Apr 2025, Volume 24 Issue 4
    

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  • Jin Zhang, Xingbin Ou, Donghua Yang, Zhifu Sun

    High-energy shot peening (HESP), a method to produce severe plastic deformation by high velocity flying balls, was applied on die cast magnesium alloy AZ91D. Effects of surface nanocrystallization by HESP and heat treatment at different temperatures were investigated. The microstructure evolution was conducted using X-ray diffraction (XRD) and field emission scanning electronic microscopy (FESEM). The hardness was measured by microhardness tester. The experimental results show that surface nanocrystrallization of AZ91D obtained by HESP would lead to the increase of microhardness. Low temperature heated at 100 °C for 1 h do not change the property obviously. However, both the microstructure and microhardness vary greatly after heat treatment at 400 °C for 1 h.

  • Zengzhi Zhang, Na Gu, Jifei Zhang

    Common clay, Kaolin and Bentonite were used as additives to prepare water-transmitting coating fiber, respectively, and the water-transmitting characteristic of coating fiber was studied. Different water-transmitting coating fibers were prepared by coating fiber using coating material with different mass proportions of additives to adhesive. And the coating materials were made from three kinds of inorganic clays as additives respectively and polyvinyl alcohol (PVA) as adhesive. Furthermore, the surface morphology and water-transmitting capacity of coating fiber were studied by SEM, Perkin Elmer Diamond S II thermal multi-analyzer and instrument for quick measurement moisture M30. The experimental results indicate that water-transmitting coating fibers made from three kinds of clays all have water-transmitting capacity. The surface of water-transmitting coating fiber prepared by common clay T is continuous and compact, and the water-transmitting effect is better than coating fibers made from other clays.

  • Lixin Cao, Xundao Yuan, Shiquan Xi

    The film forming behavior on the interface between air and hydrosol of Fe2O3 nanoparticles was investigated by the surface pressure-time isotherms, the surface pressure-trough area isotherms, Brewster angle microscopy and transmission electron microscopy. It is found that the freshly prepared hydrosol of Fe2O3 nanoparticles is not stable. The surface pressure increases with the aging time and finally approaches a constant, and the smaller the concentration is, the smaller the surface pressure is stabilized at and the shorter the time the hydrosol reaching stable needs. The surface pressure also increases with compression until collapsed, and the longer the hydrosol is aged, the higher the collapsing pressure is. A uniform and compact film composed of nanoparticles with an average diameter of about 2–3 nm on the air-hydrosol interface is observed by Brewster angle microscope and transmission electron microscope.

  • Changping Min, Xuefeng Ruan, Huamin Zou

    The elastic microstrains in a crystallite of electrodeposited nanocrystalline copper were investigated by analyzing the high resolution electron microscopy (HRTEM) image. The microstrain was considered as consisting of two parts, in which the uniform part was determined with fast Fourier transformation of the HRTEM image, while the non-uniform part of the microstrain in the crystallite was measured by means of peak finding. Atomic column spacing measurements show that the crystal lattice is contracted in the longitudinal direction, while expanded in the transverse direction of the elliptical crystallite, indicating that the variation of microstrain exists mainly near the grain boundary.

  • Chunmei Gao, Zhiyu Wang, Zhongping Yu, Bo Ye, Bo Liu, Xianping Fan, Guodong Qian

    Highly crystalline orthorhombic Bi2WO6 powders were hydrothermally synthesized from aqueous solutions of Na2WO4 · 2H2O and Bi (NO3)3 · 5H2O over a wide range of pH. The effect of pH on morphologies, sizes and properties of the Bi2WO6 crystals was investigated. The band gaps of the as-prepared Bi2WO6 were determined from the onset of the absorption edge of UV-vis diffuse reflectance spectra. The methyl orange photodegradation was employed as a probe reaction to test the photocatalytic activity of the as-prepared samples under visible light irradiation. The photocatalytic activities of methyl orange degradation under visible light irradiation are strongly dependent on the pH used in the synthesis. The highest efficiency is observed at pH=7.

  • Junting Luo, Riping Liu

    Amorphous nano-sized silicon nitride powders were sintered by liquid phase sintering. The influences of the additives of Y2O3 and Al2O3 prepared by two different ways, the polyacrylamide gel method and the precipitation method, were investigated. The grain sizes of the additives prepared by the first method were finer than those of prepared by the latter method. When sintered at the same temperature, 1700°C, the average grain size of the silicon nitride is 0.3 μm for the sample with the former additives, which is much finer than the one with the latter additives. The density of additives prepared by precipitation method is clearly lower than those of prepared by polyacrylamide gel method.

