Advanced Materials Research Vols. 560-561

Abstract: At present, tetra-hydroxymethyl phosphonium chloride (THPC) is widely used in flame retardant finishing, industrial water treatment and leather manufacture industry etc., and its decomposition which was caused by pH changing will influence on the actual application. So acid-alkali decomposition of THPC was studied by 31P Nuclear Magnetism Resomance (31P NMR), spectrophotometry and titration respectively. The results show that THPC solution is stable when pH9.0, all of the phosphorus compounds converts to TrHPO. Consequently, THPC content decreases when pH of the THPC solution rising, which could give a favorable guide in THPC application.

Abstract: Lignin-urea-formaldehyde resin adhesive was synthesized with alkali lignin from gramineae waste pulping liquor. Alkali lignin was purified and hydroxymethylated with HCHO and then crosslinked with urea-formaldehyde resin, polyvinyl alcohol and melamine. Results showed that lignin content in purified alkali lignin was 86.91%, both binding strength and free HCHO content of urea-formaldehyde resin synthesized from hydroxymethylated lignin reached the optimum value. The proper lignin amount for preparing resin was 30%, and the binding strength at this condition was 4.56MPa, and free formaldehyde content was 0.049%.

Abstract: A new lightweight thermal insulation board, containing expanded perlite and inorganic silicate binder with corresponding industrial production procedure was developed. The industrial technology was developed in cooperation between company Trimo d.d. and Faculty of chemistry and chemical technology Ljubljana and among others includes mixing of raw materials, molding, microwave drying and high temperature treatment of the dried board. A new product has low density (130 – 160 kg/m³), good mechanical properties and durability and can be used in various fields where inorganic thermal insulation is required. The current work presents the experimental study of the final process during plate production – high temperature treatment with sintering. During thermal treatment of the board, certain shrinkage is required to obtain sufficient mechanical properties and durability. Controlling the process of high temperature thermal treatment is the key to achieve the right balance between low final density of the board and its good mechanical properties.

Abstract: Three-parameter statistical method of the calculation of Qn distribution in silicate melts and glasses has been developed. The method allows determining the concentrations of silicate structural units in wide compositions range at different temperatures when only the limited experimental data are available. The method is based on a destruction of the preassigned network as a model of the interaction of the modifier oxide with a silicon-oxygen framework. Qn distributions in binary alkali silicate glasses and melts were determined by this method. It was found that Qn distribution does not depend on a topology or dimension of the initial network. Moreover, a linear correlations were found to be exist between ln(1/wi) values (w1 and w2 are the first and second adjustment parameters) and 1/rM (rM is cation radius, M = Li, Na, K, Rb, Cs). These correlations allow using the concept of a “fictitious” cation radius in order to calculate of the Qn units at different temperatures.

Abstract: Abstract: The precursor of LiNi0.5Mn1.5O4 cathode material with high density was synthesized by two-dryness co-precipitation method. The feasible parameters were found out by studying the manner of dryness. The highest density (1.74 g/cm3) of precursor can be achieved under two-step dryness. Results of chemical and XPS analysis, XRD and SEM show the ratio of Ni to Mn is 1:3 and the precursor shows slice structure with well crystallization. Test of charge/discharge shows LiNi0.5Mn1.5O4 from such precursor exhibits a good electrochemical activity.

Abstract: The effect of synthesis time on phase compositions, lattice constant and surface morphology of samples synthesized at 1773K were analyzed by XRD and SEM. The results are: the main phase of sample synthesized for 30min is 12CaO•7Al₂O₃, besides it also has little quantity of CaO•Al₂O₃. When prolonging synthesis time the phase tends to be 12CaO•7Al₂O₃ only. The lattice constant increases as synthesis time prolongs. The micro-morphology of samples synthesized for different time changes greatly. There are more and bigger holes in samples synthesized for longer time than that of short time. The comprehensive influences of phase compositions, lattice constant and surface morphology caused the differences of alumina leaching ratio of 12CaO•7Al₂O₃ synthesized for different time.

Abstract: Carbon micro-spheres (CMSs) with diameters of several micrometers were synthesized by surfactant-assisted self-assembly of direct coal liquefaction products, which come from the lignite liquefaction with NaOH and methanol. The synthesized CMSs were characterized by X-ray diffraction, scanning electron microscope and TG analysis. The results show that cetyltrimethylammonium bromide (CTAB) and carbonization temperature play an important role in the formation of CMSs. The CMSs have a spherical morphology, smooth surface, probable size of about 5-10μm and a relatively high thermal resistance in N2 atmosphere. The formation mechanism of these CMSs was discussed based on the feature of the reaction system.

Abstract: An efficient yeast cell biotransformation process was set up for asymmetric synthesis of (R)-(-)-mandelic acid ethyl ester, a key drug intermediate. Saccharomyces cerevisiae 21 was selected as optimum strain for biotransformation. The optimum reduction conditions are as follows: substrate concentration 20 g/L, cell concentration 140 g/L, reaction time 36 h, temperature 30 0C. Conversion and enantiometric excess of (R)-(-)-mandelic acid ethyl ester reached 99.8 % and 100%.

Abstract: This paper suggests the concept of hierarchical control based virtual coordinated synchronization of chemical auto catalytic reaction networks. Under the new framework, the virtual coordinated variable is introduced, which is the average of the ensemble of the corresponding auto catalytic reaction networks, and on account of that, synchronization becomes possible. Unlike the already existing results, the average of the virtual coordinated variable is injected into the every auto catalytic reaction networks. And for the virtual coordinated construction has a lot of flexibility, so the suggested scheme can be easily extended to the multi-purposes control of the auto catalytic reaction networks.

Abstract: The mono-dispersed Co3O4 nano-particles were prepared by means of solid phase synthetical method. The particle size, specific surface area, crystal structure and morphology of the samples were characterized by laser particle size analysis, x-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. The catalytic effects of nano-particles on the combustion of fuel rich propellant were investigated. The results show that the Co3O4 nano-particles prepared are uniform and with relatively wide size distribution curve. The catalytic effect of Co3O4 nano-particles on the fuel rich propellant is stronger than those of micro-sized Co3O4 particles and CuO nano-particles.