Advanced Materials Research Vol. 664

Abstract: In this study, natural rubber (NR) nanocomposites containing different loadings of multi- walled carbon nanotubes (CNTs) (0.1-0.4 phr) were prepared by latex compounding. The as-prepared nanolatex composites were cast into 3-mm sheets on a glass mold and then cured at 80°C for 3 h. The obtained vulcanizates were evaluated for their mechanical properties (tensile properties, tear strength and hardness) and surface electrical resistivity. The results showed that the incorporation of CNTs at a very low loading can reinforce NR by enhancing the tensile strength (0.2 phr optimal), modulus at 300% strain (0.2 phr optimal), elongation at break (0.4 phr optimal), tear strength (0.4 phr optimal) and hardness (0.4 phr optimal) and also increase the electrical conductivity (0.2 phr optimal). The reinforcing effect of CNTs is primarily attributed to its very high aspect ratio and great specific surface area, whilst the electrical conductivity of the nanocomposites is due to the formation of a continuous conductive network of CNTs in the NR matrix.

Abstract: Quasioptical reflectometer based on hollow dielectric beamguide (HDB), terahertz beamguide components and elements has been developed. The reflectometer has been analyzed in terms of its application for nondestructive method for surface and subsurface contamination of carbon fiber reinforced plastic (CFRP). Sub-terahertz (0.1…0.2 THz) measurement results of CFRP samples with different surface contaminations are presented.

Abstract: Carbon dioxide (CO₂) laser was applied to fabricate TiC reinforced composite coatings. Different microstructures of ceramic phases were observed by SEM. The main phases of coatings were detected by XRD, while the individual one was examined by electron probe X-ray microanalysis .The effect of composition of binder phases on morphology was explained by the ratio of the temperature gradient in front of the liquid/ solid interface to the growth rate.

Abstract: Three novel kinds of support film, including PVDF-PAA film, PVDF·TiO₂–PAA film and PVDF–g–AA film, were synthesized and used to immobilize the Pd/Fe bimetallic nanoparticles (NPs). The immobilized Pd/Fe bimetallic NPs systems were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, contact angle analysis, and X-ray photoelectron spectroscopy. The dechlorination efficiency of the immobilized bimetallic NPs systems were tested and discussed by dechlorinating monochloroacetic acid (MCAA). Comparing with free suspended Pd/Fe NPs, bimetallic NPs with support films appeared better catalytic dechlorination efficiency, and the dechlorination efficiencies of 10 mg/L MCAA in 120 min by Pd/Fe NPs immobilized in PVDF–PAA film, PVDF·TiO2–PAA film and PVDF–g–AA film were 56.33%, 71.01% and 75.51%, respectively.

Abstract: PVDF membrane was modified by hydrophilization method, Pd/Fe nanoparticles were successful immobilized in hydrophilized PVDF membrane as catalytic reduant to dechlorinate monochloroacetic acid, the Pd/Fe nanoparticles characterized by Scanning Electron Microscopy (SEM). The hydrophilized PVDF membrane was characterized by Fourier Transform Infrared Spectroscopy (FT-IR). The PVDF membrane immobilized Pd/Fe nanoparticles (NPs) as caralytic reducant was used to dechlorinate monochloroacetic acid (MCAA), the monochloracetic acid dechlorination efficiency was high.

Abstract: Silver film was fabricated on a glass substrate by electroless plating technique. Plating solution, which also known as Tollen’s reagent, consisted of three main solutions: silver nitrate solution as a silver source, ammonia and sodium hydroxide as pH controllers and D-glucose as a reducing agent. Glass surface was treated by three different methods: HF etching, SnCl₂ activation and SiC paper grinding. After that, a glass slide was immersed in plating solution for 90 minutes at a room temperature. The purpose of this work was to study the effects of different surface treatments on adhesion between substrate and film. X-ray diffraction (XRD) pattern confirmed that the obtained film was a silver phase. Surface morphology of glass slides, before and after plating was investigated by scanning electron microscope (SEM). Moreover, the adhesion of silver film to glass substrate was performed by crosscut test and it was indicated that combined treatment by SiC paper grinding and HF etching was the best surface treatment which provided a good adhesion of film to substrate.

Abstract: Non-contacting (rattle-type) carbon-sphere@TiO₂/Cu core-shell composites were prepared through the spray drying technique combined with calcinations using melamine formaldehyde (MF) microspheres as core templates, and TiO₂ colloid and cupric salt as shell precursors. After the calcination of the as-dried MF@TiO₂/cupric salt core-shell spheres at elevated temperatures under nitrogen, rattle-type carbon-sphere@TiO₂/Cu core-shell composites were derived with relative uniform sizes. Photocatalytic tests showed that the composites obtained at 550 °C exhibited higher efficiency than those obtained at 700 and 800°C and also higher than the P25 commercial TiO₂ for the degradation of methylene blue (MB) under visible light irradiation. Antibacterial studies revealed that the rattle-type composites owned excellent antibacterial ability and were stable and reusable.

Abstract: The microstructure and properties of plasma arc welding (PAW) with depth penetration keyhole SAF 2205 duplex stainless steel were examined. High-quality, full-penetration welds were successfully produced in the duplex stainless steel by plasma arc welding (PAW) with depth penetration keyhole. The base material had a microstructure consisting of the ferrite matrix with austenite islands. Ferrite content was held between 60 and 70% throughout the weld. The number grain of the ferrite and austenite phases caused increase in hardness and strength within the stir zone. In the evaluation experiment was used metallographic observation of the integrity and structure of the recast, measuring the proportion of austenite-ferrite in recast, hardness measurements.

Abstract: Nowadays, composite material is more and more popular mainly because of its low density and high strength. This paper focuses on experimental research of coarse milling process of carbon fiber reinforced carbon matrix composite (C/C composite) in low spindle speed and large milling depth. The milling force prediction model for milling of composite using the end milling cutter is built by orthogonal experiment. Experiment test shows that the results predicted by the proposed model are in well agreement with measured ones and the milling force increases with the increment of feed per tooth, milling depth and milling width, and the effect of milling speed on milling force is not very obvious. In addition, machining accuracy and quality of machined surface is difficult to satisfactory, because of the existence of the substrate lacunas and carbon fibers in C/C composite, by using the existing ordinary material surface integrity evaluation method.

Abstract: Thermal degradation of polyene synthesized from recycle polyvinyl chloride (PVC) and hardness of polyene coated with modified oil has been studied by thermogravimetric analysis (TGA) and microhardness test. The synthesized polyene from reaction of recycle PVC were varied from 30 minutes, 1 hour, 2 hours and 4 hours and their thermal stability has been analyzed. From differential thermal gravimetric, DTG curve, polyene from two hours reaction showed the highest degradation temperature up to 445°C due to degradation of polyene sequences. Microhardness test performed by Shimadzu DUH 211/DUH-211S dynamic ultra microhardness tester according to ASTM E384 showed that polyene derived from 2 hours PVC with modifed oil resin resulted in the highest microhardness ~ 107.99 MPa.