  • Yanqing Guan, Huimin Tao, Yuechuan Li, Wenwen Wang, Zhibin Li, Changlian Peng

    A novel way for photo-immobilization with interferon- α (IFN- α) on the surface of polyurethane (PU) material, which makes PU condom more effective function in the future, was investigated. A kind of photoactive arylazide-4-azidobenzoic acid was modified to IFN- α with the confirmation of IR and Raman spectrum. Micro morphology of the photo-immobilized cell factors was observed by FESEM as well as CSLM at the level of nanometer. Finally, the product with elementary test of anti-microbial was also evaluated.

  • Lixia Yang, Wenguang Zhang, Tao Gu, Jun Feng

    The influence of acetic acid on dynamic behavior of hydrolazation and film forming of an expoxy-silane compound (γ-GPS) was investigated by conductivity meter, IR and AFM. The experimental results show that there is an optimal pH value(pH=4–5) for hydrolysis of silane solution, and with the prolongation of hydrolytic time, the promotion of acetic acid on the hydrolyzation of silane solution become more obvious. During the adsorption and film forming process, acetic acid could promote the formation of Si-O-Fe bond, which activates hydroxyl group of silanol unit and facilitates this hydroxyl group to react with adjacent silanol unit forming linear condensation polymers.

  • Shengkui Zhong, Fengpeng Li, Jiequn Liu, Yanhong Li, Xingsheng Deng

    Y-doped LiVPO4F cathode materials were prepared by a carbothermal reduction(CTR) process. The properties of the Y-doped LiVPO4F samples were investigated by X-ray diffraction (XRD) and electrochemical measurements. XRD studies show that the Y-doped LiVPO4F samples have the same triclinic structure as the undoped LiVPO4F. The Li extraction/insertion performances of Y-doped LiVPO4F samples were investigated through charge/discharge, cyclic voltammogram (CV), and electrochemical impedance spectra(EIS). The optimal doping content of Y is x=0.04 in LiY xV1−xPO4F system. The Y-doped LiVPO4F samples show a better cyclic ability. The electrode reaction reversibility is enhanced, and the charge transfer resistance is decreased through the Y-doping. The improved electrochemical performances of the Y-doped LiVPO4F cathode materials are attributed to the addition of Y3+ ion by stabilizing the triclinic structure.

  • Shaomin Lei, Gaoli Guo, Bihua Xiong, Wenqi Gong, Guangjun Mei

    The photo-induced antibacterial capacity of montmorillonite supported titanium dioxide (TiO2/Mmt for short) was evaluated by using Escherichia coli and Staphylococcus aureus as modal organisms. The bactericidal activity of TiO2/Mmt was examined by cell viability assay under different illumination modes. Atomic force microscopy (AFM) and total organic carbon/Total nitrogen (TOC/TN) analyses were employed to investigate the mechanism of the photocatalytic bactericidal process qualitatively and quantitatively. The kinetic data show that TiO2/Mmt has excellent antibacterial performance, and about 99% of both bacteria cells are inactivated within 75 min illumination. The AFM images demonstrate that the bacterial cells are irreversibly decomposed and some cell components are dissolved. Therefore, the content and phase of carbon and nitrogen in the solution are changed after photocatalytic reaction.

  • Xuanjun Wu, Jizu Yuan, Yongfu Yu, Yanxiong Wang

    The montmorillonite, a form of layered silicate, was successfully intercalated into polylactide (PLA) matrix through solvent-casting technique. In addition, PLA/MMT nanocomposite films were produced, in which homogenous distribution of the silicate lamellae plays a key role in the mechanical properties of the films. A small amount(5wt%) of OMMT intercalated into the PLA matrix resulted in their flexibility enhancement, from 3.68%(pure PLA film) to 352.65%. The results of wide-angle X-ray diffraction (WAXD) patterns confirmed that the silicate interlayer distance increased from 3.044 nm (for OMMT) to 3.56nm (for 5wt%, maximum) with increasing OMMT contents, but decreased to 3.319 nm when OMMT content was over 8wt%. FT-IR also verified the molecular-level associations between PLA chains and OMMT lamellae by vibration variances of hydrogen bonding. DSC thermograms demonstrated that thermal stabilities of the nanocomposite films enhanced, due to the silicate lamellae dispersed into PLA matrix.

