Distribution Of TiO2 Particles Research Articles

Germ-Reducing Titanium Dioxide - Silicone Rubber Composites

Germs are present in all areas of everyday life and can lead to dangerous infections. Surfaces with antimicrobial properties are used to reduce the risk of infection in sanitary facilities and hospitals. Apart from the addition of biocides or antibiotic agents to synthetic materials, research shows that it is possible to use the semiconductor titanium dioxide (TiO2) to generate antibacterial surfaces. Photocatalytically active TiO2 leads to the development of reactive oxygen species (ROS) that are able to kill germs. The aim of this research is to use TiO2 to generate antibacterial bulk material. Nanostructured TiO2 particles were incorporated into silicone rubber to obtain a photocatalytic active polymer surface. High temperature vulcanizing (HTV) silicone rubber was used as a matrix material, and samples with 10 wt% of TiO2 were produced. The distribution of TiO2 particles in the matrix was analyzed via light microscopy. The photocatalytic activity on the surface of the test samples was studied via microbial testing with E.coli bacteria. The samples showed different intensities of the photocatalytic effect depending on the type of additive. The effort to create a germ reducing silicone rubber surface by using TiO2 as an additive was successful.

Photocatalytic TiO2 Embedded on PET-g-PAAc Fabric by Sono-gamma Irradiation Technique

Fabrication of photocatalytic TiO2 particles onto PET-g-PAAc fabric has been succeeded by ultrasonic-gamma irradiation methods. Ultrasonic irradiation assisted for good distribution of TiO2 particles onto the surface of PET fabric in a uniform manner at ambient conditions. The product modify PET fabric was characterized by attenuated total reflection-Fourier transform infrared (ATR-FTIR) confirmed the grafting of COOH groups onto PET fabric. SEM images revealed a good dispersed and adherent obtained TiO2 particle onto PET fabric. Results obtained from X-ray diffraction indicating TiO2 (Degussa P25) in the anatase and rutile phases. The degradation process of three different dyes remazol red, amido black and toluidine blue from aqueous solutions by TiO2@PET-g-PAAc was investigated using modified photo reactor. It was found that decoluorization of toluidine blue was 99 % after 60 min. The reused of TiO2@PET-g-PAAc showed that the activity of TiO2@PET-g-PAAc for degradation still remained good which conclude that PET fabric makes TiO2 easily recovered, which overcomes the disadvantage of separation difficulty of common catalyst after or through degradation processing.

Synthesis, characterization and mechanical behavior of Al 3003 - TiO2 surface composites through friction stir processing

ABSTRACTAluminum 3003 alloy used in the gas turbine and aerospace applications possesses medium bearing capacity. This technical paper reports the fabrication of Al 3003 alloy/TiO2 composites using friction stir processing. The weight fraction of reinforced TiO2 particles is varied between 0% and 6% with the increment of 1.5% in sequence. The fabricated specimens have been characterized by optical microscopy (OM), Energy dispersive X-ray spectroscopy (EDAX), Field emission scanning electron microscopy (FESEM), X-ray Diffraction analysis (XRD) and electron backscattered diagram (EBSD). Composite weld zone has witnessed the homogeneous distribution of TiO2 particles. The formation of such composite by reinforcement exhibits increase in the hardness and tensile strength of the weld. Corresponding strengthening mechanism is illustrated and correlated with the characterization studies. Fractography study shows brittle to ductile transformation with the addition of TiO2 particles.

