Pattana Rakkwamsuk

Effects of Coir Fiber and Maleic Anhydride Modification on the Properties of Thermoplastic Starch/PLA Composite Laminates

Coir fiber reinforced composite laminates made of poly(lactic acid) (PLA) with a thermoplastic starch (TPS) were fabricated. Modified thermoplastic starch (MTPS) was prepared by reactive blending of TPS with maleic anhydride (MA). The effect of coir fibers was of our main interest. The tensile properties, water absorption, and morphological properties of the fabricated composite laminates were investigated. The composite laminates between PLA and starch TPS were prepared using coir fiber as reinforcing core, and the physical, mechanical, and morphological properties were studied. The results suggested that the optimum fiber contents for maximum tensile strength for TPS/PLA and MTPS/PLA composites were 20 and 30 wt%, respectively. Using MA for chemical modification of TPS for PLA composites could reduce the PLA content of about 10 wt%, and improve the tensile about 20%. The volume swelling for the MTPS/PLA composites was much lower than that for the TPS/PLA composites, and the swelling reduced with increasing coir fiber content. Based on compressive strength, the pallets produced using MTPS/PLA composites showed a high potential to replace the commercial urea-formaldehyde/PLA composites. It clearly appeared that MA modification to TPS not only improve the mechanical properties of fiber reinforced PLA composites, but also made the PLA composites bio-degrade more quickly.

Preparation of IR Reflective Green Pigment

This research article reports a development on green pigments having high reflectance of NIR radiation from the sun. The aim of the development is to use the green pigments as a component of building paint to reduce heat penetrating into the building. Cr2O3, a green pigment oxide, was used as the host component and the mixtures of Al2O3, V2O5 and TiO2 were used as the guest components. Al2O3, V2O5 and TiO2 were mixed at different 36 compositions according to triaxial diagram. For each sample preparation, 80% wt Cr2O3 was mixed with 20%wt of guest component for each composition. Then the mixed sample were calcined at 1150 °C for 4 hours and were ground with an agate ball mill for 7 minutes at a speed of 250 rev/min. Finally, the pigments were sieved to obtain the particle sizes of 0.5 - 2.0 µm. The pigment powders were compressed in a mold to get samples in the form of thin disks, each one with a diameter of 2.7 cm and a thickness of 4 mm. The reflectance for all samples was measured using a spectrophotometer in the wavelength ranging from 300 – 2100 nm in accordance with ASTM E891. It was found that the maximum reflectance, in the wavelengths ranging from 780 – 2100 nm, of 82.83% was obtained from the sample with a composition of 80%Cr2O3, 14%Al2O3, 4%TiO2 and 2% V2O5.

INFLUENCE OF CONTINUOUS AND DISCONTINUOUS DEPOSITIONS ON PROPERTIES OF ITO FILMS PREPARED BY DC MAGNETRON SPUTTERING

Indium tin oxide (ITO) films were deposited on glass substrate without external heating by DC magnetron sputtering with continuous deposition of 800 s (S1) and discontinuous depositions of 400 s × 2 times (S2), 200 s × 4 times (S3) and 100 s × 8 times (S4). The structural, surface morphology, optical transmittance and electrical resistivity of ITO films were measured by X-ray diffraction, atomic force microscope, spectrophotometer and four-point probe, respectively. The deposition process of the S1 condition shows the highest target voltage due to more target poisoning occurrence. The substrate temperature of the S1 condition increases with the saturation curve of the RC charging circuit while other conditions increase and decrease due to deposition steps as DC power turns on and off. Target voltage and substrate temperature of ITO films decrease when changing the deposition conditions from S1 to S2, S3 and S4, respectively. The preferential orientation of ITO films were changed from dominate (222) plane to (400) plane with the increasing number of deposition steps. The ITO film for the S4 condition shows the lowest electrical resistivity of 1.44 × 10-3 Ω·cm with the highest energy gap of 4.09 eV and the highest surface roughness of 3.43 nm. These results were discussed from the point of different oxygen occurring on the surface ITO target between the sputtering processes which affected the properties of ITO films.

Characterization of Anatase and Rutile TiO2 Thin Films Deposited by Two Cathodes Sputtering System

Titanium dioxide, TiO2, thin films were deposited on unheated Si (100) wafers by two cathodes sputtering system. However, during the deposition of TiO2 films only one cathode was used. A pure metallic titanium was used as a sputtering target. Argon and oxygen were used as sputtered gas and reactive gas, respectively. TiO2 films were deposited at the argon and oxygen ratio of 1:4 and a total pressure of 5.0 x 10-3 mbar. The distance between the target and the center point of substrate was 12 cm. For each deposition of TiO2 films, the position of substrate was changed every 2 cm on the radial position of the cathode. The deposition time for each deposition was 60 min. The films were characterized by X-ray diffraction (XRD) technique and transmission electron microscopy (TEM). The XRD results and TEM images show that the crystalline rutile TiO2 films can be successfully deposited on an unheated substrate.

