Applied Mechanics and Materials Vols. 423-426

Abstract: The composition of basic magnesium carbonate varies, mainly due to the decomposition conditions of magnesium bicarbonate. In the present study, we researched the specific composition of samples prepared at different decomposition temperatures of magnesium bicarbonate. Combining XRD, TG-DSC and wet chemical analysis, we found that single component which the formula is MgCO₃3H₂O can be got at room temperature (30 °C). Content of MgCO₃3H₂O in the decomposition products decreases with the increase of decomposition temperature. The decomposition products obtained at 90 °C is 4MgCO₃Mg (OH)₂4H₂O based and contain a little MgO, Mg (OH)₂, trace amount MgCO₃3H₂O and 4MgCO₃Mg (OH)₂5H₂O. Further study show that content of MgCO₃3H₂O influences the density of final product of magnesium oxide. Density of magnesium oxide got by calcining MgCO₃3H₂O is 0.944 g.ml^-1, and density of magnesium oxide got by calcining product that was prepared at 90°C is 0.078 g.ml^-1.

Abstract: The phases of high titanium slag were studied by using XRD and XRF. XRF results show that high titanium slag mainly contains the elements, Ti, Fe, Si, Mn, Al, Ca, P, Zr, Mg, Ba, S, K and etc. XRD results show that the main phases of original high titanium slag are some complex solid solutions, such as (Fe0.33Ti0.46Mg0.21)(Ti1.9Mg0.1)O5, Fe2TiO5, Fe3Ti3O10 and etc, and it also contains a spot of rutile (TiO2). After heat treatment for 10h at 1073K in atmospheric ambient, the main phases have been mostly changed to rutile, with an obviously weight gain about 2.9%. It may be caused by the reaction of high titanium slag with oxygen during heat treatment, and that may be conducive to better quality of the high titanium slag and titanium dioxide.

Abstract: Novel polymers with imide and ether were synthesized by pyromellitic dianhydride and Pyromellitic dianhydride (PMDA), 4,4'-metylenedianiline (MDA), amino-teminated polyoxypropylene (D2000). The structures and thermostability of polymer were characterized through FT-IR spectra, thermogravimetric analysis (TGA) and differental scanning calorimetry (DSC), solubility behavior was determined via seven solvents. The results indicate that these polymers have good chemical resistance and exhibit excellent thermostability owing to the introduction of imide units.

Abstract: A new compound was successfully synthesized as an additive in electrolyte used for high-voltage lithium-ion batteries, owing to its unique structure with the sulfone group that can increase conductivity and broaden the electrochemical window of existing electrolyte. Its lowest unoccupied molecular orbital (LUMO) is-2.686 eV, respectively. The lower LUMO value results in formation of solid electrolyte interface (SEI) film on anode surface which is prior to other solvents and can impede the electrolyte composition. Through the electrochemical test, the electrolyte having this additive (0.2 wt%) showed wider voltage window, enduring the potential up to 5.5V higher than that of 4.8V performed by available commercial high-voltage electrolytes. The additive to electrolyte was effective not only for Li/Li₃V₂(PO₄)₃ cell but also for Li/LiMn₂O₄ cells with a cut-off range of 3.0-4.8 V.

Abstract: Phthalazinone structure contained phthalaazione ether sulfone ketone (PPESK) is a kind of excellent engineering plastic with high temperature resistance and resolvability. In this paper, SC-CO₂ was used as foaming agent to prepare PPESK foams by temperature rising method. The influence of technological conditions like foaming time, foaming temperature and saturation pressure on cell density and cell morphology was discussed and analyzed.

Abstract: Barite, as a significant nonmetallic mineral can be widely applied to the fields such as coating, rubber, medicine and other high-tech industrials. While the physical and chemical purification is to remove the impurity elements, so as to confirm to the criteria of relevant industry. The text also summaries the methods of activation and proposes some new applications of barite.

Abstract: The existing alkaline batteries which businesses are unwilling to recycle can only be discarded after used, resulting in a lot of environmental problems. The crust of batteries is made of special steel which can be used repeatedly costing the 1/3 total costs. Batteries are divided into three parts: steel, core, and bottom closures. Thread at the bottom of steel corresponds with the screw thread at the bottom of the closures. As long as screw off closures, load the core, the battery can be used again. The whole process is simple. Creative design has advantages on the structure and energy, environment and energy, economic and cost, greatly improving the recovery efficiency, reducing the cost of recycling and environmental pollution, and has huge economic, social, environmental benefits.

Abstract: This paper presents foaming behaviors of PPEK blown with supercritical CO₂. The cell density and cell size of PPEK at various process conditions were studied. The experimental results indicate that saturate pressure, foaming temperature and suitable foaming time can provide a positive impact on improving the cell morphology of PPEK foams.

Abstract: Phloroglucinol-resorcinol-formaldehyde organic aerogels (PRF) were prepared using phloroglucinol, resorcinol and formaldehyde in a sol-gel process, solvent replacement and drying at room temperature. The phloroglucinol-resorcinol-formaldehyde carbon aerogels (CPRF) were prepared by charring the PRF at high temperature under the aegis of helium flow. The microstructure of CPRF was characterized by infrared spectroscopy, specific surface area analyzer and scanning electron microscopy. The results showed that the CPRF had continuous network structure and high specific surface area.

Abstract: Polymerization of high molecular weight PMMA was achieved in [BMIM]PF₄ at reaction temperature 60 ^o C, 65°C and 70 °C, reaction time 60min. The data including the yield, molecular weight and molecular weight distribution of PMMA were analysized. The results showed that the weight average molecular weight of PMMA in [BMIM]PF₄ is up to 275867, respectively 4 and 7 times of molecular weight in cyclohexane and toluene. Secondly, the polymerization kinetics of PMMA in [BMIM]PF₄ were tested, the apparent chain propagation rate constant of PMMA are 0.93×10⁴,1.11 ×10⁴ and 14.1×10⁴ in 60 °C, 65°C and 70 °C. Compared with the growth rate constant in toluene, the polymerization rate constant PMMA in the ionic liquid increased by 4~7 times.