Suparut Narksitipan

Synthesis and Characterization of Transparent Graphene Oxide Nanosheets

Graphene oxide nanosheets have been successfully synthesized through a modified Hammers method by oxidation of pure natural graphite powder. The crystallinity, structure and morphology of the as-synthesized product were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectrophotometry, Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). XRD and FTIR were performed to verify the structure of the synthesized graphene oxide. The analysis results revealed the presence of oxygen-containing groups in the as-synthesized graphene oxide nanosheets. Additionally, SEM and TEM images revealed the graphene oxide nanosheets synthesized by exfoliation of graphite were very thin layers with transparency and similar to wrinkled and crumpled silk veils.

A Study on Influence of Zinc Oxide in Cement Composite Materials

In this research, the influence of zinc oxide (ZnO) on the phase compositions and crystalline structure and microstructure of cement composite was studied. ZnO powder (0.5-1 wt% of cement) was used as an additive material. The Portland cement and ZnO powder were blended and mixed with water at the ratio constant (W/C) of 0.4. Then, the paste was cast into the molded for 24 hours. After these periods, the samples were dried at temperature 50°C for 24 hours. Those of samples were analyzed of crystalline structure and phase compositions by using X-ray diffraction technique (XRD). Microstructure analysis by using field emission scanning electron microscopy (SEM). It was found that the XRD spectra showed phases of calcium hydroxide (CH) and calcium silicate hydrated (CS), which were hydration products of cementitious material. Moreover, phase of zinc hydroxide (Zn(OH)2) is detected. Zn(OH)2 have affected on the retardation of hydration reaction (more than 48 h). Zn(OH)2 phase was formed on the surface of anhydrous tricalcium silicate (C3S) main compound in cement. The intensity of un-hydration products (C3S and C2S) increased with increasing content of ZnO nanoparticle in cement composites.

Ferroelectric and dielectric properties of cement pozzolan –PSrZT ceramic composites with PVDF polymer as a third phase

ABSTRACT Fabrication and electrical properties of Ordinary Portland cement (OPC), fly ash (FA) and lead strontium zirconate titanate (PSrZT) ceramic composites were investigated. Ordinary Portland cement was partially replaced with fly ash at 10% by weight of binder. PSrZT ceramic of mid particle sizes (450 µm) were used at 50% by volume to produce the 0–3 connectivity composites. A third phase addition which PVDF were used 3–7% by volume. The composites were mixed and pressed together and cured with 97% RH in water bath chamber for 3 days before measurements. The dielectric properties were measured under room temperature. The ferroelectric properties and microstructure of composites were then also investigated. The results show these composites have a limited amount of PVDF of about 5.0 volume% was optimum for enhancing the dielectric and ferroelectric properties.

The Influence of Nitrogen Plasma on Crystalline Structure and Optical Properties

In this research, zinc oxide (ZnO) films were prepared by thermal evaporation method at temperature between 400-600°C for 60 min. Then, ZnO films were deposited by nitrogen cold plasma technique. The power, frequency and voltage of plasma generated at 100 W, 50 KHz and 5 KV, respectively. These films were deposited by plasma deposition for 15-60 min. The aim of this research is to study the effect of nitrogen plasma on the crystalline structure and optical properties of ZnO film. Crystalline structure, elemental compositions, morphological and optical properties were characterized by using X-ray diffraction (XRD), energy dispersive x-ray spectroscopy (EDS), scanning electron microscopy (SEM) and UV-VIS spectrophotometer, respectively. It was found that the ZnO films preparation via thermal evaporation method at temperature of 500°C showed the highest crystalline with hexagonal structure. After plasma deposition for 15, 30 and 60 min, ZnO films were amorphous. Optical transmittance values decreased and the optical band gap decreased from 3.14 to 3.06 eV with increasing in the plasma time.

Fabrication and electrical properties of PC-PNZT-PVDF-GO composites

ABSTRACT The objectives of this research are to fabricate and investigate new smart composites for the sensing and actuation applications in civil engineering. The fabrication and properties of cement-based piezoelectric ceramic composites are emphasized. However, cement-based piezoelectric composites are still difficult to obtain great electrical properties due to the evidence of some pores in the composites. Therefore, a novel approach to effectively improve their polarization of piezoelectric ceramic is to add a semiconductor (graphene oxide) and an insulator (polyvinylidene fluoride) phases between piezoelectric particles by the introduction of a small volume fraction of a third phase. Microstructure of the new composites was investigated using Scanning electron microscope (SEM). Dielectric permittivity and ferroelectric properties were then investigated.

