Advanced Materials Research Vols. 79-82

Abstract: With development of traffic speed, friction materials were required more and more high, in this paper polymer matrix friction material reinforced with fibers was studied. The rigid modified phenolic resin and the soft rubber were mixed to form “polymer alloy”, which was the matrix of friction material. When the amount of resin-rubber blending system was 20~25%, the friction material had better friction performance. Carbon fiber had distinct effects on friction performance and mechanical properties. Friction material was a multicomponents composition, so the physical and chemical changes in material were complex. By TEM it was observed that “sea-island” blending system was obtained by mechanical mixing, in which rubber particles formed uniform distribution. By FTIR analysis it was known that because of the force-chemistry of polymer and time-temperature equivalence principle, resin chemically reacted with rubber during the mixing process.

Abstract: Nano size silver films were deposited on the surface of regenerated cellulose films by magnetron sputtering, to impart antibacterial functionality to the cellulose films. Field emission scanning electron microscopy (FESEM) images revealed that the silver films were composed of nano size compact grains and the surface shape of the grains changed with changing sputtering power. As the power increased, the size of the nano silver grains increased and the number of grains decreased. Surface elemental analysis by energy dispersive spectrometry (EDS) showed a small amount of elemental silver on the surface. The antibacterial activity of the films was assessed by the shake flask test which measured the number of Staphylococcus aureus bacteria. The percentage reduction of the bacteria reached >99.9%.

Abstract: The synthesis, morphology, and photophysical properties of poly[2,7-(9,9- dihexylfluorene)]-block-poly(2-vinyl pyridine) (PF-b-P2VP) with different coil lengths in mixed solvents of THF/methanol are reported. A flakes-like lamellar morphology is observed at a short coil length of PF-b-P2VP. As the coil length increases, a spherical and large compound micelle is formed. Upon further increase of the coil length, the morphological transformation from spherical micelles to long rod-like structures is observed. TGA results indicate a good thermal stability of the prepared copolymers. The spectra of optical absorption for the PF-b-P2VP in solution have a blue shift when the fraction of methanol in the mixed solvent increases. The present study shows that the significance of the rod/coil ratio and selective solvent content on the aggregate morphologies and photophysical properties of the rod-coil block copolymers.

Abstract: Taking the waterless tap-hole clay in the 1750m3 blast furnace of Jinan Steel Corporation for example, thermal processing at temperatures ranging from 200°C to 1400°C has been performed. The authors systematically investigated the main features of the clay such as bending strength, compressive strength, porosity and density after thermal processing, the microstructure evolution of the clay with increasing temperature were also studied in brief. Research results provide theoretical information for the practical application of tap-hole clay in the blast furnace and are also helpful for understanding the possible property transition of the tap-hole clay in the tap-hole.

Abstract: In this paper, a novel poly(butyl methacry1ate)/poly(methyl methacrylate-itaconic acid)(PBA/P(MMA-ITA)) latex particles with core/shell structure (CSR) was synthesized by the method of pre-emulsion semi-continuous seeded emulsion polymerization. The core/shell structure of CSR was characterized by TEM and confirmed that the average size of CSR particles was about 330 nm and that of PBA core was about 290 nm. The polyamide 6 (PA 6)/CSR blends (N/CSR) were prepared by the melt-blending technique, and its impact strength reached 40kJ•m-2 (more than 7 times higher than neat PA 6) when the ITA dosage was in the range of 4%~10%. The results of SEM showed that the high toughness of N/CSR blends was the result of the shear deformation of PA 6 matrix induced by cavitation of dispersed phase CSR.

Abstract: Microstructure of 0.63C-12.7Cr martensitic stainless steel during various tempering treatments was investigated in this study. Results demonstrate that finely distributed primary carbides were observed on 0.63C-12.7Cr martensitic stainless steel. The matrix phase of 0.63C-12.7Cr martensitic stainless steel when tempered below 500 °C was identified as martensite. However, the matrix structure when tempered at 500 °C and 600 °C was found containing of both ferrite and martensite. On carbide particles, mixed of M7C3 and M23C6 particles were observed on all specimens when tempered at 200-600 °C. The amount of M7C3 carbides was found decreased as the tempered temperature was increased.

