Search

Hybridization of filler in polymer composites is one technique of combining different properties of filler for making unique composites. Carbon nanotubes (CNTs) can be used as filler to enhance the mechanical properties of polymer composites. However, CNTs are difficult to disperse in a polymer matrix. The hybridization of CNTs and inorganic fillers can combine their properties and improve the dispersion in polymer composites. This research was focused on the fabrication and characterization of CNTs-dolomite filled with epoxy composites. The CNTs-dolomite hybrid fillers were prepared by physically mixing method and Chemical Vapor Deposition (CVD) method. The CNTs-dolomite hybrid compound filled epoxy composites with different filler loading were characterized by tensile test, Rockwell hardness test and scanning electron microscopy (SEM). The Epoxy/CVD composites showed higher mechanical properties than the Epoxy/PHY composites. This increase was associated with the homogenous dispersion of CNTs-dolomite hybrid compound as observed using SEM. It was demonstrated that the Epoxy/5CVD composites are capable of increasing tensile strength by up to 67 %, and tensile modulus of 28 %, when compared to a pure epoxy composite. [ABSTRACT FROM AUTHOR]

Platinum nanoparticle electrode modified by iodine monolayer (PtNPs/I) has been designed to simultaneously determination of Pb2+ using square wave voltammetry (SWV), the analyzed the anodic peak current and anodic maximum potential is done. The scanning electron microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDX) demonstrate some fascinating characteristics of the uniform particle distribution, growth and self-assembly of the iodine-modified platinum nanoparticle. The also examined the effect of the concentration of lead and the effect of the scan rate on anodic top parameters. The results show that the anodic current peak increases and that the anodic peak potentials increase in comparison to the clean electrode to a negative value. The have noticed that lead and scan rate increases, anodic peak current increases. As the lead concentration and scan rate increase, the anodic peak potential changes to more positive values. The easily reproducible RSD 5% (n=5) removal peak current for heavy metal ion was shown under ideal conditions. For a pre-concentration time of 120 s, the linear ranges are between 1 to 100µg. L−1. For lead ions, the concentration limit was measured as 0.408 µg. L-1 using the improved analytical process. The transmitter was a lead ion with a 0.215 µA/µM-cm2 range, with a measurement maximum of 0.01 µM. [ABSTRACT FROM AUTHOR]

Structural polymeric adhesive such as the two-part epoxy adhesive, offers many benefits in comparison to the more conventional joining methods, for instance welding and mechanical fastening. Due to epoxy's thermosetting nature, when polymerisation occur, a highly crosslinked material with superior mechanical properties will be produced. However, due to this crosslinked molecular structure they are also known to be brittle, and once crack initiated in the material, there will be no mechanism to slows down and inhibit their propagation. From the previous literatures, it was found that, rubbery second-phase inclusions can significantly increase the toughness of this thermosetting polymeric adhesive. In this study, second-phase inclusions in the form of dual-capsule self-healing system were dispersed into a commercially available epoxy adhesive to improve its mechanical properties. Tapered double cantilever beam (TDCB) specimens were used to access the Mode-I fracture toughness of the adhesive. And, it was found that, by incorporating these microcapsules an increment of as high as 80% of its baseline Mode-I fracture toughness (GIC) can be obtained. Apart from that, recovery of fracture toughness of up to 74% after full fracture can be achieved due to the self-healing characteristic of these microcapsules. Scanning electron microscopy (SEM) was used to analyse the fracture surface of the joints. The self-healing adhesives demonstrate recovery of both cohesion and adhesion properties with room temperature healing. [ABSTRACT FROM AUTHOR]

In this study, we investigated the effect of acid/alkaline-treated carbonized wood fiber (CWF) in polyethylene oxide (PEO)/Chitosan (70/30) blend film prepared by solution casting. We investigated the electrical conductivity, crystallinity percentage, crystal orientation, tensile properties, and morphology of the blend films filled with 25 wt% of untreated and acid/alkaline-treated CWF. From the results, the film filled with acid-treated CWF displayed the highest electrical conductivity when compared to the films filled with untreated and alkali-treated CWF. The x-ray diffraction (XRD) diffractograms reveal that the film filled with acid-treated CWF has the lowest crystallinity than the films filled untreated and alkaline-treated CWF. The reduction in d-spacing for the films filled treated CWF suggested improved crystal orientation for the promotion of electron transfer. The tensile properties were not affected much by the incorporation of CWF regardless of untreated or treated filler. The films with treated CWF showed slightly lower tensile strength and modulus but slightly higher elongation at break. The tensile results agree with reduced crystallinity for the blend films with both acid and alkaline treated CWF. The surface morphology of the films investigated by scanning electron microscopy (SEM) also displayed better dispersion of the conducting CWF inside the PEO/Chitosan matrix for the blends with treated CWF. The improved dispersion is due to less blockage with the presence of more amorphous regions. The presence of a broad network bridge smoothens the transfer of electrons and increases electrical conductivity. [ABSTRACT FROM AUTHOR]

