Advanced Materials Research Vols. 631-632

Abstract: To solve the problem of sediments on seismic response of concrete dams, pressure wave formula of saturated porous fluid-solid two-phase medium was derived from the Bait’s consolidation theory, and was determined the seismic response magnitude of sediment on concrete dam. The method was applied to analyze the influence of sediments thickness and permeability on hydrodynamic pressures. Finally, a typical example is analyzed. The result shows sediments are able to decrease hydrodynamic pressures.

Abstract: In this paper, a novel grafting poly(butyl methacry1ate)-poly(methyl methacrylate) (PBA/PMMA) latex particles with core-shell structure was successfully synthesized by the method of pre-emulsion semi-continuous seeded emulsion polymerization. PMMA shell layer was cross-linked structure, and it was almost grafted onto PBA core due to the presence of the grafting agent ALMA. The influences of the amount of emulsifier and initiator, and reaction time on PBA core emulsion properties were investigated by analyzing BA conversion and PBA core particles size distribution. The influence of the amount of grafting agent on the polymerization system was also discussed by determining BA conversion and the gel content of PBA core emulsion. PBA/PMMA latex particles were characterized by laser particle size analyzer, transition electron microscopy (TEM).

Abstract: The core-shell structure copolymer of PBA/PS was prepared using pre-emulsion and semi-continues polymerization process. The particle size of core-shell latex and the St conversion of shell monomer were affected by emulsifier, initiator, pH and temperature etc. Meanwhile, the laser particle size analyzer, transmission electron microscope and other test methods were utilized to study latex particle average particle size, size distribution and morphological structure, respectively. The kinetics of polymerization was investigated. Well-defined core-shell structure and narrow particle sizedistribution could be achieved under starved conditions of monomer feeding. By the means of TEM found that PBA/PS latex particles had clearly core/shell morphology.

Abstract: In this article a kindof nanometer silicon dioxide material which prepared by co-precipitation method was used to improve the properties of ordinary raw material of polypropylene packing film. The results show that the nanometer silicon dioxide material not only greatly increased the notched izod impact strength of modified PP but also increased its flexural modulus and flexural strength and when the content of nanometer silicon dioxide material is less than 1%, the HDT of the modified PP is also lightly increased, and the same time other mechanical properties like tensile stress stay as before. Non-isothermal crystallization behavior of modified PP by this nanometer silicon dioxide material was investigated by differential scanning calorimeter. According to the study on the melt rheology,at a low shear rate, apparent viscosities of PP modified by the nanometer silicon dioxide material were lower than that of pure PP, which proves the nano-silicon dioxide materials can improve the processability of PP and will be good for the producing of PP packaging film. SEM and XPS method has carried on the attribute to the size of SiO₂ and its distribution.

Abstract: The slip agents used to reduce coefficient of friction of polypropylene(PP) film, but it migrate brought the issue of food safety, to reduce of the corona effect and the peel strength of flexible film. We try another method to reduce the coefficient of friction. The result shown that the nano-modification not only reduces the coefficient of friction of PP, but also reduces the adsorption of volatile organic solvent in PP. The coefficient of friction of modified polypropylene was reduced by 50% when the concentration of nano-silica is between 1~2%. The final residues toluene in modified polypropylene was reduced to zero when the concentration of nano-silica in PP is between 1~3%. The modified polypropylene agrees quite well with food safety.

Abstract: Polyimide fibers and polyamide acid fibers was used as main materials to produce Polyimide fiber paper. A certain amount of PEO and aramid pulp was added and the sheet was treated by immersion and hot pressing in specified process. The experimental results showed that when the dosage of PEO and aramid pulp were 0.06% and 6% respectively, the sheet tended to present more excellent strength properties and electrical performance compared with sheet using single polyimide fibers as the main fiber materials.

Abstract: Laccase from Rhus vernicifera was applied to catalyze the polymerization of gallic acid (GA) as a way of “in situ” dyeing and finishing for wool, silk, nylon, cotton and viscose fabrics. The laccase-catalyzed polymerization of GA was confirmed by the results of UV-vis spectroscopy and differential thermal analysis. The adsorption of the GA oxidation product on the fibers contributed to the color effect and functional performance of treated fabrics. The dyed fabrics exhibited gray colors with pale to medium shades, depending on fiber categories. All the dyed fabrics showed significantly enhanced UV protection performance and antioxidant activity, and the dyed wool and silk had obviously improved deodorizing ability. These improved functional properties were related to the increased quantity of aromatic rings, phenolic hydroxyl groups and carboxyl groups in the GA oxidation product adsorbed by fibers.

Abstract: The hot rolling, cold rolling and simulative continuous annealing experiments were carried out in the laboratory on the base of new type SFG HSS (super fine grain, high strength steel sheet). The results show that the microstructure which contains a number of cake shaped grain can be refined and homogenized by the feasible annealing holding time. Contrast to the conventional steel, the SFG steel have the characters of super fine grain, high tensile strength, low yield strength/tensile strength rate, good elongation and high r-value high（the plastic strain ratio）．

Abstract: The effects of welding residual stress (WRS) would be harmful to safety and intensity of pressure vessel. X-ray stress analyzer (XRSA) can be used to non-destructively quantitative analyze WRS. In this study, stress changes of constant stress beam in loading process were tested using strain gauge (SG), strain rosette (SR) and XRSA, and their test results were compared to analyze measurement errors of XRSA. It was found that the property of XRSA meets the experimental requirement. The machining stress in surface of welding test plate could be completely removed after 4 min electrolytic polishing under 1 A current and 100% NaCl electrolyte. The WRS of welding test plate was tested by XRSA after machining stress completely removed, and its distribution along vertical welding seam direction corresponded with theory calculation. Furthermore, XRSA as a non-destructive method will be more used to study WRS of pressure vessel, so these results can provide scientific basis for the studying.

Abstract: Diamond cup wheel is one of important tools for machining of ceramic tile. In this paper, ceramic tiles were ground by diamond cup wheels which segments adding nano-scale rare-earth oxide and nano-scale carbide on a special designed test machine. The wear resistance of diamond cup wheels and materials’ removal process of ceramic tiles had been tested, and grinding ratio were calculated and compared. Different grinding ratios can be obtained according to different technological parameters. The segments of adding nano-scale rare-earth oxide and nano-scale carbide were observed from microgram and metallography structural pattern. The results showed that nano-scale rare-earth oxide and nano-scale carbide can fine structure, make grain boundary clear and increase grasping of diamond grits.