  • Xiongjun Shen, Jianming Ruan, Zhongchi Zhou, Zhicheng Zeng, Lesi Xie

    A micro-envioment for nerve cells and tissue growth were designed and constructed via surface modification of poly(L-lactide-co-glycolide)(PLGA) with chitosan and hydroxyapatite(HA). The poly(L-lactide-co-glycolide)/chitosan/hydroxyapatite (PLGA/chitosan/HA) conduits were manufactured by a combined solvent casting and particulate leaching technique. The conduits were highly porous with an interconnected pore structure and 76.5% porosity. Micropores with 50–100 micrometer diameter were formed in the conduits. In vivo application of PLGA/chitosan/HA conduits for reconstruction of 10 mm sciatic nerve defect was assessed by the walking track analysis, the quantifying of the wet weight of tibialis anterior muscle and the histological assessment. The conduits in host rats in vivo can not only be an effective in promoting regenerating of nerves but can also lead to favorable nerve functional recovery.

  • Yuxiang Gao, Xingmin Ji, Yihua Yin, Hui Dong, Hua Zheng

    A series of cross-linked gels of Poly(N-isopropylacrylamide) [P(NIPAAm)] and Poly(methacr-ylic acid)[P(MAA)] homopolymers and P(NIPAAm-co-MAA) random copolymers were synthesized based on NIPAAm and MAA using 4,4-Bis-(methacryloylamino) azobenzene (BMAAB) as a cross-linker. The swelling behavior of these hydrogels in different pH buffer solutions was studied. The influential factors of the gels including composition of NIPAAm and MAA, pH and temperature upon swelling behavior were investigated. The obtained gels not only hold pH and thermometrical sensitivity, but also take on enzymatic sensitivity due to the cross-linker could be degraded by enzymes of colon. Swelling equilibrium degree of copolymers was very low in acidic medium, which could avoid drug releasing due to biggish swelling of carrier in stomach. Hydrogels would partly swell owing to higher pH value in small intestine. When arrived in colon, hydrogels completely swelled, meanwhile, azoenzymes located would degrade azo-bonds of polymeric network and then drug released in colon.

  • Lili Wu, Chaocan Zhang, Jinming Guo, Shanjun Gao

    A series of thermoreversible konjac glucomannan gels crosslinked by organic borate were prepared. Required amount of hydrophilic SiO2 was added into the konjac glucomannan solutions before the crosslinking reaction. The gel network was formed through the crosslinking reaction between borate ions dissociated from organic borate and the cis-diol hydroxyl groups on the mannose units of polysaccharide chains. The rheological properties of the complex gels were studied by dynamic viscoelastic measurement. The gelation kinetics of the complex gels was studied and the critical gelation points of the gels were exactly determined by the Winter-Chambon criterion. The effects of temperature and composite ratio on the shear storage modulus (G′), the loss modulus (G″) and the sol-gel transition points were investigated.

  • Lingyan Zhang, Tingting Wei, Huijie Chen, Weiqiang Lai, Junfen Bu

    The mechanical and thermal properties of polypropylene (PP)/muscovite/low-density polyethylene (LDPE)/polypropylenegraftmaleic anhydride (PP-g-MAH) ternary composites were investigated. In PP matrix, muscovite, LDPE, and PP-g-MAH were added as strengthening agent, toughening agent, and compatibilizer, respectively. The effects of dosages of the added materials were analyzed. The experimental results show that the optimum recipe of PP/muscovite/LDPE/PP-g-MAH composites is100/10/6/20 (mass ratio). Compared with the pure PP, the mechanical properties of PP/muscovite/LDPE/PP-g-MAH composites, including notched impact strength, Rockwell hardness and flexural strength, are improved. Although tensile strength is slightly decreased, they have better toughness. Filled with muscovite, the heat-resistance and heat-decompostion of the composites are improved.

  • Xinkuan Wang, Yuhong Liu, Jianbin Luo, Guoxin Xie

    The tribological properties of perfluoro and non-perfluoro alkylsilane molecular films were investigated and compared detailedly. Their surface properties were characterized by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and contact angle (CA) measurement. A ball-on-disk tribometer was used to study the frictional properties of these alkylsilane monolayers. The experimental results reveal that the alkylsilane molecular films are good candidates to decrease friction and they have good capability to endure rigorous shear forces. Perfluoro alkylsilane molecular films are bonded better with the Si substrate than the simple hydrocarbon ones. The effects of sliding velocity and normal load on friction coefficient are evident and the friction coefficient increases with the increase of the sliding velocity. However, friction coefficient decreases with the increase of normal load initially and then increases, indicating there exists a critical normal load for the load effect.

