Advanced Materials Research Vols. 150-151

Abstract: MoSx/Au films about 1μm in thickness were deposited on 9Cr18 steel substrate discs by magnetron sputtering method. The chemical composition and chemical states of the as-deposited films were determined by X-ray photoelectron spectroscopy (XPS). The effect of high loads (15~50N) on tribological behaviors of the MoSx/Au films in vacuum was studied by pin-disc wear tests. The pins were made of 2Cr13 steel. The morphologies of as-deposited films and wear track were observed by scanning electron microscopy (SEM). The results show the friction coefficient and the wear life of the films decrease with the increase of load at a sliding velocity of 1.6 m•s-1. The wear life of the films at 15N can reach 2000m. The friction process of the films can be divided into four stages based on typical variation of friction coefficient with sliding time in vacuum, e.g. running-in stage, steady stage, severe damage stage and thorough wear stage. In steady stage, the films peel in small pieces and the abrasion mechanism appears delamination wear. When the film was damaged thoroughly, the wear test carried out between 2Cr13 pin/9Cr18 disc. The adhesive wear becomes the dominant abrasion mechanism.

Abstract: A novel Tin-functionalized integrated rubber of styrene-isoprene-butadiene tri-copolymer (SIBR) was prepared in the styrene (St)/isoprene (Ip) /butadiene (Bd) system with self-made tin-containing organolithium (simplified as SnLi) as initiator via living anionic polymerization. By means of several measures such as TEM, SEM and dynamic viscoelastometer, morphology, static mechanical properties, wear ability, dynamic heat build-up and dynamic viscoelasticity of Tin-functionalized SIBR (Sn-SIBR) were studied and compared with non-functionalized SIBR and NR/S-SBR (40/60) blend. The result shows that with improving antiskid properties and wear resistance, Sn-SIBR reduces the rolling resistance over 30%, which has excellent mechanic properties and dynamic properties. Sn-SIBR satisfies the overall property requirements of high-performance tire tread, and it is an ideal new style tread material for high-property environmental green tire.

Abstract: The performance of Capillary Crystalline Waterproofing Coatings(CCWC) was measured by its impermeability and self-healing ability. At the meantime, the microstructure of mortar treated by CCWC was researched with SEM and XRD. The results showed that Ionic transmission could cause a chemical reaction, generate a great quantity hydrate products to block up the pores and cracks in cement-based materials, endow it with self- healing ability, and increase its durability. With increment of the coverage rate, pores and cracks of cement-based materials can be better healed with ionic transmission.

Abstract: Using corundum, quartz, kaoline, etc, as base components and CeO2-rich mixed rare earth as modifier, foam ceramics were fabricated adopting the organic foam impregnation process. The mixed rare earth addition had much improving effects on the matrix mechanical properties owing to much glass phase and acerate mullite growing. While 3wt% was considered to be the optimal addition, in this case, homogeneous and compact ceramic microstructure with maximal glass condensation and minimal porosity formed, with the matrix compressive strength and the flexural strength at room temperature reached 0.87MPa and 0.66MPa respectively, which were 52.6% and 73.7% higher than the original samples respectively. As the mixed rare earth addition exceeded further, the compressive strength increased slowly and the flexural strength descended gradually. XRD and SEM were used to structure strengthening mechanism analysis.

Abstract: The UV-curable unsaturated polyester (UPR) was modified with glycidyl methacrylate and methylacryloylpropyl polyhedral oligomeric silsesquioxanes (MAP-POSS), and the cure kinetics of MAP-POSS/UPR system was investigated by non-isothermal DSC. The result shows that UPR, glycidyl methacrylate and MAP-POSS have very good compatibility and can co-cure in free radical polymerization.The curing reaction can be described by a two-parameter autocatalytic Šesták-Berggren (S-B) model. The average reaction activation energy Ea for 6% and 9% MAP-POSS content is 73 kJ/mol and is lower than 0% ( about 82kJ/mol). The mechanical loss peak temperature Tp of curing nanocomposites increase with increasing MAP-POSS content and has a highest value when MAP-POSS content is 9%, which is 114.1 oC and higher about 12 oC than pure UPR.

