Advanced Materials Research Vols. 518-523

Abstract: Firefighting foam is highly effective in suppressing and extinguishing liquid fuel fires. As the concern of its environmental impacts growing, it is necessary to evaluate its biodegradation in the environment. This article briefly introduces the concept, classification, and the main component of firefighting foam. Also the principle, general process, basis mechanism of the biodegradation of firefighting foam are discussed. There is no standard test methods focusing on the biodegradation of firefighting foam, also relative research and reports are less. Limited research data abroad shows that the biodegradability of some foams are very low, and protein based foams may not easier to biodegrade than synthetic based foams.

Abstract: Through inclusion of different polymer chains with different properties into polyurethane matrix, such as poly(ethylene glycol) (PEG), poly(ε-caprolactone) (PCL), poly(lactic acid) (PLA), or poly(tetramethylene oxide) (PTMG), degradable polyurethane foams (PUFs) with different molecular structure were prepared. Influences of molecular structure on PUF materials’ performance were studied systematically. When PEG, PCL, PLA, and PTMG serve as soft segment, PUFs’ storage modulus and glass transition temperature (Tg) of PUFs decrease with following order: PLA>PCL>PEG>PTMG (flexibility of PUFs varies oppositely). And degradability decreases according to following order: PEG>PLA>PCL>PTMG. With increasing content of PEG or PLA chains in PU matrix, mechanical performance of PUFs decrease gradually, but remains on the same order with conventional non-degradable PUFs. Through control on the contents of different kinds of polymer chains in soft segments of PUFs, fairly good degradability can be achieved, at whilst their basic mechanical performance is well guaranteed.

Abstract: The formula of the environmental protection PVC sheathing compound used for wires and cables contains: the base resin, composite stabilizer, plasticizer, filler, antioxidant and lubricant. In this paper, each component’s effects on the performance of the sheathing compound were studied. The optimized formula was established as: 100.00 phr PVC SG-3, 7.80 phr Ca/Zn stabilizer, 38.00 phr DIDP, 11.00phr DOTP, 34.50 phr ground calcium carbonate, 0.40 phr Bisphenol A, 0.70 phr lubricants, and 1.50phr coloring agent. The product properties were tested. The results indicate that this formula system contain neither heavy metals such as lead, cadmium, hexavalent chromium and mercury, nor polybrominated biphenyls and their ethers, which can cause significant damage to people and the environment. The product property completely meets the performance standards set for the environmental protection 90 °C PVC sheathing compound.

Abstract: Ag, Pd loaded Bi2WO6 photocatalyst were prepared via a photoreduction process and characterized with UV-Vis-DRS, XRD and FE-SEM. The photocatalysis experimental results indicated that the photocatalytic activity of Ag-loaded Bi2WO6 was greatly enhanced compared with pure Bi2WO6, and the content of silver has an impact on the catalytic activity of Ag-loaded Bi2WO6 photocatalyst. The loaded Ag and Pd acts as the electron receptor on the surface of Bi2WO6, which inhibits the recombination of photogenerated charge carrier between Ecb to the Evb in the Ag-loaded Bi2WO6. As a result, the reduction of electron-hole recombination decreased, which could significantly improve the photocatalytic activity.

Abstract: Recently, Graphene oxide (GO) has attracted enormous interests due to its extraordinary properties. GO sheets are expected to find a variety of applications, such as GO-based composites materials and biotechnology. The nanocomposites of Poly (ε-caprolactone) (PCL) and graphene oxide (GO) were successfully synthesized by in-situ polymerization. WAXD indicated that the PCL/GO composites formed an exfoliated structure. And Polarized Optical Image (POM) showed that the graphene oxide could be homogeneously dispersed in matrix. What’s more, we also studied the crystallization behavior of the pure PCL and PCL/GO nanocomposites as well as the effects of graphene oxide as the nucleation agent.

Abstract: The way of the friction spun core yarn as the fabric preform used in thermoplastic matrix composites is considered outstanding. The hot processing conditions of forming composites such as the molding temperature, the holding time and the pressure influence the impregnating degree of the composites, which is investigated though the observation of cross-section and tensile strength.

Abstract: This paper introduced a kind of oil absorption polyurethane foam (PUF) material, which had good absorption on a variety of liquid hazardous chemicals. The absorption rate of this material while absorbing crude oil can reach 40g / g or more and the absorption rate to xylene is 49.9g / g. In addition, this paper also discussed the relationship among the cell opening rate, volume availability and the oil absorption rate of the foam material, comparing with oil absorption felt, the commonly used absorption materials. Researchers observed the microstructure of PUF by the scanning electron microscope, discussed its oil absorption mechanism and analyzed its emergency disposal in the leakage accident of hazardous chemicals.

Abstract: This paper reports the adsorption of Cr(VI) ions from aqueous solution by organic-inorganic hybrid mesoporous material. Adsorbents were prepared with the DTAB,TTAB,CTAB and STAB for organic component synthesis organic-inorganic hybrid mesoporous material(HM), namely HMD, HMT, HMC and HMS. The best adsorption hexavalent chromium experimental conditions is obtained after having orthogonal experiment.

Abstract: Europium doped tantalum oxide (europium-Ta₂O₅) particles were synthesized with a low temperature hydrothermal method. The electrochemical behaviour of an europium-Ta2O5 film electrode in 0.1 mol dm^-3 KCl solution containing 5 mmol dm^-3 K₃Fe(CN)₆ was investigated using cyclic voltgrammetry (CV). The CV results indicated that the europium-Ta₂O₅ film electrode exhibited good stable and reversible electrochemistry properties. The electrochemical reaction of K₃Fe(CN)₆ was a diffusion-controlling process on the europium-Ta₂O₅ film electrode. The europium-Ta₂O₅ particles might have potential applications in electrochemical fields.

Abstract: Photocatalysts TiO₂ and Ag-TiO₂ supported on glass fiber were prepared by sol-gel method. Glass fibers were used not only as a substrate for TiO₂ coating to increase surface area of TiO₂ but also as an adsorbent for bacteria removal by photocatalytic reaction. The surface topography, and optical properties of materials were characterized by scanning electron microscope , and ultraviolet-visible spectroscopy. The prepared photocatalysts were applied to investigate disinfection effects of Escherichia coli (E. coli) in nursing facilities. Ag-TiO₂/glass fiber exhibits much higher photocatalytic activity for disinfection of E. coli under visible light. This increased photocatalytic activity is probably due to the Ag loading effect by narrowing the band gap of the photocatalyst and preventing the fast recombination of the photogenerated charge carriers.