  • Lijie Dong, Liping Liu, Yongsheng Niu, Chuanxi Xiong, Qingming Zhu, Yun Liu

    A series of new polyamides 3a–d containing aryl-azo, ether and sulfone groups in the main chain were synthesized from bis[4-(4-aminophenoxy)phenyl sulfone] 1 and several azo aromatic diacyl chlorides 2a–d by the low temperature solution polycondensation technique. FTIR spectroscopy, nuclear magnetic resonance (NMR) and elemental analyses confirmed the structure of these polymers. Owing to the aryl and amide groups in the main chain, these polymers exhibit photochromic properties as well as excellent thermal stabilities. The transition temperatures (T g) are between 242 and 265 °C, and the char yields at 800 °C in nitrogen atmosphere were above 39%. Based on incorporation of flexible ether linkages and polar sulfone groups, the polyamides show desirable solubility in organic solvents such as DMAc, N,N-dimethylformamide (DMF), N-methyl-2-pyrroidinone (NMP) and dimethylsulfoxide (DMSO). And it is exemplified that polyamide containing 2 and 2′ substitutes performed better solubility.

  • Yajing Ye, Litong Zhang, Kehe Su, Laifei Cheng, Yongdong Xu

    Doping of boron, nitrogen, aluminum and titanium in the SiC (310) twin boundary was investigated, and the first-principle calculation was used to analyze the underlying mechanism of excellent creep resistance and strength of Sylramic and Tyranno SA SiC fibers. The electronic structures were also analyzed and compared. The results of Mulliken overlap populations, electron density differences and density of states reveal that doping of B or N atom reinforces SiC GBs bonding, however, doping of Al or Ti atom weakens SiC GBs bonding. The reinforced SiC GBs will largely prevent atoms from sliding near GBs. The experimental results would be one of the reasons which lead to the reinforcement of either creep resistance or the strength of SiC fibers.

  • Guangjun Mei, Peng Rao, Mitsuaki Matsuda, Toyohisa Fujita

    A novel process for separation of red (Y2O3:Eu3+), blue(BaMgAl10O17:Eu2+) and green (CeMgAl10O17:Tb3) rare earth fluorescent powders was proposed. At first, the blue powder can be extracted selectively from an aqueous solution using a chelating collector 2-thenoyltrifluoroacetone (TTA) dissolved in heptane at alkaline pH condition, then, chloroform was used for extracting the green powder into organic phase. The red phosphor remains in aqueous phase with potassium sodium tartrate depressant (PST). Therefore, three phosphors can be separated successfully from their artificial mixtures by liquid/liquid extraction, and grades and recovery of separated products reach respectively as follows: red is 96.9% and 95.2%, blue is 82.7% and 98.8%, green is 94.6% and 82.6%.

  • Hualin Xie, Kelong Huang, Xidu Nie, Liang Fu

    Trace elements were determined in high purity gold by high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS). Sample were decomposed by aqua regia. To overcome some potentially problematic spectral interference, measurements were acquired in both medium and high resolution modes. The matrix effects due to the presence of excessive HCl and Au were evaluated. The optimum conditions for the determination was tested and discussed. The standard addition method was employed for quantitative analysis. The detection limits range from 0.01μg/g to 0.28μg/g depending on the elements. The method is accurate, quick and convenient. It has been applied to the determination of trace elements in high purity gold with satisfactory results.

  • Lijiu Wang, Shanyu Zhao

    The synthesis procedures and physical properties of the ambient dried hydrophobic silica aerogels by using different contents of ethanol (EtOH)/trimethylchlorosilane (TMCS)/n-Hexane as surface modification agent were investigated. One-step solvent exchange and surface modification were simultaneously progressed by immersing silica hydrogels in EtOH/TMCS/n-Hexane solution. It is found that microstructures as well as properties of silica aerogels like porosity, specific density and specific surface area are affected by the contents of surface modification agent in the sol from the results of SEM, TEM morphology, FT-IR chemical structure, BET surface area and BJH pore size analyses. The volume of TMCS is of 10% and 20% of hydrogels, and the final product is hydrophilic xerogels. When TMCS’s percent (v/v) is elevated to 75%–100%, hydrophobic silica aerogels with good performance are synthesized, the porosities of aerogels are in the range of 93.5%–95.8% and the average pore size diameter is less than 20 nm.