Abstract: The concrete microstructure can affect its macroscopic properties, such as the strength and durability, etc. Based on the experimental study of cube compressive strength of steel fibre reinforced concrete, splitting tensile strength, flexural strength, and using by mercury intrusion method to test the pore structure of steel fibrous, this paper analyzes the influence of fibre on concrete pore structure. And then on mechanical properties of concrete from microcosmic perspective.

Abstract: Wood/Polyethylene (PE) composites were modified by air glow discharge plasma. The modified composites surface were characterized by contact angle measurements, attenuated total reflection-fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). The results showed that the surface wettability was improved, -OH, C-O and C=O bond were introduced on the surface, the oxygen element content increased and the shear bonding strength increased after plasma treatment. However, in the period of aging, the modified surface was unstable and exhibited a hydrophobic recovery, meanwhile the oxygen-containing functional groups reduced, O/C ratio increased and the shear bonding strength decreased gradually.

Abstract: Poly(ethylene-octene)(POE) and organic montmorillonite(OMMT) acting respectively as the toughening agents and reinforcing agents, were used to prepare nanocomposites with Poly(trimethylene terephthalate)(PTT) in order to modify PTT, and the rheological properties of these composites were investigated by using capillary rheometer instrument. The OMMT used in composite was prepared by intercalating triphenyl phosphate (TPP) into MMT by mixed solution method. PTT/POE/OMMT nanocomposites were prepared by melt blending in twin-screw corotating extruder. Rheological results show that PTT/POE/OMMT composite melt was pseudo-plastic liquid and the pseudo-plasticity of the melt was decreased with increasing OMMT content for the strong interface interactions between OMMT and polymer molecular chains. The melt apparent viscosity was increased with increasing OMMT content. The flow activation energy results suggested that the composite melt having more OMMT components is more sensitive to the change of temperature.

Abstract: The morphological, mechanical and rheological properties of poly(trimethylene terephthalate)(PTT)/maleinized acrylonitrile-butadiene-styrene (ABS-g-MAH)/short carbon fiber (SCF) composites were investigated by the scanning electron microscopy(SEM), universal tester, impact tester and capillary rheometer, respectively. The SEM images of the composites’ fracture surface show that the fracture surface is rough and SCF are randomly dispersed in the matrix resin, and there is a good interfacial interaction between SCF and PTT. The composites show the maximum tensile strength when adding 10-23% SCF into PTT/ABS blends. The rheology results show that the composites melt are pseudo-plastic fluid, and the melt apparent viscosity of the PTT/ABS/SCF composites increases with increasing SCF content.

Abstract: This paper presents the results of an experimental research work designed to study the flexural strengthening capacity and the modes of failure of Reinforced Concrete (RC) rectangular beams which are strengthened with external bonding of carbon fiber reinforced polymer (CFRP) composite materials to the tensile face of the RC beams. In total, seven beams were cast, one beam was preserved as control beam, two beams were strengthened without the application of preloading and the four beams were precracked and repaired with CFRP sheets. The main experimental parameters include the original damaged degree of RC beams, the amount of CFRP sheets, the longitudinal tensile reinforcement ratio, shear span to effective depth ratio, and the concrete cover thickness. All beams were tested in four-point bending over a span of 1500mm. Test results in the current study indicate that the effectiveness and flexural capacity of the CFRP strengthened beams. The flexure enhancement of the CFRP strengthened beams varied between 41% and 125% over the control beam. This study confirms that the CFRP sheets technique significantly enhances the flexural capacity of reinforced concrete beams. Finally, the contribution of CFRP sheets on the flexural capacity and rigidity of precracked and non-precracked RC beams is significant for the more longitudinal tensile reinforcement ratio.