Titanium dioxide (TiO2) nanoparticles based Aluminium Interdigitated Electrode (Al IDE) was tested as pH electrodes and measured quantitatively. TiO2 nanoparticle was synthesized using sol-gel method with monoethanolamine (MEA) as a catalyst. The mixing of titanium butoxide as a precursor, ethanol as a solvent and MEA as stabilizer were stirred using magnetic stirrer under ambient temperature. Al IDE were fabricated by conventional photolithography method. TiO2 solution prepared then was deposited on Al IDE using spin-coater and the coated device were annealed at 400°C. Deposition of TiO2 solution on the fabricated Al IDE forms a sensor that promising for development of TiO2 nanoparticle based biosensors. The surface morphologies structural properties were studied using Scanning Electron Microscopy (SEM). The small amount of current measurement of this device towards hydrogen and hydroxide ions was measured by Keithley 2450 pico ammeter. [ABSTRACT FROM AUTHOR]

Metakaolin is one of the mainly used materials in geopolymer due to the aluminosilicate content in it. Besides that, dolomite is also materials that have aluminosilicate content which are lower than metakaolin. Because of that, the properties of metakaolin/dolomite geopolymer were studied. The parameters used for this study are solid to liquid of 0.6, alkaline activator ratio of 2.0 and sodium hydroxide of 10M based on previous studies. The metakaolin/dolomite geopolymer were prepared by mixing the solid precursor and alkaline activator using the mechanical mixer for 5 minutes and then casted in 50×50×50cm mold. The additions of dolomite into metakaolin were done by 10%, 20% and 30% by mass. The metakaolin geopolymer with no addition of dolomite act as the control for this study. The results for 7 days show that the minor addition of dolomite into metakaolin which is 10% gave better properties with 37.36 MPa compared to others. The strength was supported by the morphology analysis by scanning electron microscopy (SEM), water absorption and density test. Morphology analysis shows the surface of lower compressive strength tends to have more pores, cracks, and unreacted materials. Other than that, increment of dolomite addition will only causes decrement of strength that is lower than the control for the geopolymer. [ABSTRACT FROM AUTHOR]

Polyethylene has wide applications as a single matrix, however it has a weakness such as low mechanical properties. Kaolin is based mineral filler that offered mechanical performance, it has been used as a cost-effective reinforcing filler for many thermoplastic materials. However, the incorporation of kaolin into thermoplastic often requires the use of compatibilizer or surface treatment to increase the mechanical performance of the composites. In this study, kaolin has been utilized as geo-filler through geopolymerization process by alkaline solution to increase the interfacial adhesion of materials in the composite. Kaolin geo-filler was found having compact structure and to improve the mechanical properties at lower filler loading. Flexural test according to ASTM D790 was performed whereas Scanning Electron Microscopy was used to observe the fracture surface. The testing and micrography are compared with the properties of raw kaolin filler on polyethylene composite. The results found that 8 % of kaolin geo-filler content is optimal for polyethylene composite and show better flexural properties. [ABSTRACT FROM AUTHOR]

Nowadays, there are various nanomaterials embedded in construction materials to improve their mechanical performances, durability, heating resistance as well as some specific properties such as self-cleaning and healing abilities. In this context, investigations regarding the effect of SiO2 nano-particles embedded in a cement matrix on mechanical properties and microstructure were performed. For this purpose nano-SiO2 powders were obtained by sol-gel method using different molar ratios of TEOS/ethanol/water. The SiO2 particles formation was confirmed by X-ray fluorescence analyses (XRF) and their nanometric sizes by scanning electron microscopy (SEM) technique. The cement based materials admixtures were obtained by using the water/binder ratio (w/b) of 0.5 and nano-SiO2 in the proportions of 0.5%, respectively 0.7 %. The distribution of nano-SiO2 particles within the cement matrix plays an essential role and governs the performance of these products. Therefore, to facilitate the nano-SiO2 particles distribution the mixtures were good homogenized in dry state. The mechanical test results showed that after 28 days of hydration the cement based materials with 0.7% nano-SiO2 content recorded better compressive strengths compared with those of the etalon (E=62MPa vs. M-NS1=72MPa). The microstructure of cement based materials highlighted the presence of Ca(OH)2, ettringite and calcium silicate hydrates as well as nano-SiO2 particles distributed into the cement matrix. [ABSTRACT FROM AUTHOR]