Advanced Materials Research Vols. 150-151

Abstract: In the present work we present the results of a simple laboratory experiment which fulfils the mechanical conditions of formation of fracture and faults in earthquakes and also helps us understand the relation between inter- and intraplate earthquakes. Although many experimental investigations have been undertaken in an attempt to understand this relationship, they were not successful due to the difficulty in duplicating the conditions causing earthquakes using experimental methods. We discovered that the stress field around a subsurface crack growing under rolling contact fatigue fulfils the mechanical conditions of a plate subduction boundary, and also that subsurface crack branching is similar to the fracture of earthquake faults.

Abstract: ICPF (Ionic Conducting Polymer Film) is a kind of smart film and has the characteristics of flexibility, good response and being driven by a low voltage. In order to illuminate the deformation dynamics of ICPF, the curvature of a thin strip ICPF under stepwise application of electric field is formulated according to Flory’s gel swell theory. The interplay mechanism of the deformation of gel, permeation of water and the transport of ions is described. A novel fish-like flexible micro-robot whose tail is actuated by ICPF is presented. According to the Pseudo-Rigid-Body-Dynamic-Model (PRBDM) the frequency analysis of the micro-robot is investigated, and then, the relation between the structure parameters and the natural frequency of the tail is theoretically derived and some analysis and experiment graphs about the angle displacement of the tail are performed.

Abstract: The chitosan(CS)/polyurethane(PU) blend nanofibers have been prepared for the first time by electrospinning. Formic acid (FA) and Hexafluoroisopropanol (HFIP) were found to be the co-solvent for electrospinning. The CS/PU blend solutions in various ratios were studied for electrospinning into nanofibers. The diameter and morphology of the fibers were shown by scanning electron microscope (SEM). It was found that the average diameter of the chitosan/PU blend fibers became larger, and the morphology of the fibers became finer with the content of PU increasing. To show the molecular interactions, CS/PU fibers were characterized by Fourier transform infrared spectroscopy (FT-IR). Moreover, the antibaterial activity of blend nanofibers against Escherichia coil (E.coil) was measured via optical density method. The blend nanofibers exhibited satisfying antibacterial activity against E.coil, even the chitosan concentration was only 5wt%. Therefore, the spun nanofibers are expected to be used in the native extracellular matrix for tissue engineering.

Abstract: The properties and void structures of foamed concretes prepared from portland cement, fly ash, steel slag and foam agent were investigated. The results show that substituting cement by steel slag resulted in little change in dry bulk density, but reduced the compressive strength; on the other hand, when cement was substituted with fly ash, though the dry bulk density decreased, the compressive strength increased as the proportion of substitution increased from 30%to 45%. Increasing the volume fraction of the foam decreased greatly the dry bulk density and the compressive strength, and reduced the thermal conductivity as well. Image analysis on the air void structure shows that the larger air void fraction, the larger average void size and lower void roundness. There is a close correlation between the average mean Feret diameter and the average shape factor.

Abstract: The DPCC(deformation processed Cu-based in-situ composite) behaved better combined performance. In this paper, Cu-10Fe-1.5Ag and Cu-10Fe-1.5Ag-0.1Zr in-situ composites were prepared using different forming processes and annealing techniques. The microstructure evolution was explored by SEM during the plastic deformation. It was found that Fe fibers were produced during drawing process and changed from trees dendrite to fiber structure in the form of flake. The effect of Zr on thermal stability of composite was analyzed also. It was shown that the adding of Zr element was helpful to increase the thermal stability of Cu-Fe composite by multi elements compound.

Abstract: Poly(L-lactic acid)-co-bisphenol-A epoxy resin/vermiculite nanocomposites（PLLA-co-bis A /VMT）were prepared by in-situ melt polycondensation of L-LA in the presence of amino-modified vermiculite. The fourier transform infrared (FTIR) spectra were used to investigate molecular interactions between the modified vermiculite and PLLA. The detailed thermal property and crystallization behavior of samples were studied by using polarized optical microscopy (POM), differential scanning calorimetry (DSC) and thermogravimetric analyzer (TGA). The result indicated that the thermal stability, overall crystallization rate and spherulitic texture of PLLA-co-bis A were strongly influenced in the presence of vermiculite particles.

Abstract: Multiferroic Bi1-xGdxFeO3(x=0, 0.05, 0.1, 0.15, 0.2) ceramics were prepared by conventional solid state reaction method. For all the samples prepared, they exhibit magnetoelectric effect at room temperature, and the dielectric constant and dielectric loss decrease with increasing frequency in the range from 10000Hz to 1 MHz from a typical orientational dielectric relaxation process. It has been found that both dielectric constant and dielectric loss are strongly dependent on the Gd3+ content. And substitution of Bi with rare earth Gd helps to eliminate the impurity phase in BiFeO3 ceramics.,

Abstract: It was reported that suspension polymerization experiment of methyl methacrylate/ styrene copolymer in inorganic/organic ternary composite system. Some factors on modification of methacrylate/styrene copolymer were studied and optimized synthesis technics was found. The configuration and thermal performance of round bead copolymer products was analyzed by FT-IR and thermogravimetry. Methyl methacrylate/Styrene copolymer dispersed in O-MMT suspension polymerization system showed there was evident improvement about its thermostability.

Abstract: Poly(allylamine phosphate) (PAP) was synthesized by solution polymerization using allylamine phosphate (AP) as monomer, 2,2’-azo-bis-2-amidinopropane dihydrochloride (AAP•2HCl) as initiator, respectively. PAP reacted with concentrated hydrochloric acid and it converted into poly(allylamine hydrochloride) (PAH). The effects of varying the concentrations of initiator and monomer on the polymerization conversion were investigated in detail. The chemical structure and thermal property of the polymer were studied by Fourier transform infrared spectrometer (FTIR), nuclear magnetic resonance spectrometer (NMR), thermogravimetric analyzer (TGA), differential scanning calorimeter (DSC), X-ray diffractmeter (XRD), respectively. PAH was prepared because of the disappearance of the stretching vibration absorption peaks and deformation vibration absorption peak of C-H bonds in -C=CH2 at 3020cm-1, 3085cm-1 and 1310cm-1 in the FTIR spectra. The three peak areas and their chemical shifts were consistent with the three kinds of hydrogen atoms in polymer formula in 1H NMR spectrum, which proved that PAH was synthesized. PAH had three decomposing stages and it decomposed completely at 700oC. The glass transition temperature (Tg) of PAH increased with decreasing concentration of initiator. The conversion of monomer increased with the increasing concentrations of initiator and monomer.

Abstract: Titanium dioxide thin film has been successfully synthesized deposited on ITO glass substrates by the sol–gel dip-coating method using freeze drying technique. The precursor and TiO2 film were characterized using XRD, AFM and UV-vis absorption spectra analysis technologies. The XRD result demonstrates that the TiO2 film is well crystallized and consists of anatase phase only with (101) plane. The morphology of the nanoparticles of TiO2 thin film is spherical shape with grain size of 30.1 nm in average diameter and the surface of the TiO2 film is smooth. There is a strong wide UV absorption band around 387 nm and the calculated band gap (Eg) value of the TiO2 thin film is about 3.18 eV. The water contact angles for the thin film was only about 12°. The freeze drying-assisted sol-gel technique offers a novel process route in treating hydrophilic glasses for self-cleaning building materials and would be widely application for building energy saving.