Abstract: Chrome-tanned collagen fiber is the major solid waste of leather industry which is difficult to biological degradation and would caused serious pollution to the environment. However, the collagen fibers as a natural biological polymer materials, has unique properties of surface reactivity that the other polymer materials are not available. In this paper, the composite film of chrome-tanned collagen fiber- polyurethane (PU) were prepared is owing to H2O induced phase separation, and measured water vapor permeability, permeability, mechanical properties and microstructure. The results showed that the composite film of chrome-tanned collagen fiber-PU have continuous porous structure, which can improve the water vapor permeability and permeability of film, but reduce the mechanical properties of film. Thermal gravimetric analysis (TGA) showed that the thermal effect of collagen fiber and PU did not change significantly, so composite of collagen fiber and polyurethane by H2O induced phase separation belongs to physical process. The result demonstrates that this composite film has continuous porous structure, and collagen fibers with unique properties of surface reactions, so this material have potential applications in many fields.
Abstract: In the present work, a GCMS method coupled with Molecular imprinting technique was developed for the simultaneous determination of five organophosphorus pesticide residues (i.e., diazinon, malathion, phosphamidon, isofenphos-methyl and quinalphos) in environmental water. In order to obtain a highly selective recognition of OPPs, we synthesized molecularly imprinted polymers (MIPs) using malathion as the template, methacrylic acid as the monomer and ethylene glycol dimethacrylate as the crosslinker. After polymerization, molecularly imprinted solid-phase extraction (MISPE) was used for the selective preconcentration of OPPs. The specificity of MIPs and non-imprinted polymers were investigated. The use of MISPE improved the accuracy and precision of the GCMS method. The recoveries of OPPs extracted from water sample at a 1μg/mL spike level were in the range of 82%~97%. The results showed that MIPs enable the selective extraction of OPPs successfully from water sample, and demonstrated the potential of MISPE for selective and cost-effective sample pretreatment.
Abstract: The polyacrylate emulsion coating modified by nano-silica was prepared by In-situ method. Tetraethoxysilane (TEOS) was added as the precursor of SiO2 in the late of the emulsion polymerization. The structure and properties of emulsion and latex film were characterized. The results showed that the nano-hybrid silica/polyacrylate emulsion coating with good performance can be prepared by In-situ method. FTIR analysis indicated that the -Si-O-Si- structure has embodied in the coating film. The particle diameter of emulsion is 378nm when nano-SiO2 content is 6% and the dispersing index is 0.164. The mechanical loss peak temperature (Tp) of coating film with 6% nano-SiO2 is 60.6°C which increase 6°C than pure emulsion film. The nano-hybrid emulsion coating has a good performance, such as good acid-alkali resistance and hardness.
Abstract: In this paper, a method of carbon nanotube coated with the dendrimer encapsulated platinum nanoparticles（Pt-DENs/CNTs） was introduced, and the properties of enzyme electrode modified by the Pt-DENs/CNTs were investigated. The formation of the self-assembled (GOx/Pt-DENs)n/CNTs construction was expiored by high resolution transmission electron microscopy (HRTEM). And the results indicated that the uniform growth of the layer-by-layer nanostructures onto carboxyl-functionalized CNTs. The electrochemical properties of the enzyme anode modiﬁed by (GOx/Pt-DENs)n/CNTs, which act as biofuel cell anode, was studied by electrochemica measurements. Owing to its nanostructure, the (GOx/Pt-DENs)n/CNTs heterostructures have a large specific area, a high surface active center, good conductivity and macro tunnel effect, therefore the electrode modified by (GOx/Pt-DENs)n/CNTs has series of attractive electrochemical characteristics so as to enhance biofuel cell’s function.
Abstract: In this paper, hyperbranched organic montmorillonite (H-OMMT) with hydroxyl (-OH) groups was prepared. The organic montmorillonite (OMMT) was used as a reinforcing agent in NR matrix. The H-OMMT modified natural rubber (NR) had good mechanical properties with the addition of the H-OMMT. Properties, such as tensile strength and abrasion loss, were researched and compared. Results showed that NR/H-OMMT-5% composite had the best tensile and were resistant properties.
Abstract: Molecular dynamics simulations of the single crystal silicon nanoscale cutting with a diamond tool in ductile mode are carried out to investigate the adhesion phenomenon. After relaxation the silicon atoms on the surface reconstruct to make the potential decrease. The silicon atoms close to the diamond tool have the lowest potential (<-5.5 eV) and form a stable structure with surface atoms on the tool surface.
Abstract: Extending the investigations on (Bi0.5Na0.5)TiO3-based solid solution for lead-free piezoelectric ceramics, this paper consider the complex solid-solution system (Bi0.5Na0.5)TiO3–(Bi0.5K0.5)TiO3 [BNT-BKT]. (Bi0.5Na0.5)TiO3 with 7~ 30 mol% (Bi0.5K0.5)TiO3 ceramics have been prepared following the conventional mixed oxide process. A morphotropic phase boundary (MPB) between rhombohedral (R) and tetragonal (T) was found at the composition 0.82BNT-0.18BKT with correspondingly enhanced piezoelectric properties. The electromechanical planar coupling factor is higher for compositions near the MPB. The mechanical quality factor (Qm), planar coupling coefficient (kp) and thickness coupling coefficient (kt) of 0.82BNT-0.18BKT ceramics were 125, 28.8% and 47.4%, respectively.
Abstract: The compression behavior of open-cellular Aluminum foams was simulated using DEFORM-3D software. The structures of regular tetrahedron, octahedron and tetrakaidecahedron (Kelvin) model were developed separately. Simulation results show that the models have similar compression behavior. Then load-time curves and strain-stress curves have similar characteristics, the linear elasticity at low stresses followed by a long collapse plateau, truncated by a region of densification in which the stress rises steeply. Compared with experiment, the platform stress and the Young’ model of the Kelvin mold have good consistency within the error range.
Abstract: Based on the orientation of molecule chain in fibers, it will urge a rapid increase in mechanical properties. Nevertheless, block materials mainly gain rise of mechanical properties by blend or composite today, it is hardly proposed on self-toughening materials by optimizing the microstructure because of a lack of relations between the performance and the microstructure in block materials. In this paper, a toughening PP was gained through small deformation of spherulite, processed by uniaxial compression. A series of measurements were applied, including impact test and polarizing optical microscope (POM). The results show that the impact properties of polypropylene (PP) have a rapid rise. POM suggests that the spherulite has deformed into ellipsoid even belt along the orientation of sample of PP, which plays an important role in toughening.
Abstract: The curing, thermal and mechanical properties of bi-component system for bisphenol A epoxy resin (BPAER) modified by liquid crystalline Sulfonyl bis(4,1-phenylene)bis[4-(2,3-epoxypro pyloxy)benzoate] (p-SBPEPB), with 4,4'-diaminodiphenyl ether (DDE) as a curing agent, were investigated. The effect of the different liquid crystalline contents and the heating rate on curing reaction was discussed. The results show that the curing peak temperature decreases, curing rate increases, the glass transition temperature (Tg) and impact strength all increase with adding of liquid crystalline p-SBPEPB when the content is not over 8wt%.