Influence of Structural and Electrical Properties of ITO Films on Electrochromic Properties of WO3 Films

Indium tin oxide (ITO) films had been deposited on glass substrate without substrate heating and then tungsten oxide (WO3) films were deposited on ITO films by DC magnetron sputtering. In this work, we present the annealing ambient effect of ITO substrate on electrochromic properties of WO3 films. The ITO films were annealing in air and in vacuum at 350°C before coating with WO3 films. The structural, optical, and electrical properties of ITO films for as-deposited, annealing in air and in vacuum were investigated by X-ray diffraction, UV-VIS-NIR spectroscope and four point probe. The ITO films had a better crystallinity and lager grain size after annealing in air and in vacuum. The resistivity of ITO films increase with annealing in air, but decrease with annealing in vacuum. The WO3 films show difference surface morphology with higher grain size and surface roughness when coating on annealed ITO films in both cases. The electrochemical properties of film systems were characterized by cyclic voltammetry. The film systems of ITO plus WO3 showed that the charge capacity of ITO substrate annealing in vacuum was higher than the as-deposited ITO substrate and the ITO substrate annealing in air, respectively. This result corresponded to electrical conductivity of each ITO substrate.

Towards Cooler Buildings: The Case of Thailand

One of the most important tasks facing hot-climate cities is cooling. The objective of the ELITH research program (Energy and Low-Income Tropical Housing, ELITH webpage, http://www2.warwick.ac.uk/fac/sci/eng/elith/about/, 2013–2016) in which the editors of this book took part, was to reduce energy use and climate emissions in the built environment. With a particular focus on low-income housing in hot-climate developing countries, this included issues of sustainable design and city planning as well as energy systems and policy. In the area of policy, a key action, in all countries, is to develop standards, codes and building regulations for energy efficiency (and/or carbon emissions; both approaches may be adopted). This was addressed for the case of Thailand where our ELITH partner was the Joint Graduate School of Energy and Environment (JGSEE) in Bangkok (JGSEE webpage, http://www.jgsee.kmutt.ac.th, 2016). This chapter describes processes, methods and challenges involved in introducing and implementing energy-efficiency policies in national building regulations and practice. After describing very briefly the context of Thailand, its buildings, energy use, trends, institutions and existing or recent initiatives in energy efficiency, we review the JGSEE research. The role of local organisations and institutions is highlighted. In the last section, we discuss broader issues and the relevance of these experiences for other countries.

Effect of Annealing Ambient on Self-Cleaning Properties of TiO2 Films Prepared by Reactive DC Magnetron Sputtering

Titanium dioxide (TiO2) films were prepared on glass substrates without external heating by DC magnetron reactive sputtering. Argon and oxygen were used as sputtering and reactive gases, respectively. Initially TiO2 films were produced under a constant discharge power of 300W, total operated pressure of 1.10 Pa, the Ar:O2 flow rate of 50:45 sccm and film thickness of 300 nm. After deposition, the films were annealed in air and in vacuum (8×10-1 Pa) at a temperature of 350 °C and an annealed time of 2 hours. Films structure, optical properties, photocatalytic activity (methylene blue degradation) and photo-induced hydrophilicity properties were mainly investigated to produce self-cleaning surface. Because of higher crystallinity of vacuum-annealed films lead to the highest MB degradation under UV irradiation. While, air-annealed films showed lower MB degradation than as-deposited films that could be affected of contamination on surface and defect from annealing. Vacuum-annealed films showed changes of water contact angle on the films surface higher than as-deposited films and air annealed- films.

Self-Cleaning Properties of TiO2 Films Deposited by Reactive Magnetron Sputtering Using Smooth D.C. and Pulsed D.C. Source

he TiO2 films were prepared by reactive smooth d.c. and pulsed d.c. magnetron sputtering on glass slide substrates. A metallic titanium target was reactively sputtered in a mixture of argon and oxygen. The influence of smooth d.c. and pulsed d.c. discharge power on films thickness, crystallinity, surface morphology, photocatalytic activity (methylene blue degradation) and hydrophilic activity were studied. At pulsed d.c. sputtering, plasma generator has been used to provide the asymmetric pulsed d.c. bias of the target at 100 kHz and pulsed off-time 4016ns. The structures of the films at 100nm and 300nm thick showed nano-grain size structure. The pulsed d.c. mode deposition exhibited a considerably lower surface roughness, but higher grain size compared to the films deposited with the smooth d.c. mode. At film thickness about 300 nm, the XRD peaks indicated that the dominant structure was anatase for which the preferred orientation was in (101) plane. It did not show any definite change of phase between the films deposited in the smooth d.c. mode and the film deposited in the pulse d.c. mode. For the photocatalytic activity, it was clearly seen that the films deposited by smooth d.c. mode showed a higher photocatalytic activity. The hydrophilic activity test, after the films had been irradiated by an ultraviolet light source for 30 min., the smooth d.c. mode films (thickness 300 nm) showed that a water contact angle can be less than 10°. In this study, the TiO2 films of smooth d.c. mode sputtering could be applied for a self-cleaning glass application.