  • Yuanyuan Xu, Jimin Wu, Jing Guan, Xizheng Zhang, Zhihong Li, Pengfei Wang, Ruixin Li, Yong Guo, Bo Ning, Shujie Huang

    The aim of the present study was to compare one-step method to EDC/NHS crosslinking (EDC/NHS group) and one-step simultaneous method to EDC/NHS crosslinking and heparin immobilization (EDC/NHS- Heparin group) in improving physiochemical and biological properties of native collagen sponge (Control group). Modified collagen sponge overcome the disadvantages of native collagen sponge. IR spectra suggest the change of the functional groups. DSC data indicate that the stability of caloric transformation in EDC/NHS group is slightly higher than that of EDC/NHS-Heparin group. The crosslinking degree, stability against enzymes, stability in morphologically and biomechanical properties of EDC/NHS-Heparin group are higher than those of EDC/NHS group, whereas, the water-binding capacity in EDC/NHS-Heparin group is lower than that of EDC/NHS group. HUVECs in EDC/NHS-Heparin group scaffold proliferate fast, migrate well and distribute uniformly. One-step simultaneous method gains the better effects in above aspects, heparinized collagen matrices increase in angiogenic potential and suit for defect repairing and tissue engineering.

  • Huajun Duan, Lianmeng Zhang, Jun Wang, Xiaoli Yang, Xiang Wang

    HDI trimer was firstly used to improve the mechanical properties of hydroxyl- terminated unsaturated polyester (UP). Mechanical properties measurements performed on the cured materials demonstrate a distinct improvement in intensity and toughness in the presence of HDI trimer and shows the change trends of increase and then decrease. The morphological analysis of the fracture surfaces shows that the micro-phase separated structures appear in modified UPR systems and changed from dendritric, dimple and to cystiform structures with the increase of HDI trimer content. The presence of the cystiform structures made the modified UPR systems present the best properties.

  • Lijun Chen, Hongxin Shi, Juping Xiang, Hongke Wu

    Using methyl methacrylate (MMA), butyl acrylate(BA) and hexafluorobutyl acrylate(HFBA) as main raw materials, we prepared self-crosslinked fluorocarbon polymer emulsion with core-shell structure via soap-free emulsion polymerization when the conception of particle design and polymer morphology was adopted. Moreover, the influence of mole ratio of BA to MAA, pH value on the oligomer was studied. And the effects of the added amount of oligomer, self-crosslinked monomer and HFBA, mass ratio of BA to MMA, reaction temperature and the initiator on the polymerization technology and the performance of the product, were investigated and optimized. The structure and performance of the fluorocarbon polymer emulsion were characterized and tested with FTIR, TEM, MFT and contact angle and water absorption of the latex film. The experimental results show that the optimal conditions for preparing fluorocarbon polymer emulsion are as follows: for preparing the oligomer, mol ratio of BA to MAA is equal to 1.0: 1.60, and pH value is controlled within the range of 8.0 and 9.0; for preparing fluorocarbon polymer emulsion, the added amount of oligmer[P(BA/MANa)] is 6%; mass ratio of BA to MMA is 40: 60; the added amount of self-crosslinked monomer is 2%, the added amount of HFBA is 15%; reaction temperature is 80 °C; the mixture of potassium persulfate and sodium bisulfite is used as the initiator. The film-forming stability of the fluorocarbon polymer emulsion and the performance of the latex film, which is prepared with the soap-free emulsion polymerization, are better than that prepared with the conventional emulsion polymerization.

  • Rui Xu, Kanggen Zhou, Minyi Hu

    A novel method of electroless silver coating on copper powders was reported, in which hydrazine was used as the reducing agent, and had some advantages such was used as inhibiting the substitution reaction and reducing consumption of copper powders. In the processes of sensitization and activation, AgNO3 replaces the conventional PdCl2, which solves the impurity of bath. Oxide film on the surface of copper powders was tested by chemical analysis. Ag element tested by XRD and XRF is in the form of Ag0 and exists on the surface of copper powders, which acts as catalyzer in reduction reaction. Morphology and composition of the coating were characterized by SEM and XRD respectively.

