Materials Science Forum Vols. 610-613 | p. 2

Using Demercurated Lighting Phosphor and MSWI Scrubber Residues to Prepare High Performance Plastic Concrete

Authors: Wu Jang Huang, Wei Chu, Ling Hui Hsieh, Jian Guo Chen

Abstract: This study aimed to prepare a high performance plastic concrete made of epoxy resin and Portland type-I cement mixed with at least one inorganic solid waste of demercurated lighting phosphor powder or municipal solid waste incineration scrubber residue. The ratio between liquid epoxy resin and cement was 1:2; the scrubber residue and demercurated phosphor powder were added as modifiers for cement component in order to improve the strength and thermal properties of synthesized plastic concrete. The results indicate that, the addition of scrubber residue causes a decrease in both strength and thermal properties; whereas, the demercurated phosphor powder can replace 100% of the contents of cement without any significantly change in either strength or thermal properties. Atomic force microscopy and Raman spectroscopy were used to characterize the chemical structure of cured concrete and the results indicate that the surface softness increases with an increase in the mixed percentage of epoxy resin.

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Directly Synthesis of Polymeric Nano-Composite from Waste Solid Absorbents of Treating Styrene Monomer-Containing Waste Gas

Authors: Wu Jang Huang, Ling Yin Chang, Hsiu Hsien Wu, Yan Jia Liou

Abstract: This study aimed to synthesize polystyrene (PS)-TiO2 nano-composite from the waste solid absorbent directly, so that the waste TiO2/PS solid absorbent could be used as nano-materials. TiO2 powder with a particle size of 12 nm was used for the solid absorbent. The TiO2 packed scrubbing tube was used for treating synthetic waste gas that contained styrene monomer. Experimental results confirmed that the concentrations of styrene in synthetic waste gas can be reduced by 62% after the activation of photocatalyst, and the lifetime of activated TiO2 catalyst is over 2 hours. From the NMR and DSC spectra of obtained products, PS is actually grafted on the surface of TiO2. The glass transition temperature of obtained PS in TiO2/PS solid absorbent is 100oC.

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Fast Removal of Pb²⁺ from Aqueous Solution by Water Insoluble Konjac Glucomannan

Authors: Xue Gang Luo, Feng Liu, Xiao Yan Lin

Abstract: Konjac glucomannan (KGM) was converted into water insoluble konjac glucomannan (WIKGM) by treating with NaOH through completely deacetylated reaction. Adsorption study was carried out for the adsorption of Pb2+ from aqueous solution using water insoluble konjac glucomannan. The influences of pH, contact time, temperature and initial Pb2+ concentration on the absorbent were studied. Results of kinetic data showed that the Pb2+ adsorption rate was fast and good correlation coefficients were obtained for the pseudo second-order kinetic model. The equilibrium process was described well by the Langmuir isotherm model with maximum adsorption capacity of 9.18 mg/g on WIKGM at 25°C.

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Experimental Study of the Mechanical Properties of Hybrid Fiber Reinforced Concrete

Authors: Yuan Hua, Tai Quan Zhou

Abstract: Different kinds of fiber are used to reinforce the concrete to improve the concrete mechanical properties. The high modulus and high flexibility fibers are often used to reinforce in the cement base, which leads to the higher performance compound cement based materials. In the paper, the carbon fiber and glass fiber material are used as flexibility reinforced materials. The polypropylene fiber and the polyethylene fiber are used as strength reinforced materials. The combinations of the flexibility reinforced fiber and strength reinforced fiber are chosen as C-P HF (Carbon and Polypropylene Hybrid Fiber) and G-Pe HF (Glass and Polyethylene Hybrid Fiber). The concrete mixture ratio and the fiber-reinforced amount are determined to the author’s previous study. The relationship between compressive strength, flexural strength and length/diameter aspect ratio of fiber for the carbon and polypropylene hybrid fiber reinforced concrete (C-P HFRC), and for the glass and polyethylene hybrid fiber reinforced concrete (G--Pe HFRC) was tested and discussed. The testing results show that length/diameter aspect ratio of fiber obviously affects the flexural strength of C-P HFRC and G-Pe HFRC, though the compressive strength is slightly affected by the length-diameter aspect ratio.

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Application Study of Polypropylene Fiber Reinforced Concrete Railway Tunnel Lining Structure within Hard Rock Mass Using Wet-Sprayed Technique

Authors: Tai Quan Zhou, Yuan Hua

Abstract: The wet sprayed concrete technique has good virtue of improving the working condition within the tunnel, fewer reflective concrete loss and higher sprayed concrete quality. The concrete mixed with polypropylene fiber could improve the concrete inner structure, the flexural strength, tensile strength and anti-penetrating ability. The application of the wet sprayed polypropylene fiber reinforced concrete in the construction of tunnel lining structure could improve the stability of tunnel rock mass. The nonlinear finite element analysis is performed on rock mass stability of the railway tunnel lining structure and the rock mass stability is analyzed both for the un-lining tunnel and the lining tunnel. The computation result shows that the rock mass plasticity zone distribution with the lining structure is fewer than that without lining structure. To measure the deformation behavior, tunnel deformation measurement sensors are installed in the railway tunnel transverse section. The measured railway tunnel deformation result also shows that the lining structure deforms little and the rockmass is in stable state.

