Advanced Materials Research Vols. 332-334

Abstract: Gelatin is a kind of biopolymer obtained from animals and its fiber has been used as one of biocompatible dressings and sealants for many years. Electrospun gelatin nanofiber got more attention for its high specific surface area. Low toxicity gelatin nanofiber mats can be obtained by using water as the solvent in electrospinning process, but the fiber diameter below 150 nm is not easy to control and lots of beads were formed in the mats for low concentration solutions. In this study, sodium dodecyl sulfate (SDS) and ethanol were used to improve the electrospinnability of the gelatin solution with the concentration of 13 wt %. Experimental result revealed that SDS and ethanol reduced the surface tension of gelatin solution, meanwhile increased the conductivity and the viscosity. With the ratio between water and ethanol of 95 to 5, and SDS content varied from 0.3 wt % to 0.8 wt %, beads along the gelatin fibers vanished. Smooth and uniform gelatin fibers with fibers’ diameter around 110 nm were obtained.

Abstract: According to theoretical consideration of metallurgists’ protective clothes reliability increase problem all the major questions, connected with obtaining of new kinds of composite materials and their properties regulated by special requirements, were experimentally studied. There is suggested a formation of new fireproofed fabrics, which have high protective properties to the melted drops of metal, injuring the special cloth of the metallurgist.

Abstract: A series of N-octadecylated polyethyleneimine (PEI18C) comblike polymers with different grafting ratios, through N-alkylation method, have been successfully prepared. The chemical structure and thermal behavior of PEI18C comblike polymers with different grafting ratios has been characterized by Fourier transformed infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). Experimental shows that C18 alkyl groups have been successfully grafted onto PEI backbones, and the thermal behavior of PEI18C comblike polymers with different grafting ratios exhibit the linear increment with the grafting ratio of alkyl groups. It can be attributed to the effect of the grafting density of alkyl side groups along PEI backbones. The detailed investigation and discussion is carried out from the viewpoint of side chain crystallization and molecular packing behaviors.

Abstract: A series of novel miktoarm star polymers were synthesized by combination of at-om transfer radical polymerization(ATRP), chemical modification and ring-opening polymeri-zation(ROP). These miktoarm star polymers carring one poly[6-(4-methoxy-4’-oxy-azobenzene) hexylmethacrylate] azobenzene (PMMAZO) side-chain liquid crystalline(LC) arm and two polycaprolactone(PCL) arms. These precursors and miktoarm star polymers were characterized by proton nuclear resonance (1H-NMR), and gel permeation chramatograph(GPC). The information of PMMAZO(OH)2 and PMMAZO-(PCL)2 miktoarm star polymer confirmed the expected structure.

Abstract: The linked-pearl pattern on fabric is a key to study on the transformation of the technique from weaving warp-faced patterns to weft-faced patterns in ancient China. However, the previous studies on the linked-pearl pattern on fabric were not very clear, and led to much misunderstanding. Some researchers believed that Chinese weavers did not master the technique of weft-faced patterns until Persian merchants introduced the brocades with a pattern featuring stringed ball into China along the Silk Road. Based on the studies on historical materials and archeological discoveries of the linked-pearl pattern on fabric, we hold that there are positive connections among the linked-pearl pattern, the technique of weaving weft-faced patterns and the draw loom. The dissemination of the linked-pearl pattern prompted the development of pattern design and the wide application of weft-faced pattern on fabric, even the invention of the draw loom which accelerated the development of textile technology in ancient China.

Abstract: A new polishing head is studied in magnetic-electrochemical compound polishing in the paper. Added a magnetic field whose direction is parrallel to the electrical field’s directions, the charged partcles between two electrodes can move in spirals in magnetic-electrochemical compound polishing, and then the condition of chemical reaction is improved. If the direction of magnetic field is changed alternative, the effect of polishing can be improved more clearly. The tool can be fixed on spindle of CNC easily. The tool is flexible, so it can make the polishing head and workpiece touch evenly each other. Because the head of magnetic-electrochemical compoud polishing tool is a series, the head can be replaced conveniently according to different surface. Particularly,the tool can change strength of the magnetic field easily. At last, the tool is tested and its function is perfect.

Abstract: This paper describes an experiment of Corn starch treatment with α-amylase under the condition of supercritical CO2 at 50°C, 11MPa, and investigates the effects of different water content on supercritical CO2 treatment of corn starch. The results demonstrate that the viscosity of the treated starch is much lower than that of untreated starch, as well as the variance ratio of the viscosity is up to 96%. The optimum water content for the degradation of the enzymatic reaction is 2%;when water content is up to 3%, the viscosity of the serosity is 5Mpa•s, and the sizing performance reaches the best.

Abstract: In this paper, with the ANSYS, stress distribution and safety factor of crankshaft were analyzed by using 3D finite element method. The results show that the exposed destructive position is the crankpin and the transition circular bead location of main journal. Maximum stress is 156 MPa. Safety factor is 3.22. Maximum deformation is 0.462 mm. Crankshaft satisfies the design requirement.

Abstract: Gold nanoparticles dispersions were prepared by hyperbranched polyamide (HB-PA) in aqueous solution without additional reducing agents. The prepared gold nanoparticles/polymer composites were characterized by UV-visible spectrophotometer, TEM and HPPS. The size of the synthesized gold nanoparticles decreases with the increase of the molar ratio of nitrogen in HB-PA to Au atoms. EDS, XRD as well as XPS were further employed to verify these particles were indeed metallic gold nanoparticles and FT-IR analysis showed the interaction between gold nanoparticles and polymers. These techniques indicated the tunability of the size of gold nanoparticles by HB-PA which can also serves as a layer of protection for them.

Abstract: The draping and buckling of woven fabric are simulated with the finite element method based on the micro-mechanical constitutive model and orthotropic constitutive model under gravity load. Compared with the traditional orthotropic mechanical model of the fabric, the micro-mechanical constitutive model characterizes the special properties of woven fabric due to its micro-weaving structures. The woven fabric sheet is discretized with 8-nodes shell elements which are designed for finite deformation and suffice to describe the large rotation of fabric sheet during draping, for the sake of simplicity, the nodes of the fabric sheet on the edges of the desk are assumed to be fixed. Compared with the experimental ones, the simulation results with the micro-mechanical constitutive model are in good agreement with the observations. The work paves the way for developing a virtual clothes trial system.