Advanced Materials Research Vol. 1096

Abstract: Effect of different curing conditions on the mechanical properties of magnesium phosphate cement (MPC), and the water resistance of MPC was improved by adding slag, the influence of slag on component and microstructure of the hydrated product were studied in this paper. The additive amount of slag was 0% ,10% , 20%, 30% and 40% separately in the ratio of total amount of MPC. It indicates that the compressive strength and flexural strength increase by about 30%,40% when the amount of slag reaches 10% of phosphate cement, respectively , and the dissolution of some phosphate which has not reacted can be prevented when cured in water for days, it improves the pH value of the solution, so the main hydration product-MgKPO₄·6H₂O hard to be dissolved under alkaline environment resulting in the decreasing of porosity ,and the decrease of strength would be controlled.

Abstract: The pyridine-containing diacylhydrazones derivatives are functional organic light emitting molecular materials. In this paper, The S₀ ground states and the S₁ excited states of the four pyridine-containing diacylhydrazones compounds were optimized with density functional theory (DFT) at B3LYP/3-21+G level and single-excitation configuration interaction at CIS/3-21+G method, respectively. We discussed in detail the relationships between the molecular orbital energy, absorption and emission performances and the structures of the four compounds. In addition, the analysis on frontier molecular orbital (FMO) energy gaps indicated that the stronger the conjugations are, the much more red-shift of the absorption spectrum will be. According to the calculated absorption and emission spectra data, it can be conclude that four pyridine-containing diacylhydrazones compounds are one of the alternative electron transporting and photoactive materials.

Abstract: Polyimide membrane pervaporation was introduced to separate the costly diene mixtures of cyclopentadiene/methylcyclopentadiene (CPD/MCPD) from cracking C5 fractions. Four kinds of membrane solutions were prepared and two kinds of polyimide homogenous membranes were fabricated by thermal imidizations using the dianhydrides (BPADAand PMDA) and the diamines (ODA and DDS). The effect of the casting solutions viscosity on the membrane formation was revealed, and the formation of functional groups and the synthesis mechanisms of the thermal imidizations were indicated by FT-IR. The adsorption behaviors and the pervaporation performances were studies for BPADA-ODA and PMDA-ODA membranes. The results show that the permeation fluxes are 164g∙m^-2∙h^-1 and 4.2g∙m^-2∙h^-1 for BPADA-ODA and PMDA-ODA membranes respectively, while the separation factor are 1.93 and 8.9 for these two membranes respectively. 88.5 wt% concentration of MCPD was achieved in the circulated feed side ultimately.

Abstract: A novel recovery process of the effective ingredient from the waste metal cutting fluid was proposed by the combination of solvent extraction and solid adsorption technique. The influence factors such as the volume fraction of 1-butanol, the ratio of solvent to oil, the quantities of KOH and the extraction temperature were studied through experiments. The results show that: The maximum quality of oil sludge was obtained when added 3g KOH to waste liquid(200ml).The mass of oil sludge was found to increase with the increase of solvent to oil ratio until it reached the maximum at the ratio of 3:1.

Abstract: Organic CHNO-containing high energy density materials have been widely used for storing large amounts of the chemical energies which can be rapidly transformed into heat upon various external perturbations during detonation. The sensitivity of the energetic materials is subjected to considerable concern for safety and maintenance. Periodic density functional theory with the all-electron basis sets were employed in this work to unravel the impact, friction, and electric-fields induced decomposition of HMX. The minimum energy paths for the N−NO₂ homolysis reactions of HMX in the bulk and gas phases were obtained. The surface-enhanced effect on the decomposition of HMX were calculated for both (010) and (100) surfaces. A general theoretical scheme has been proposed to assess the intrinsic mechanic and electrostatic sensitivities of the pure energetic materials.

Abstract: Tencel fabrics were treated with low pressure plasma with air for different treatment time. The samples were tested their thickness and calculated each mean value of fabrics treated with different time. The result indicated that samples became thicker with the prolonged plasma treatment time. The samples were also divided into two groups and tore along warp and weft direction, respectively, to measure the influence of plasma treatment time on the tearing strength. The result of the measurement implied that the tearing strength of samples treated 1 minute by plasma decreased dramatically, when they were compared with the untreated ones. However, the decrease of the tearing strength became slight when the plasma treatment increased to 5, 10 and 20 minutes.

Abstract: By the use of finite element method, this paper predicts the effects of the shapes of reinforcements with different ductility (Co) on the effective elastic response for WC-Co cemented carbide. This paper conducts a comparative study on the material properties obtained through theoretical model, numerical simulation and experimental observations. Simulation results indicate that the finite element method is more sophisticated than the theoretical prediction.

Abstract: MnO_x/ luffa sponge composites were prepared by loading MnO_x on/in porous luffa sponge under ambient conditions and an in-situ reduction method. We employed the oxidative decomposition of HCHO as probe reaction to investigate the effect of KMnO₄ concentration on the catalytic activity of MnO_x/ luffa sponge composites. It is shown that all the MnO_x/ luffa sponge composites bear the activity for the catalytic decomposition of HCHO; the conversion of HCHO was found to be high at room temperature; the conversion level of HCHO was first increased and then decreased with the increase in the KMnO₄ concentration. The HCHO conversion over the catalyst prepared from 10 g/L of KMnO₄ solution was the largest among five catalysts.

Abstract: Flame retardation of banana fiber reinforced epoxy composites using melamine pyrophosphate and pentaerythritol as intumescent flame retardants and the influence of mechanical properties were investigated. The effects of IFR contents and the ratio of MPP and PER on limiting oxygen index (LOI) and UL94 rating of banana fiber reinforced epoxy composites has been studied. It was found that the combustion performance of the composites increases with increasing IFR contents,and the composites at the ratio of MPP/PER=2:1(weight ratio) at the same loading 40% showed the best combustion performance with IFR contents increasing,the limiting oxygen index (LOI) increased and UL94 rating reached, but the mechanical properties of composites significantly decreased. In order to increase the comprehensive properties, the flame retarded fiber was used to prepared the composites,the limiting oxygen index (LOI) of the composites significantly increased. the best complex properties were the IFR contents was 40%, the ratio of MPP/PER=2:1 (weight ratio), by the spraying method with 20g the fire retardant liquid of every 30g banana fiber.

Abstract: The LiCl/DMAc was used as solvent system to dissolve meta-aramid short fiber, the aramid fibrid was prepared by injecting the aramid solution into the high shearing coagulant at room temperature and the mixture of water and N, N-dimethylacetamide (DMAc) was used as coagulant. The aramid fibrid and aramid short fiber were mixed at differents weight proportion, wet paper was dried and aramid paper was prepared by heat pressing. The aramid paper has excellent mechanical properties when the weight proportion of the aramid fibrid and aramid short fiber was 60:40,and it had a good thermal bonding between the fibrid and fiber under heat pressing. The hydrophobic SiO₂ was mixed with aramid fibrid and aramid short fiber (60:40) in ethanol, and aramid/aerogel composite was prepared by drying and hot compressing. The composite had a good heat-resisting, however, the mechanical property decreased with the content of aerogel increasing.