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Hollow amorphous TiO2 particles for transparent UV shielding film
(2025-05-01)
Pukveera, Nichapat
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Polpanich, Duangporn
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Wongngam, Yodsathorn
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Tangboriboonrat, Pramuan
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Suteewong, Teeraporn
Crystalline titanium dioxide (C-TiO<inf>2</inf>) particles are widely used as inorganic filters in coatings due to their high refractive indexes (n) and functions in photocatalysis. However, these particles may pose environmental and health risks due to their crystalline nature. Additionally, the long-term use of C-TiO<inf>2</inf> has the potential to damage organic contents due to their photocatalytic properties. These drawbacks make amorphous TiO<inf>2</inf> (A-TiO<inf>2</inf>) appealing for use in non-catalysis applications, e.g., coatings. This study aims to develop an alternative UV filter derived from A-TiO<inf>2</inf> with a hollow structure (HA-TiO<inf>2</inf>) that can be used in coatings. The hollow interior of the designed HA-TiO<inf>2</inf> structure compensates for its lower n through multiple light scattering, enhancing the UV shielding performance. Furthermore, the amorphous structure also promotes the transparency of the composite film. To obtain HA-TiO<inf>2</inf>, TiO<inf>2</inf>-coated silica (SiO<inf>2</inf>@TiO<inf>2</inf>) particles were synthesized using the modified sol-gel method. Selective etching was employed to remove the dense (D) SiO<inf>2</inf> core (hard template). The resulting HA-TiO<inf>2</inf> particles possessed higher UV absorption properties than D-SiO<inf>2</inf>, SiO<inf>2</inf>@TiO<inf>2</inf>, dense amorphous (DA) TiO<inf>2</inf> particles, and commercial C-TiO<inf>2</inf> (TiONA® 595, rutile). Poly(vinyl alcohol) films containing HA-TiO<inf>2</inf> particles displayed the highest UV shielding performance, effectively blocking the photodegradation of methylene blue while maintaining film transparency. The integration of high UV shielding performance of the hollow structure and transparency of the amorphous matter provided synergistic effects. Overall, HA-TiO<inf>2</inf> shows promise as a safer alternative to current inorganic UV filters in a variety of applications, including coatings, textiles, and packaging.
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Anti-corrosion performance of vinyl ester resin films with titanium dioxide and graphene hybrid reinforcement
(2022-12-01)
Khamme, Eakapoj
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Sakulkalavek, Aparporn
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Sakdanuphab, Rachsak
The present investigation addresses the development of vinyl ester resin (VER) by exfoliating titanium dioxide (TiO<inf>2</inf>) and graphene (G) in polymeric resin for anticorrosion applications on carbon steel (CS) substrates with different additive fillers (TiO<inf>2</inf> 3 wt%, G 2 wt%, and TiO<inf>2</inf> 3 wt% + G 2 wt%). The purpose of the study was to investigate structure, chemical bonding, adhesion, and corrosion. VER was prepared by triggering methyl ethyl ketone peroxide (MEKP) and an accelerator of cobalt naphthalate. The dip-coating method of VER composite films was fabricated on CS substrate with film thicknesses between 70 and 100 µm. The additive-polymer chemical bonding, morphologies and microstructure have been analysed by the techniques of Fourier transform infra-red spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Electrochemical impedance spectroscopy (EIS) and adhesion test were used to examine the anti-corrosion behaviour and performance. The blending of the additive fillers led to cobalt dispersion, crystallinity and corrosion resistance due to the development of interpenetrating polymer networks (IPNs) inside the VER films. TiO<inf>2</inf> and G hybrid reinforcements in VER enhance corrosion resistance and film adhesion.
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Optimization of Salt-Leaching Parameters for Gelatin/Na2Ti3O7 Scaffolds Using a Mixture Design Experiment
(2022-02-01)
Sangkatip, Rittichai
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Sriseubsai, Wipoo
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Kiatkittipong, Kunlanan
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Jongwuttanaruk, Kaona
The purpose of this research was to learn the formation of biomedical scaffold material from gelatin by using titanate (Na<inf>2</inf>Ti<inf>3</inf>O<inf>7</inf>), which is a newly synthesized derivative of titanium dioxide (TiO<inf>2</inf> ) with gelatin. It was prepared by mixed several solutions and cross-linked molecules by heating and salt-leaching. The biomedical scaffold was formed, and its porosity depended on the size of the salt crystal. The mixture was designed by using a mixture design with three factors: gelatin, titanate, and deionized water to determine the optimal mixture for the tensile strength of the biomedical scaffold. The microstructure of the biomedical scaffold was studied using scanning electron microscopy (SEM). The findings revealed that Na<inf>2</inf>Ti<inf>3</inf>O<inf>7</inf> thoroughly pen-extracted the biomedical scaffold, and the tensile strength of the gelatin/titanate scaffold was higher than the biomedical scaffold, which was formed using pure gelatin. By using the mixture design technique, the 14.73% gelatin, 0.2% Na<inf>2</inf>Ti<inf>3</inf>O<inf>7</inf>, and 85.07% DI water got the highest yield of tensile strength (1508.15 kP). This was an about 4.88% increase in the tensile strength property when compared with using TiO<inf>2</inf> .