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Study on the Moisture Absorption Properties of Poly[acrylate-co-methacrylate]

Authors: Chun Xiao Zhang, Fu Chen Bai, Xi Yao Zhang, Jian Liu, Wan Xi Zhang

Abstract: Moisture-absorbent poly- (acrylate-co-methacrylate) was synthesized by solution polymerization, using N,N’-methylene bisacrylamide as the crossinglinking agent, sodium bisulfate and ammonium persulfate as the initiator. The moisture absorption properties of the copolymer in different temperatures and humidities have been systematically studied. Experimental results indicated that the moisture absorption behavior has been enhanced with the increase amount of methacrylate. Under different relative humidity, the moisture adsorption ability was distinct. When the relative moisture reached 40%, the humidity behavior became less evident. As the increase of moisture, the absorbency for moisture improves correspondingly. When the relative moisture get to 90%, the properties of this copolymer was obviously improved compared with the traditional materials, such as silica gel and molecular sieve.

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Modelling Flue Gas Desulfurization Using Pyrolusite Pulp in a Jet Bubbling Reactor

Authors: Jing Dong Zhao, Shi Jun Su, Nan Shan Ai, Xiao Fan Zhu

Abstract: A mathematical model for flue gas desulfurization using pyrolusite pulp in jet bubbling reactor (JBR) was described. Firstly, based on the concept of two stages mass balance with chemical reaction, two models were set up, for jet bubbling zone and rising bubble zone, respectively, according to the construction of JBR. The models consist of two coupling differential equations and were solved simultaneously by integral and separation of the variables. Then the SO2 absorption efficiency expression was developed, considering the great discrepancy existing between the gas-side mass transfer coefficients of the jet bubbling zone and gas bubble rising zone. The final expression associates SO2 absorption efficiency with process conditions and JBR structure parameters, which can give some instruction and guidance for the study of reactor operation process. Predicted results from the theoretical model, including effect of pH value of the pulp, flue gas temperature and inlet SO2 concentration of flue gas on SO2 absorption efficiency, were found to be in good agreement with experimental data obtained in a jet bubbling reactor. The model provides a basis for the process scale up and operating guide.

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Enhancement Corrosion Resistance of Two (Vinyl)Silsesquioxane Hybrid Films and their Validation by Gas-Molecule Diffusion Coefficients Using Molecular Dynamics Simulation

Authors: Di Wang, Xiao Dong Chen, Yu Liu, Li Jiang Hu

Abstract: Based on silsesquioxanes (SSO) derived from hydrolytic condensation of (vinyl)trimethoxysilane (VMS) and tetraethoxysilane (TEOS), two hybrid films, f-VMS-SSO (f-VS) and f-VMS-TEOS-SSO (f-VTS) modified with 15 wt-% TEOS, were prepared. The anticorrosion properties (corrosion potential, Ecorr, and corrosion current density, Icorr) of the bare aluminum alloy (AA) and the two films on AA were tested by electrochemical measurements with typical potentiodynamic polarization curves. The Icorr values of three samples are significantly different in the order of f-VTS

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Silsesquioxane Materials as Sun Protection Factor Ingredients and as Films for Greenhouse Covers

Authors: Ping Chen, Tao Liu, Di Wang, Yu Liu, Li Jiang Hu

Abstract: Using polyhedral oligomeric silsesquioxanes (POSS) derived from the hydrolytic condensation of (3–methacryloxypropyl)trimethoxysilane (MPMS), vinyltrimethoxysilane (VMS), and (3-glycidoxypropyl)trimethoxysilane (GPMS), three hybrid nanofilms, f-MP (film-MPMS-POSS), f-GP and f-VP, were prepared using sol-gel and crosslinking processes. The average transparency (AT) and absorption coefficents (AC) of the films were measured in the ranges of 280-2500 nm. Two film transparency applications are described in this work: 1) The AT values of the POSS films in the range of the ultraviolet B (UV-B) spectrum (280–320 nm) (a skin cancer-causing agent) and 2) the AT values in the visible light (VIS) region (400-750 nm) and the near infrared (NIR) region (750-2500 nm) (providing crops growth energy and the improvement of the photosynthetic process efficiency). The AT values of the POSS films in the UV-B range are only about 13%, indicating these films can provide a physical barrier to block UV-B absorption by the skin, and therefore are possible POSS materials for sunscreen ingredients. The AT values in the VIS region are 95.13%, 89.16% and 91.60%, respectively, and the AT values in the near infrared (NIR) region (750-2500 nm) are 95.39%, 93.11% and 90.50%, respectively. These high AT films are good candidates for greenhouse covers. The AT values among the three films in the 280-2500nm region are different and exhibit varied selectivity for absorbed spectra due to the dissimilar sizes of organic branches covalently bonded to the silica network in the film structure.

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Influence of Pore Size on Enzymes Adsorption in Mesostructure Cellular Foams (MCFs)

Authors: Wei Na, Qi Wei, Ze Chang Zou, Zhi Hong Wang, Qun Yan Li, Zuo-Ren Nie

Abstract: Mesoporous silica materials are attractive candidates for enzymes immobilization due to their high surface area, tunable pore size, large pore volume and biocompatibility. In this work, two different enzymes, papain, a small globular enzyme with molecular diameter of 3.6nm, and catalase, a relatively larger enzyme with molecular diameter of 10.4nm were introduced into the pores of siliceous mesostructed cellular foams (MCFs) that had a large cellular pores of 29nm and a small window size of 12nm, respectively. The amount of adsorbed enzymes was found to be dependent on the molecular size of enzymes. The amount of adsorbed catalase was more than two times that of adsorbed papain, suggesting that MCFs with large pores is a suitable host for large enzymes adsorption. The blocking of pores which resulted from aggregation of enzymes in the windows of MCFs and the higher leaching of enzymes form MCFs may be the reason of lower papain adsorption capacity in MCFs.

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