Advanced Materials Research Vols. 557-559

Abstract: In this study, sawdust and polypropylene (PP) are melt-blended and injection-molded to form the wood-plastic composite (WPC).The WPC is then tested in terms of mechanical properties and compared with control groups of pure PP plate and PP/glass fiber (PP/GF) composite. In the tensile test, the WPC displays a tensile strength of 25-27 MPa, regardless of whether the sawdust content is 5, 10, or 15 wt%. Pure PP composite has a tensile strength of 30 MPa; PP/GF composite with 15 wt% glass fibers has a tensile strength of 57 MPa. In the bending test, the WPC displays a flexural strength of 44-45 MPa as the sawdust content does not influence the bending strength. PP/glass fiber composite yields a bending strength of 85 MPa when the content of glass fiber is 15 wt%. WPC is 5% lighter than PP/glass fiber composite.

Abstract: Our living environment is full of diverse electronic products, making conductive polymer a popular subject for researchers. Insulating polypropylene (PP) can be improved in terms of conductivity by intermingling with electroconductive materials. Carbon black and carbon fiber are two materials that can supplement electroconductive and mechanical properties in insulating polymer materials. In this study, natural coir is first alkali-treated and then melt-blended with PP and carbon black, forming the composite. The resulting composite is tested in terms of its electromagnetic shielding effectiveness and mechanical properties. According to the results, when the amount of carbon black is 12 wt% and coir 3 wt%, the composite displays the optimum electromagnetic shielding of -23.56 dB, tensile strength of 37.07 MPa, and flexural strength of 47.21 MPa.

Abstract: The nanocomposites composed of polypropylene (PP) and TiO₂ nanoparticles with uniform dispersion (PP/TiO₂ nanocomposite) were prepared. The effects of the content of TiO₂ nanoparticles on the crystallinity of PP and the sorption amount (M_s) of CO₂ in PP/TiO₂ nanocomposite were investigated. The crystallinity of PP increased when the content of TiO₂ was less than 2wt% and decreased Subscript text when the content was over 2wt% (M_s of CO₂ decreased when the content of TiO₂ nanoparticles was less (2 increased from 3 wt% to 5 wt%. The effects of sorption time, extended ranges of temperature and pressure on M_s of CO₂ were also studied by gravimetric method. The mechanism of the sorption and desorption of supercritical CO₂ in the PP/TiO₂ nanocomposite was discussed. In addition, the pore density of the microcellular PP/TiO₂ nanocomposite was controllable by tuning the Ms of CO₂.

Abstract: This study investigates the influence of interfacial property on the failure mode and damage mechanism of carbon fiber composites subject to shot-beam shear. Carbon fiber CCF300 made in China and T300 made in Japan were tested under the condition of 23 degree centigrade dry. Comparison was made for these composites on the shear strength data and the appearance of macro characters. Possible sequence of failure initiation and propagation of each composite was proposed by the SEM with optical microscopy observations of failed specimens. The result revealed that the interfacial property is the most important factor responsible for the failure mode of unilateralism carbon fiber composites, and the Chinese carbon fiber composites need to improve the interfacial property for wider use.

Abstract: The resistance pressure was the key to solve these problems that long rod projectiles penetrated ceramic targets at high velocity. Based on the twin shear united strength theory and the A-T model, the penetration depth were calculated. But the calculation result didn’t agree with experiment data. So the tension-compression ratio was redefined to apply to the dynamics problems according to the experiment data. And satisfied results were obtained.

Abstract: Phosphate of chrome-alumina (PCA) matrix composites were successfully prepared via thermoforming by using chrome-aluminum phosphate as adhesive, ZnO as curing agent and single component or combination of Al₂O₃, SiO₂, SiC and Si₃N₄ as fillers. We have studied the effect of different fillers on the mechanical properties, dielectric properties and moisture absorption rate of composite materials. Results show that, for the PCA-III system, when curing temperature is 180°C, the dielectric properties of materials are the best and the moisture absorption rate is the minimum; When the amount of filler is 35%, the mechanical properties of PCA-III system are the best (i.e. the tensile strength is 94.4MPa and the flexural strength is 134.7MPa).

Abstract: This paper described the preparation of optically active polyurethanes (BPUs)/multiwalled carbon nanotubes (MWCNTs) composites through the high-intensity ultrasound. SEM and TEM observations showed the homogeneous coating of MWCNTs by BPU. The infrared emissivity (8-14μm) study revealed that the composites possessed much lower infrared values compared with those of the polyurethanes and nanotubes, due to the special interface effect. The lowest infrared emissivity values of nanocomposites were S-BPU/MWCNTs εmin=0.461 and R-BPU/MWCNTs εmin=0.418, respectively.

Abstract: Based on the investigation and analysis of the causes of Dongchuan landslide, as well as on the stability analysis of Dongchuan landslide No. 1 and No. 2,it was presented by use of surface drainage, anchor pile, prestressed anchor cable lattice beam and other engineering measures on Dongchuan landslide to conduct comprehensive management. The deformations of treatment landslide were monitored and analyzed. The monitoring results show: the greatest deformation of the landslide is 8mm and the slope is a basically stable. Therefore, combined anchor piles, prestressed anchor cable lattice beam with drainage can well manage landslid

Abstract: Nanocomposites of poly(ε-caprolactone) (PCL) and layered double hydroxide (LDH) were prepared by in situ polymerization at low LDHs loadings in this work. The resultants were characterized by FTIR spectroscopy, X-ray diffraction (XRD), differential scanning calorimeter (DSC) and UV-visible spectroscopy (UV-vis). FTIR showed that the PCL/LDHs nanocomposites were prepared successfully by in situ polymerization and XRD spectra showed that the crystal structure did not change greatly in the presence of LDHS. DSC results confirmed that LDHs could act as nucleating agents. UV-vis spectra showed that LDHs had stronger absorbance peak than LDH. Moreover, the PCL/LDHs nanocomposites had strong anti-ultraviolet effect by introduction of LDHs into polymer matrix.

Abstract: Following the recent growing interest on long-lasting structures, various researches attempt to exploit Fiber Reinforced Polymer (FRP) to constructions owing to the remarkable reduction of maintenance costs brought by its outstanding resistance to corrosion. However, research dedicated to curved FRP construction material applicable to tunnel or arch bridge is still absent. This study conducts loading tests and finite element analysis in order to examine the behavior of curved FRP-concrete panel produced by pultrusion. The test results reveal that FRP and concrete exhibit linear elastic behavior until the maximum load. The parametric analysis with various FRP sections shows that the behavior of the curved FRP-concrete composite panel depends on the web height of FRP, the spacing of the webs, the length of the flange and the radius of curvature.