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Effects of AlN on the reactive sintering of porous Al2TiO5composites
(2020-01-01)
Kitiwan, Mettaya
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Kongsak, Mongkol
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Atong, Duangduen
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Wakui, Yoshito
The porous Al2TiO5/Al2O3 composites were fabricated by reactive sintering at 1500-1700 °C in nitrogen atmosphere. The starting materials Al2O3 and TiO2 were mixed in an equimolar ratio and the addition of AlN was 5-40 mol%. The effects of AlN content and sintering temperature on phase composition, linear shrinkage, pore sized distribution, porosity and microstructure were investigated. The XRD results showed that the composites mainly consist of Al2TiO5 while the peak intensity of Al2O3 increased with AlN content. The median pore sizes decreased with increasing AlN content and were in the range of 2- 6 lm, 1-2 lm, 0.4-0.7 lm, and 0.3-0.5 lm for composites using 10, 20, 30, 40 mol% AlN, respectively. The porosities of ATN10 and ATN20 were from 20% to 10% at 1600 °C to 1700 °C while the porosities of ATN30 and ATN40 were almost constant in between 11 and 13%. The addition of AlN effectively decrease the grain size of Al2TiO5 and led to reduce microcrack at the grain boundary.
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Ultrasonically-assisted surface modified TiO2/rGO/CeO2 heterojunction photocatalysts for conversion of CO2 to methanol and ethanol
(2019-11-01)
Seeharaj, Panpailin
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Kongmun, Panyata
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Paiplod, Piyalak
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Prakobmit, Saowanee
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Sriwong, Chaval
Converting CO<inf>2</inf> to usable fuel may contribute to lowering of global warming, thus this study developed effective heterojunction photocatalysts for the photoreduction of CO<inf>2</inf> with water into methanol and ethanol fuels. The photocatalysts were prepared from combining surface modified titanium dioxide (TiO<inf>2</inf>) nanoparticles with reduced graphene oxide (rGO) and cerium oxide (CeO<inf>2</inf>). The TiO<inf>2</inf> surfaces were firstly modified via the sono-assisted exfoliation, with high intensity ultrasonic waves (ultrasonic horn, 20 kHz, 150 W/cm<sup>2</sup>) in 10 M NaOH for 1 h. Highly reactive nanosheets delaminated from outer surfaces of the primary TiO<inf>2</inf> crystals leading to an increase in specific surface active area, light absorption and decrease in electron-hole recombination rate, which enhanced photocatalytic activity. Then, 0.75 wt% rGO and 1 wt% CeO<inf>2</inf> were incorporated into the surface modified TiO<inf>2</inf> to promote photogenerated charge separation, electron mobility and CO<inf>2</inf> absorptivity. The modified TiO<inf>2</inf>/rGO/CeO<inf>2</inf> photocatalysts exhibited superior photocatalytic performance by producing methanol at 641 μmol/g<inf>cat</inf>h and ethanol at 271 μmol/g<inf>cat</inf>h, almost 7 times higher than rates from pure TiO<inf>2</inf>. The significant improvement in CO<inf>2</inf> photoconversion activity was mainly attributed to the high interfacial contact area and strong connection between the reactive delaminated TiO<inf>2</inf> nanosheets, rGO and CeO<inf>2</inf>, which, in turn, facilitated the flow of large number of photogenerated charge carriers to react with the absorbed species, and the multi-step charge transportation due to the heterojunction effect that effectively retarded electron-hole recombination.
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Electrical Bistable Properties of P-25 TiO2 Nanoparticles Composited with PVP for Memory Devices
(2019-10-01)
Ukakimaparn, P.
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Chantarawong, D.
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Songkeaw, P.
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Onlaor, K.
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Thiwawong, T.
In this work, P-25 titanium dioxide nanoparticles (TiO<inf>2</inf> NPs) were composited with poly-vinylpyrrolidone (PVP) at various concentrations of TiO<inf>2</inf> NPs. The bistable memory devices were fabricated by spin coating from a prepared PVP:TiO<inf>2</inf> NPs solution on indium tin oxide (ITO) electrodes with the device structure of ITO/PVP:TiO<inf>2</inf> NPs/Al. The maximum ON/OFF current ratio of the bistable memory devices was approximately 10<sup>5</sup> at a reading voltage of +1 V. The mechanism of the memory device can be expressed by theoretical fitting between the experimental results and conduction models. Moreover, a retention time test for continuous read operations of the device is presented.
