Papers by Author: Chuanchom Aumnate

Abstract: The solar light consists of ultraviolet, visible and infrared ray. The ultraviolet and infrared rays, unlike visible ray, are not benefit to photosynthesis. Inorganic ultraviolet absorbing materials are mostly in crystallised phase such as TiO2, ZnO and CeO2 which caused lower transmittion in visible range. As known that, the commercial organic UV absorbers can absorb only the appointed UV wavelength. TiO2 emulsion for ultraviolet blocking was synthesized in this project in order to overcome such poor transmittion behavior. The preparative TiO2 emulsion can absorb UV completely without interfering the visible light transmittance. This is because the synthesized TiO2 via emulsion method was mainly an amorphous phase. The obtained composite film containing amorphous phase of TiO2 shows 80-90% transmittance of the visible light, 20-70% absorbance of ultraviolet A and 70-95 % absorbance of ultraviolet B.

Abstract: In this work, the effect of ethylene vinyl acetate (EVA) on the rheological and mechanical properties of low-density polyethylene (LDPE)-based greenhouse plastic films was explored. The rheological experiments showed that, for given PE and EVA, both complex viscosity and storage moduli of LDPE/EVA blends were not significantly affected when EVA content is less than 30%wt but increased with increasing EVA content thereafter. However, the mechanical results inconsistently showed that blown films with 10%wt EVA content gave the most superior mechanical properties compared to other blends. It was found that, at higher EVA contents, immiscibility between the LDPE and EVA phases occurred, resulting in much poorer mechanical performance.

Abstract: To achieve a proper dispersion of nano-particles polymer matrix and to yield a better compatibility between the nano-particles and polymeric material, the use of different coupling agents for surface modification of nano-particle is recommended. In this research, surface of TiO2 was modified by hydrolytic condensation of titanium isopropoxide with three different silane coupling agents, hexadecyl trimethoxysilane (HTMS), triethoxyvinylsilane (TEVS) and aminopropyl trimethoxysilane (APS). The grafting of silane coupling agents on the TiO2 nano-particles surface was characterized using TGA and FTIR techniques. Mechanical properties of polyethylene composite films were evaluated via tensile strength measurement. Surface morphology of the particle was studied by SEM and TEM. The result showed that surface treatment TiO2 nano-particles with TEVS could improve dispersibility of TiO2 and showed the optimum mechanical properties.