased the water absorption.
Abstract: Room-temperature ferromagnetism was observed in the SiCN films prepared by ion implantation. The result indicates that N ion implantation dosage in the film has great effect on the observed room-temperature ferromagnetism of the films. Along with the increase of ion implantation dosage, the N ions increase and the magnetism enhances. Because of the ion implantation will cause a lot of defects on the surface of SiC films, which will induce a lot of vacancies. The C atoms are replaced by the N ions doped, the concentration of the N ions decides the charges states and spin polarizations of Si vacancy defects. Local magnetic moment is induced because of the spin polarization of the Si vacancy defects, and the films show ferromagnetic properties.Charge states and spin polarizations of silicon vacancy defects can be manipulated by N atoms which induces the ferromagnetism.
Abstract: The electrical conductivity of the molten salts of Na3AlF6-LiF-Sc2O3 system with different compositions was measured at different temperatures by the continuously varying cell constant technique. The main influence factors on electrical conductivity were analyzed. Experiment results showed that the technique of the electrical conductivity measurement is accurate and reliable and the result’s relative error is just 0.67% in comparison with those in relevant literature. With temperature rising, electrolyte conductivity increases at a rate of about 0.03S/cm for 1°C. And we also found that the conductivity increases slightly with the addition of lithium fluoride and adding scandium oxide makes the conductivity decrease slightly and more addition doesn’t cause significant effect. It was proved that the technique can measure accurately the electrical conductivity of aluminium electrolyte and other high-temperature molten salts.
Abstract: The antifungal PVA film was fabricated by addition of the clove oil/β-cyclodextrin (β-CD) inclusion complex into PVA. The migration of clove oil in different food simulation solution (A: 10% ethanol water. B: 50% ethanol water. C: 60% glycerin-water mixture. D: n-hexane) were evaluated by using solution food simulation and then treated with linear regression analysis. The diffusion coefficient was cultivated out by Matlab software. The migration of clove oil which was embedded by β-CD in PVA film was influenced by the quality of food simulation solution to a great degree and the relation among the migration rate was A>B>D>C. The film structure was loosed and the migration gallery was increased by adding clove oil/β-cyclodextrin inclusion complex. The migration amount in simulations was positively correlated with time and diffusion coefficient.This kind antibacterial film can be used in low water activity food system and kept long-term antibacterial action.
Abstract: In this study, liquid crystalline copper phthalocyanine and single walled carbon nanotubes were dispersed in solution to prepare novel composites. Thin films of these composites prepared by solving of the composite in dimetylformamide and then by spin coating the solution onto the substrates were studied by the methods of polarizing microscopy, polarized Raman and optical absorption spectroscopies. It was shown that pure CuPcR4 forms the films with a herringbone arrangement of phthalocyanine molecules within adjacent columns. An addition of carbon nanotubes (0.5-2 wt %) to CuPcR4 leads to formation of the films with edge-on orientation of the molecules. The higher conductivity values were found for the films of phthalocyanine containing SWCNT. The lateral conductivity tends to decrease with the increase of SWCNT concentration from 0.5 to 2 wt %.
Abstract: Multilayered TiN coating was successfully prepared by hollow cathode discharge method. By introduction of the multilayered microstructure, the columnar epitaxial growth of TiN grains was obviously suppressed. The hardness, adhesion performance and wear resistance of the multilayered TiN coating were compared with those of the ordinary TiN coating. The wear resistance of the multilayered TiN coating is much better than that of the ordinary TiN coating. It is due to the multilayered microstructure of the coating that pileups the dislocations and also inhibits the bulk-flaking behavior for the multilayered TiN coating. The morphology analysis of cross section shows that the wear mechanism of the multilayered TiN coating is the micro-area detachment. Moreover, the adhesion of the TiN coating to the substrate is greatly enhanced by the microstructure optimization of the coating.
Abstract: In the article the results of studying of the equipment up-to-date condition and grading bulk construction solids theoretical examining on different fractures especially damp materials of bed, lamellar and stylus forms were obtained. It is shown that operating now plane vibration or drum screens do not satisfy to the process of grading non-metallic materials. The article considers processes of screening bulk material on the spiral vibrating screen. The screen rational parameters, which provide product of the high quality, decreasing of consumed power and increasing of efficiency, were determined. Mathematical model of the spring spiral, a spiral vibrating screen is developed. Let’s study spring spiral in two positions - static and dynamic. In the result of making static and also dynamic models we got dependences for determining the lateral strain of spiral turns. Pre-condition for making the given model is the condition of complete spiral loading with input bulk material providing rational values of screening efficiency and effectiveness. The obtained mathemati-cal model of springing spiral, spiral vibration screen will allow to produce qualitative analysis of work of totally new innovating screen
Abstract: Based on the principle that metamaterials-composite structured materials, in which permittivity(ε)and permeability(μ)are both negative in some frequencice, can be structured with periodically arranged SRRs and thin metallic wires which have negative effective permeability and negative effective permittivity respectively, the circular structure of SRRs was modified and a new split-ring resonator with symmetric structure was proposed. A detailed description of the design and simulation procedure was given simultaneously. According to the pattern of symmetric SRRs, ε and μ were calculated in analytic formula. Furthermore, metamaterials with symmetric SRRs was simulated with the software ANSOFT, and electromagnetic parameters were retried from S parameter. From analytic result and the retrieval result of electromagnetic parameters, left-handed behavior was obvious in a specific frequency range and the permittivity, the permeability and the index of refraction are all negative.
Abstract: We report a peculiar surface of poly(ethylene oxide) (PEO) film from droplet of water-PEO solution dried at heating substrate. The drying process contains two stages. The contact line is pinned initially. When substrate temperature reaches 60 °C, it starts to recede and continues to leave a film. The resulted film contains an edge-ring and middle-step surface profile. The rheological properties of PEO solution were studied. We found that capillary flow is dominant in the first drying stage and Marangoni flow appears because concentration gradient induced strong Marangoni effect and high temperature induced sharply decrease of viscous stress resulted in the contact line receding in the later drying stage. We confirm that the ringlike deposit is formed by outward capillary flow and the step in the middle is formed by Marangoni flow which carries solute to the inner, and these flows compete with the viscous force.