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Optical absorption and FTIR study of cellulose/tio2hybrid composites
(2019-05-01)
Plermjai, Kittiya
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Boonyarattanakalin, Kanokthip
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Mekprasart, Wanichaya
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Phoohinkong, Weerachon
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Pavasupree, Sorapong
Cellulose/TiO<inf>2</inf> composite was prepared by conventional mixing using distilled water as medium. The structure and relevant properties of cellulose/TiO<inf>2</inf> composite were characterized by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and UV- Vis spectroscopy. XRD results exhibit typical cellulose structure type I. The absorbance spectra of TiO<inf>2</inf>and cellulose exist in vicinity of 200 nm and 350 nm in the UV range, corresponding to the UV-C, UV-B and UV-A. In addition, the UV absorption band of the composite can be extended covering wide UV region. Corresponding FTIR results suggest the existence of chemical bonding or surface interaction between TiO<inf>2</inf> and cellulose.
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Ripening control of nam dok mai mango (Mangifera indica Linn.) with titanium dioxide
(2019-01-01)
Chaishome, Jedsada
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Tunsathitsak, Yossakorn
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Boonyaritthongchai, Panida
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Supapvanich, Suriyan
— This research aims to slow down the release of ethylene of ‘Nam Dok Mai’ mango during shipment transportation by using titanium dioxide as an absorbent. The result found that the mango begin to the ripening process after stored at 13°C for 12 days (ethylene and carbon dioxide around 0.06910 µL C2H4/kg.hr and 32.10 mg CO2/kg.hr, respectively). Then, the appropriate titanium dioxide was tested by trial at 3, 5 and 10 grams. The result showed that titanium dioxide decreased ethylene but each treatment were not statistically different (p <0.05). Afterward, all fruits were stored at 13°C for 14 days and at 25°C for 4 days, respectively. The physical and chemical properties of fruit were analyzed during storage time. After 14 days at 13°C, firmness, color, titratable acidity, pH, total soluble solids and ripening index of the treatments of titanium dioxide and control treatment were significant different. After 4 days at 25°C, the ripening process of fruit between titanium dioxide treatment and control treatment were not significant differences.
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Characterization and photocatalytic activity of titanium dioxide deposited on stainless steel by pulsed-pressure MOCVD
(2018-01-01)
Wirandorn, Kornrawee
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Panyayao, Natthawut
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Siriwongrungson, Vilailuck
Titanium dioxide (TiO<inf>2</inf>) was deposited on stainless steel 304 by pulsed-pressure metalorganic chemical vapor deposition (PP-MOCVD). Titanium tetraisopropoxide (TTIP) in toluene at the concentration of 0.5 mol% was used as the precursor. The deposition was conducted at the base pressure of 300 Pa and deposition temperatures were varied between 350°C and 400°C. At these deposition temperatures, anatase phase is expected for further photocatalysis study. The deposited TiO<inf>2</inf> thin films at the thickness of hundreds nanometers were analyzed using field emission scanning electron microscopy (FESEM) for surface morphology. X-ray diffraction (XRD) was applied for phase analysis. The contact angle was measured to study its relationship with surface morphology, grain size and phase. Finally, photocatalytic activity was investigated through the absorption of methylene blue using UV/Vis spectrophotometer. The deposited TiO<inf>2</inf> thin films were found to be rutile and anatase with various surface morphology and grain size depends on the deposition temperature. The hydrophobicity of depositedTiO<inf>2</inf> thin films tend to increase with the deposition temperature whereas the photocatalytic property depends on the microstructure of TiO<inf>2</inf> thin film.
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Anatase/Rutile TiO2 composite thin films prepared via dip coating technique and their hydrophilicity, stability and photocatalytic activity
(2018-01-01)
Ibrahim, Ammar
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Phoohinkong, Weerachon
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Mekprasart, Wanichaya
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Pecharapa, Wisanu
In this work, titanium dioxide (TiO<inf>2</inf>) mixed-phase powders were prepared by sonochemical process in combination with calcination at different temperature in range of 400C to 1000C. The as-prepared powders were dispersed with tetraethyl orthosilicate (TEOS) as supported matrix of TiO<inf>2</inf> for homogeneous colloid and used as starting precursor for thin film coating. The designated thin films were deposited onto glass substrates by dip coating process. X-ray diffraction technique was employed to evaluate TiO<inf>2</inf> phase ratio meanwhile the film morphologies and hydrophilicity were investigated using scanning electron microscope and water contact angle, respectively. UV-Vis spectrophotometer was used to analyse the photcatalytic properties of the films. Photocatalytic activity of the prepared film was performed by mean of the decolorization of Rhodamine B dye solution under solar irradiation. The photocatalytic performance of assigned films was investigated and correlated mechanisms responsible for the activity are discussed.

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