Microstructure and Mechanical Properties of Cement/Fly Ash/Natural Rubber Composites

The physical and mechanical properties of Portland cement (PC) - natural rubber latex (NRL) - fly ash (FA) composites have been investigated. The latex per cement ratios that use in this experiment are 0, 5, 7.5 and 10% by weight of cement. Portland cement (PC) was partially replaced with fly ash 0-40% by weight of binder. Water to cement ratio were used in range of 0.305-0.385 (by weight not include water in latex). Nonionic surfactant was added in cement before mixed with natural rubber latex. In addition, to provide latex from natural rubber latex, the ammonia solution is added into natural rubber. The specimens were packing into an iron mold which sample size of 4x4x16 cm3. Moreover, the PC-NRL-FA composites were cured in water for 7 and 28 days at room temperature before measurement. Then, mechanical properties (flexural strength) and microstructure were studied.

The Influence of Aluminium Dross on Phase Compositions and Microstructure of Cement Composites

The influence of aluminium dross on the phase compositions and microstructure of cement composites were studied in this research. The cement/aluminium dross composites were prepared by adding ground granulated blast-furnace slag (GGBS) from aluminium casting industrial. The sample was added fiber optic and mixed with aluminium dross at 0.1-0.8 wt% of cement. Then, the mixture was poured into a metallic mold (5mm*5mm*5mm). After incubation with saturated lime water for 3 days, the samples were wrapped with plastic films for 7 and 28 days. The chemical compositions of raw materials were characterized by using x-ray fluorescence spectrometry (XRF). The phase compositions and crystalline structure cement/aluminium dross composites were studied by using x-ray diffraction (XRD) technique. Scanning electron microscopy (SEM) was used for characterization of microstructure of these composites.

Physical and Mechanical Properties of Cement Paste Were Used Partially with Fly Ash and Kaolin Waste

The aims of this research were study the microstructures and mechanical properties for partial replacement of cement with Fly ash (FA) and kaolin waste (KW). Ordinary Portland cement were partially replaced with FA and KW in the range of 25-35% and 10-25% by weight of cement powder. The kaolin waste was ground for 180 minutes before using. The specimen was packing into an iron mold which sample size of 5×5×5 cm3. Then, the specimens were kept at room temperature for 24 hours and were moist cured in the incubation lime water bath at age of 3 days. After that the specimens were dry cured with plastic wrap at age of 3, 7, 14 and 28 days. After that the compounds were examined by x-ray diffraction patterns (XRD) and the microstructures were examined by scanning electron microscopy (SEM). The compressive strength was then investigated.

Characterization of Cement-Rice Husk Ash Composites

In present research, the cement-rice husk ash composites were prepared and characterized. The samples were added fiber optic and rice husk ash was used as replacement cementitious materials at 10, 20, 30 and 40 wt% of portland cement. The samples were demolded after 24 h casting and cured in saturated lime water for 3 days. After these periods, the samples were wrapped with plastics films for 7 and 28 days. Then, samples were dried in air for 24 h. The chemical compositin of portland cement and rice husk ash were characterized by using x-ray fluorence spectrometry (XRF). Additionally, dried samples were analysized phase compositions and crystalline structure by using x-ray diffraction (XRD) technique. The chemical element compositions and microstructure were detected by scanning electron microscopy (SEM), respectively. Moreover, The effect of rice husk ash in these cement composites were investigated in this research.

Preparation and Characterization of Cement-TiO2 Composites

Titanium dioxide (TiO2) is the most widely used photocatalyst because of its high photocatalytic activity and reasonably low cost. Moreover, TiO2 has strong chemical stability in a large variety of environmental conditions. The combination of TiO2 with cementatious materials has been widely investigated, and the effects of the TiO2 contents (10-40% by weight) were studied in this research. The crystalline structures and chemical compositions were analyzed using x-ray diffraction (XRD) and energy dispersive x-ray spectroscopy (EDS), respectively. Moreover, its microstructure was investigated by scanning electron microscopy (SEM). It was found that the intensity of CS and CH decreased with an increase in the TiO2 powder content. This was because when adding more TiO2 powder to the composite system, more water was needed to add to the hydration reaction.