Advanced Materials Research Vols. 391-392

Abstract: The manufacturing cost of asphalt flame retardant is very expensive since it mostly comprises halogen, stibonium and boron composite system. As a result, its use is restricted. In this paper, three kinds of cheap phosphorus, nitrogen flame retardants and two kinds of inorganic flame retardants for modifying asphalt. Based on limit oxygen index, the effect of one-component and multicomponent flame retardant on asphalt flame-retardant performance was analyzed. Moreover, in phosphorus-nitrogen-aluminum and phosphorus-phosphorus-aluminum flame-retardant experiments, it was found that phosphorus-aluminum composite system also has good flame-retardant effects, and the optimal proportion was obtained. The experiments validated that its flame-retardant performance can reach difficult flammable level-2 standard, fully satisfying the use need of tunnel surface, and substantially reducing the technical-economic cost of flame-retardant asphalt. FRC index proposed in this paper takes into full consideration the flame-retardant performance and economic cost for modification of asphalt, and provides important reference to the selection of master plan.

Abstract: Calcium silicate (CS), the recent developed biodegradable ceramic, shows potential in stimulating bone regeneration. However, the rapid degradation restricts its further application, that is, the cytotoxicity is highly suspicious. In this study, the attempt with the addition of strontium by partially replacing the site of calcium shows appropriate, not only enhancing the bioactivity of CS, but also promoting its biocompatibility. Thus, the modification of biomaterial by strontium seems to be an effective approach for biological application.

Abstract: The intumescent flame retardant poly-pentaerythritol diphosphonate dichloride- hexamethylendiamine (PSPHD) grafting sepiolite (PSPHD-SEP) and LDPE/PSPHD-SEP/IFR composites have been prepared. Cone calorimeter technique was employed to characterize the combustion behavior of LDPE/PSPHD-SEP/IFR composites. The results show that the peak and average heat release rates decreased significantly when 5% PSPHD-SEP was added in LDPE. The PSPHD-SEP can promote the char layer to form earlier and be more compact and increase the char residue yield. The compact char residue layer can prohibit the transfer of gas and heat during the burning, showing the improvement of flame retardance.

Abstract: A novel intumescent flame retardant oligomer containing phosphorous-nitrogen structure (PSPTR) was synthesized and characterized by Fourier Transform Infrared (FTIR) and Mass Spectrometry (MS). The thermal behavior of PSPTR was investigated by thermogravimetric analysis (TGA). The TGA data shows that PSPTR has a high initial temperature of thermal degradation and a high char residue of 41.18wt% at 700 . A novel intumescent flame retardant (IFR) system, which is composed of PSPTR and novolac phenol (NP), was used to impart flame retardancy of ABS. The combustion behaviors of the ABS/IFR composites were investigated by Limiting Oxygen Index (LOI) and UL-94 tests. When the content of IFR (PSPTR:NP=1:1 mass ratio) is 30 wt%, the LOI value of ABS/IFR reaches 28.2, and the vertical burning test reaches UL-94 V-1 rating.

Abstract: In this study, a high thermal conductivity novolac resin /graphite nanosheet composite have been prepared via in situ polymerization at the presence of sonicated expanded graphite. Graphite nanosheets prepared via powering the expanded graphite had a thickness ranging 10~100 nm and a diameter range 5~10μm and were excellent nanofiller for the fabrication of polymer/graphite nanocomposite. Scanning election microscopy was used to characterize the structure and dispersion of the graphite nanosheets and the composites. The results showed that the structure of the nanosheets played an important role in forming thermal conducting network in the novolac resin matrix.

Abstract: The thermomechanical control processing (TMCP) was conducted through the adjustment of the rolling technological parameters to the test steel. The influence of the finishing temperature, cooling rate and alloying elements to the microstructure and mechanical properties was investigated by comprehensive utilization of grain refining strengthening and second phase strengthening.The results show that the microstructure was mainly composed of bainite, ferrite and second phase TiC; at the finishing temperature of 870°C, the yield strength was 596.7 MPa, the tensile strength reached 748.5 MPa, the elongation ratio was 20.17%; at high cooling rate of 16°C/s, the yield strength achieved 616.7 MPa, the tensile strength reached 785.5 MPa, the tensile ratio reduced for 0.78, and the elongation ratio enhanced to 20.92%. And the quantity of bainite increased with the raise of finishing temperature from 800°C to 870°C, which improved the hardness and wear resistance of the steel.

Abstract: Nanocrystals with different Eu3+ doping levels (%) were prepared by sol-gel and hydrothermal synthetic method using titanium tetraisopropoxide (TTIP) as titanium source. The products exhibited anatase phase structure, mesoporosity, and interesting surface compositions with three oxygen species and two titanium species. The crystallite sizes, crystal form, surface shape, composition and optical property of catalysts were characterized by X-ray diffraction patterns, UV-Vis diffuse reflectance spectroscopy, XPS and inductively coupled plasma atomic emission spectroscopy. The products were used as the photocatalysts to degrade a partially hydrolysis polyacrylamide (HPAM) under UV-light irradiation, a very useful polymer in oil recovery. For comparison, Degussa P25 and as-prepared pure TiO2 were also tested under the same conditions. The enhanced photocatalytic activity was obtained on as-prepared Eu3+ composites, and the reasons were explained.

Abstract: Spindle-like bis (8-hydroxyquinoline) iron (FeQ₃) complex has been synthesized with a facile method in a mixed solvent system at room temperature for 12 h. The molecular formula of the products is speculated by the C, H and N element analysis and thermal gravimetric analysis, and Fourier-transformation infrared spectroscopy was also utilized to measure its structure, which further confirm the molecular formula of the products. The observation of field emission scanning electron microscopy and transmission electron microscopy shows that the morphology of tris (8-hydroxyquinoline) iron complex is spindle-like structure. The photoluminescence of the products were also investigated. The results indicate that the photoluminescence emission of FeQ₃ spindles shows obvious blue shift contrasted with that of 8-hydroxyquinoline.

Abstract: Based on using combustion synthesis under high gravity to prepare TiC-TiB₂ composite, the ceramic armour targets were achieved by the heat-shrunk laternal, cover and back confinements of steel sleeves and plates. Ballistic testing showed that under the impact of long-rod tungsten alloy projectile, the low-carbon-steel sleeve failed to laterally confine the ceramic due to its inadequate residual strength, resulting in poor ballistic performance of the ceramic, whereas the medium-carbon-steel sleeve had a sufficient residual strength to support lateral confinement of the ceramic as the long-rod tungsten alloy projectile makes room in the ceramic for its penetration, the confined ceramic could present its real ballistic performance, and the results of ballistic testing promised lateral confinement and cover confinement of high-strength metal would be beneficial to the improvement in ballistic performance of ceramic armour.

Abstract: Based on preparing TiC-40mol%TiB₂ composite by combustion synthesis under high gravity, the ballistic targets with different-thickness ceramic tiles were achieved by lateral, cover and back confinements of shrink-fit steel. Ballistic testing showed that as the thickness of ceramic tile was smaller than 12 mm, the penetration of the ceramic tile was mainly controlled by the combination of the initial-shock and steady-state penetration, resulting in poor ballistic performance of the ceramic. As the thickness of ceramic tile was larger than 12 mm, the penetration of the ceramic tile was controlled by the combination of steady-state and third-stage (projectile deceleration and erosion acceleration) penetration, resulting in improved ballistic performance of the ceramic.