  • Hairong Yin, Chunxiang Zhang, Liying Liu, Guoping Chen, Baojun Tang

    The glass-forming region of B2O3-Al2O3-SiO2 (BAS) glass heavily doped with rare earth oxides was investigated by an effective method, and the chemical stability was investigated by powder method. Influences of rare earth oxides on the glass-forming ability and the chemical stability of the BAS glass were also discussed. The experimental results show that the BAS glass-forming region expands firstly with the increase of the Tb2O3 content up to 30mol% and then shrinks. The acid-resistant capacity of the BAS glass doped with rare earth oxides is the lowest, the water-resistant capacity is secondary, and the alkali-resistant capacity is the best. Besides, the glass chemical stability can be improved by doping appropriate amount of rare earth oxides. Moreover, the stronger the ionic polarization ability of the rare earth ions is, the better the chemical stability of the BAS glass will be.

  • Shuiping Wang, Rui Weng, Chonghui Wang, Ping Yang

    A fluoride-containing organic silane was synthesized by the reaction of N-ethyl-N-hydroxy-ethyl perfluorinated octyl sulfonamide (EHPOS), N-(β-aminoethyl)-γ-aminopropyl trimethoxy silane (ATS) and cis-butenedioic anhydride (CA). The experimental results show that the yield of product is up to 87% when the molar ratio of EHPOS: CA: ATS is 1: 1.05: 1.1. EHPOS and CA were maintained at 115 °C for 3 hours, then after cooling the reaction solution to 75 °C, ATS was added and reacted for another 3.5 hours at 145 °C. The structure of the product and thermal properties were characterized by Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA), respectively. Results show that fluoride-containing organic silane has excellent thermal stability below 185 °C.

  • Keqing Fu, Jiayi Liang, Hongyan Xu, Rong Bai

    An ultrasonication assisted sol-gel processing route for MWNTs/Alumina was proposed. Using aluminum ethoxide as an alumina precursor and ethanol/water as a solvent, the duration of the transformation from sol to gel under ultrasonication can be controlled by adjusting the water content. Purified MWNTs added under ultrasonication should be functionalized by alcohol at first and a well dispersion in alumina sol could be attained under the help of ultrasonic. With the evaporation of ethanol, sol transfers to gel and MWNTS dispersion can be kept in gel. Gel and calcine-powder show that individual MWNTs are enwrapped by amorphous alumina. As-received powders after a following heating-treatment under vacuum shows a good high stability for a glass coat formed on MWNTs. Raman results show the processing route has no obvious effect on the structure of MWNTs, even a high temperature (1273K) treatment is done under vacuum.

  • Jianfeng Wu, Jian Li, Xiaohong Xu, Lanfang Yang, Jufang Wu, Fang Zhao, Chuanguo Li

    A new type of high temperature energy storage material was obtained through the melt infiltration method, using compounding SiC ceramic foam as matrix and Na2SO4 as phase change material. The resulting composite material was measured by XRD, SEM, TG-DSC methods. The experimental results indicate that the composite is composed of silicon carbide, sodium sulfate and square quartz, and no chemical reactions occurs between Na2SO4 and SiC matrix. Na2SO4 has a good bonding with the SiC ceramic foam matrix. As the composite material is characterized by high thermal energy storage density and high thermal conductivity, it is suit for energy storage under high temperature.

  • Huiyan Wang, Gaoke Zhang, Huihu Gan, Yuanyuan Gao

    The ibuprofen-rectorite composites were prepared by the solution intercalation method using ibuprofen and rectorite as raw materials, and were characterized by X-ray diffraction (XRD) analysis, Fourier transform infrared analysis and scanning electron microscopy (SEM). The experimental results show that the ibuprofen is intercalated into the interlayer spaces of rectorite. The values of the (001) peaks of the ibuprofen-rectorite composite are larger than that of Na-rectorite and reach the largest when the reaction time and ibuprofen amount is 2 h and 0.36 g, respectively. The layered structure of Na-rectorite is destroyed to some extent with the intercalation of ibuprofen into the interlayer space in the structure of Na-rectorite. A part of ibuprofen in the ibuprofen Na-rectorite covers on the surface of Na-rectorite besides some ibuprofen enters into the interlayer space.

