Tongsai Jamnongkan

Kinetics and mechanism of adsorptive removal of copper from aqueous solution with poly(vinyl alcohol) hydrogel

Recently, a renewed interest in techniques for heavy metal removal of wastewater has been growing because of embarking opportunities for industrial applications. We investigated the adsorption capacity of the copper on the poly (vinyl alcohol) hydrogel from the aqueous solution. Chemical structure and water absorption of the hydrogel were studied using FTIR and water uptake measurement, respectively. The results showed that the poly (vinyl alcohol) was crosslinked with glutaraldehyde, and the hydrogel highly exhibited the equilibrium swelling ratio because of its hydrophilicity property. Additionally, it was found that the adsorption process followed the pseudo-second-order kinetics and the mechanism diffusion was controlled by particle and film diffusions.

Effect of Poly(vinyl alcohol)/Chitosan Ratio on Electrospun-Nanofiber Morphologies

Series of poly (vinyl alcohol)/chitosan (PVA/CS) electrospun nanofibers with different weight ratio of PVA and CS were fabricated by electrospinning method. The surface morphology, diameter, and structure of electrospun nanofibers were investigated by scanning electron microscopy (SEM). As a result of PVA and CS composition measurements, the electrospun nanofibers morphologies were mainly affected by weight ratio of the polymer solution. When increasing the chitosan content in the blend solution, the electrospun nanofibers could hardly form. This result indicates that the electrospun nanofiber formation is enhanced by chitosan content.

Biocomposites Based on Thermoplastic Starch Reinforced with Recycled Paper Cellulose Fibers

Biocomposites sheets were prepared by compression molding from mixtures of corn starch plasticized by glycerol as matrix and cellulose fibers, extracted from used office paper, as reinforcement filler with contents ranging from 0 to 8% wt/wt of fibers to matrix. Properties of composites were determined by mechanical tensile test, differential scanning calorimetry, thermogravimetric analysis, water absorption measurement, and scanning electron microscopy. The results showed that higher fibers content raised the tensile strength and elastic modulus up to 109% and 112%, respectively, when compared to the non-reinforced thermoplastic starch (TPS). The addition of the fibers improved the thermal resistance and decreased the water absorption up to 63.6%. Scanning electron microscopy illustrated a good adhesion between matrix and fibers.

Mechanical Properties of Biocomposite Films Based on Poly(Lactic Acid) Reinforced with Cellulose Fibers

In this paper, we intended to study and improve the mechanical properties of poly (lactic acid) (PLA) composites with cellulose fibers from recycled newspapers. The influence of cellulose fiber content on tensile mechanical properties and swelling behavior of biocomposite films were investigated. In addition, the morphological property of biocomposite films was determined by scanning electron microscopy (SEM). It was found that the cellulose fibers have directly affected to the swelling behavior of biocomposite films. In addition, it was found that the cellulose fibers were found embedded between PLA matrices, which resulting to the improvement and increase the mechanical properties of biocomposite films. These findings illustrate that the cellulose fibers from recycled newspaper possesses good fillers and could be a good alternative reinforcement for biopolymer composites.

Effect of ZnO Concentration on the Diameter of Electrospun Fibers from Poly(Vinyl Alcohol) Composited with ZnO Nanoparticles

Recently, the composited nanofiber attraction has been growing from researchers across the world due to its exciting opportunities for use in biomedical applications. In this study, we fabricated electrospun fibers from poly (vinyl alcohol) (PVA) composited with Zinc Oxide (ZnO) nanoparticle for potential use in biomedical applications. From the experimental results, there was not any chemical bonding between the ZnO nanoparticles and the PVA molecules. The effect of concentration of ZnO nanoparticles in PVA solution on the diameter of electrospun fibers was found that the diameter of electrospun fibers increased with raising the concentration of suspended ZnO nanoparticles in solution. This is probably because the effect of nanoparticles on the diameter of electrospun fibers was through their effect on the viscosity of solution. In addition, we found that the diameter of electrospun fibers depended on the solution and processing parameters.

Comparison the Physical and Antimicrobial Properties of Poly(Lactic Acid) Film and its Composites with ZnO Nanoparticles

Polylactic acid (PLA) is a bioplastic, which is produced from natural materials. It is well known that the PLA can be degraded in the environment which is alternatively rendered to replace the plastic from a petroleum base. In this paper, we study the physical properties of composite films prepared from PLA composited with zinc oxide nanoparticles (ZnO NPs) by using solvent casting technique. It was found that the ZnO NPs have affected to the morphological, water absorbency, mechanical and antibacterial properties of biocomposite films. In addition, we also found that the particles of ZnO NPs can disperse within the PLA matrices, which enhanced the stress and Young’s modulus of biocomposite films. Additionally, the result shown that the PLA/ZnO NPs films exhibit good antibacterial activity both in Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacterial strains.

Preparation of Pure Anatase TiO2 Thin Films by DC Sputtering Technique: Study on the Effect of Oxygen Partial Pressure

Titanium dioxide thin films were deposited by DC reactive magnetron sputtering on silicon wafer and glass slide at sputtering power of 210 watt under total pressure of 5.0×10-3 mbar at different oxygen partial pressure. A pure metallic titanium target was sputtered in a mixture of argon and oxygen gases. The crystal structure and surface morphology were characterized by X-ray diffraction (XRD) and atomic force microscopy (AFM), respectively. The optical transmission was measured by spectrophotometer. The results show that the crystalline was pure anatase structure titanium dioxide thin films. The surface morphology of the films is strongly the oxygen partial pressure. It was found that surface roughness of the thin films was around 2.42 to 4.82 nm and the thickness was around 72 to130 nm. In addition, it was found that all the titanium dioxide thin films were deposited by reactive sputtering with the different oxygen pressure exhibit the transparency property.