Abstract: Piezoelectric ceramic(lead niobium lithium zirconate titanate, P(LN)ZT), sulphoaluminate cement and polymer were used to fabricate 1-3 polymer/cement based piezoelectric composites by cut-filling technique. The influence of P(LN)ZT aspect ratio on the piezoelectric and dielectric properties of composites was investigated. The results show that as the P(LN)ZT aspect ratio increases, the piezoelectric strain factor d33 and relative dielectric factor εr decrease evidently, while the piezoelectric voltage factor g33 decreases slowly. The acoustic impedance Z is hardly influenced by the aspect ratio. At the same time, the influence of temperature on the dielectric properties of the composites was studied. The results show that with increasing the temperature at the frequency of 1kHz and 150 kHz, the dielectric factor εr exhibits the trend of increase. In the range of -40°C-110°C, the dielectric loss tanδ first increases slowly, but when exceeding the temperature of 80°C, it increases evidently. Comparing with P(LN)ZT piezoelectric ceramic, the vibration at thickness mode of 1-3 type piezoelectric composite is strengthened.

Abstract: The novel visible-light-driven Ag/BiVO4 composite photocatalysts were successfully prepared by photo-deposition method. The as-prepared Ag/BiVO4 samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and UV–vis diffuse reflectance spectra (DRS). The photocatalytic activities of the Ag/BiVO4 powders were determined by degradation of methyl orange molecules in water under visible light irradiation (λ>400nm). The photocatalytic experiments indicated that the composite samples enhanced photo-activity under visible light irradiation.

Abstract: In this study, heat-acupuncture needle was coated with bioceramics by applying a plasma spray coating method to prevent a skin burn in the heat-acupuncture therapy. The effect of coating on the surface roughness of heat-acupuncture needle was investigated and the surface morphology was examined by scanning electron microscope (SEM). The effect of coating on the heat conduction of heat-acupuncture needle was also investigated. The results showed that the surface roughness of uncoated, Al2O3, and ZrO2 coated needle was 0.0675um, 8.568um, and 3.285um, respectively. The surface of ZrO2 coated needle was more uniform than that of Al2O3 coated needle. The results also showed that the heat conduction of heat-acupuncture needle was significantly affected by the bioceramic coating on the needle. Specifically, the maximum temperature of middle part of uncoated, Al2O3, and ZrO2 coated needle was 48°C, 38°C and 42°C, respectively.

Abstract: Flames offer potential for synthesis of carbon nanotubes(CNTs) in large quantities at considerably lower costs than that of other methods currently available. Synthesis CNTs from V-shaped pyrolysis flame is a kind of novel technique. This study aims to examine conditions for CNTs formation in V-shaped pyrolysis flame. Synthesis inner the V-shaped body and providing heat outer is distinct characteristic in the method. A premixed carbon monoxide/hydrogen gas diluted by helium gas flow was introduced into V-shaped body bottom centre. Simultaneously, as catalyst precursor, pentacarbonyl iron was entrained after ultrasonic atomization into the central pipe by helium gas flow. The rich acetylene/air premixed gas, providing heat source, was introduced into V-shaped body outside surface. Scanning electron microscopy and transmission electron microscopy images of the carbon products were examined. Large quantities of CNTs with the less carbon impurities were formed in the process. Carbon nanotubes can grow well when the sampling time was 5 minutes.A nanotube formation ‘window’ is evident with formation limited to fuel equivalence ratios between 1.6 and 1.8. Furthermore, temperature range was from 850°C to 950°C.Nanoparticles associated with nanotube bundles were identified as primarily ferric oxide.