  • Jun Liu, Changwei Xu, Yang Ou, Hong Qi

    Glass ceramics was made by the one-time sintering method using the main raw material of iron tailings. On the basis of quaternary system of CaO-MgO-Al2O3-SiO2, using DTA, XRD and SEM, the effects of different nucleating agents and mixing amounts as well as heat treatment on the crystallization of tailings glass ceramics were studied. The experimental results show that, nucleating agent and heat treatment are two necessary conditions for one-time sintering preparation of tailings glass ceramics namely, only adding nucleating agent or experiencing heat treatment, the quaternary system can not crystallize. The composite nucleating agent consisting of Cr2O3 and TiO2 can further lead to the crystallization of the CaO-MgO-Al2O3-SiO2 quaternary system at the lower temperature, with the major phase of diopside. In the range of mass content, 0%–4%, crystal intensity and crystal content grow. But when mass content is more than 4%, the crystal size will become coarser and the crystal distribution will be less regular. Different heat treatment regimes do not change the composition of the crystalline major phase in the glass ceramics crystallization of CaO-MgO-Al2O3-SiO2 system. In the range of 30–60 minutes, with the extension of nucleation and crystallization, crystallization degree enhanced, but if the holding time surpasses 60 minutes, the crystallization is worse.

  • Decheng Zhang, Dongyu Xu, Xin Cheng, Wen Chen

    The influences of water/cement ratio and admixtures on carbonation resistance of sulphoaluminate cement-based high performance concrete (HPC) were investigated. The experimental results show that with the decreasing water/cement ratio, the carbonation depth of sulphoaluminate cement-based HPC is decreased remarkably, and the carbonation resistance capability is also improved with the adding admixtures. The morphologies and structure characteristics of sulphoaluminate cement hydration products before and after carbonation were analyzed using SEM and XRD. The analysis results reveal that the main hydration product of sulphoaluminate cement, that is ettringite (AFt), decomposes after carbonation.

  • Hui Li, Delong Xu

    To use fly ash and coal waste effectively, the current technologies for reprocessing and recycling these wastes into eco-building materials were reviewed, such as utilizing fly ash as the component of fly ash cement and low heat cement after the processes of separation, removal of carbon remains and fine comminution, calcining coal waste into kaolin and meta-kaolin with suspension technology, and preparing clinkerless alkali-activated geopolymer materials with fly ash and meta-kaolin.

  • Jianying Yu, Xilin Wang, Dongliang Kuang, Henglong Zhang

    Styrene-butadiene-styrene (SBS) modified bitumen crack filling material with organophilic montmorillonite (OCFM) was prepared by melt blending. X-ray diffraction analysis shows that the interlayer spacing of organophilic montmorillonite (OMMT) in OCFM is widened and an exfoliated structure may be formed. Thermal-oxidative aging behavior of OCFM and SBS modified bitumen crack filling material (SCFM) was investigated. The experimental results indicate that the rate of thermal-oxidative aging of OCFM is much slower than that of SCFM, which can be attributed to barrier of exfoliated structure of OCFM to oxygen.

  • Hedong Li, Shilang Xu, Christopher K. Y. Leung

    The tensile and flexural properties of polyvinyl alcohol (PVA) fiber reinforced ultra high toughness cementitious composite (UHTCC) were investigated. The composite, tested at the age of 14 d, 28 d and 56 d, shows extremely remarkable pseudo strain hardening behavior, saturated multiple cracking and ultra high ultimate strain capacity above 4% under uniaxial loading. Also, the corresponding crack widths are controlled under 50 μm even at 56 days age. In the third point bending tests on thin plate specimens, the composite shows ultra high flexural ductility and multiple cracking on the tension surface. The high ultimate flexural strength/first tensile strength ratio of about 5 verifies the pseudo strain hardening behavior of UHTCC. SEM observation on fracture surfaces provides indirect evidence of optimal design for the composite.

  • Weiguo Shen, Tao Zhang, Jingqiang Hu, Wei Ma, Mingkai Zhou

    Cement paste with low water/cement ratio of 0.3 was observed using AFM. It is found that C-S-H has self similarity trait from scanning scale 20 μm×20 μm down to 300 nm×300 nm, and the feature of C-S-H at large scale is very similar to those smaller scales. It can be concluded that C-S-H is composed with some fundamental spherical globule, the fundamental globules agglomerate into bigger ones, moreover the bigger ones agglomerate into even bigger one. A C-S-H globule fractal model was put forward to describe the self similarity of the C-S-H globule, which can be used to reveal how the C-S-H globule contacts with each other.