Optimization of GTAW Al 3003 weld using fabricated nanocomposite filler metal

ABSTRACTNovel Al–3 wt.% TiO2 (fillers) nanocomposite has been successfully fabricated by accumulative roll bonding method to join Al 3003 alloy with the parameters of gas tungsten arc welding process such as the shielding gas flow rate (G), the welding speed (S), and the current (I) identified by response surface methodology. After preparation of weldment, studies involving X-ray diffraction and advanced electron microscopy techniques (scanning electron microscope and transmission electron microscope) have been carried out. FESEM has revealed the presence of second-phase hard ceramic particles which are embedded homogeneously in the matrix material. Energy dispersive spectroscopy analysis indicates the absence of foreign particles other than Al, Ti, and oxides. Further, the results show that the increase in mechanical properties (hardness and ultimate tensile strength) of the weldment is due to grain refinement and uniform distribution of TiO2 nanoparticles. The analysis of variance test identified the welding speed as a significant parameter on the homogeneous distribution of TiO2 particles followed by current and gas flow rate in sequential order.

Mesocomposites Based on the Polymethylmethacrylate Matrix

This article describes the formation of a composite coating in a polymer matrix on an aluminum alloy. It is a PMMA coating (polymethylmethacrylate) with the addition of TiO2 particles. Working with these particles requires not only safety but also a suitable preparation process to obtain particles of suitable size, their subsequent homogeneous distribution in the coating (particles of this size are influenced by electrostatically attractive forces and have a strong tendency to aggravate). The first part describes the material used, sample preparation and coating process, surface roughness measurement, SEM and EDS analysis of selected samples. The aim of the research is to find out whether it is possible to use dipping and brushing techniques when coating Al-Si alloys with polymeric materials. Consequently, what can be achieved is the roughness of the surface of the coated part compared to the uncoated surface (at different particle concentrations in the spin) and the distribution of TiO2 particles on the surface of the sample.

Manufacturing of the Aluminum Metal-Matrix Composite Reinforced with Micro- and Nanoparticles of Tio2 Through Accumulative Roll Bonding Process (Arb)

Abstract The aluminum metal-matrix composites reinforced with the micro- and nanoparticles of TiO2 were manufactured in the form of sheets through the accumulative roll bonding (ARB) process which has been lately considered as a novel method under an intense plastic deformation so as to produce particulate-reinforced metal-matrix composites. Themicrostructural examinations via optic microscopy and scanning electron microscopy (SEM) depict that the distribution of TiO2 particles in the aluminum matrix is almost uniform and also the dispersion of the microparticles of TiO2 is more homogeneous than that of the nanoparticles one. Furthermore, the tensile tests demonstrate the noteworthy enhancements in the tensile strengths of the composites, compared to the Al 1100 as the virgin metal, however, by attenuating the size of the particles, i.e. from micron to nano, the composite tensile strengths are augmented. The fractographic analysis of the fracture surfaces revealed that the fracture mode in the ARB-processed Al/TiO2 composite is the shear ductile rupture type.

Nanocomposite coatings in polymeric matrices and their effect on friction coefficient

This paper deals with possibilities of production of new nanocomposite coatings in polymer matrix on aluminium alloys, namely the formation of a composite coating in a polymer matrix on an aluminium alloy. It is a PMMA coating (polymethylmethacrylate) with the addition of TiO2 particles. Working with these particles requires not only safety but also a suitable preparation process to obtain particles of suitable size, their subsequent homogeneous distribution in the coating (particles of this size are influenced by electro statically attractive forces and have a strong tendency to aggravate).The aim is to determine if the coatings will affect the surface‘s condition and its properties. The focus of the work is on selecting of the appropriate preparation of sample technology, examining the particle distribution in the coating and the effect of the coating on the coefficient of shear friction. Consequently, what can be achieved is the coefficient of shear friction of the surface of the coated part compared to the uncoated surface (at different particle concentrations in the spin) and the distribution of TiO2 particles on the surface of the sample.

Development of Photocatalytic Conversion of Glucose to Value-Added Chemicals by Supported-TiO<sub>2</sub> Photocatalysts

Biomass is an important renewable energy resource, which is used to replace the petroleum to produce chemicals. Glucose is a monomer of cellulose, which is the main component of biomass. In this work, conversions of glucose to value-added chemical by a simple method have been reported. TiO2 photocatalysts were fabricated by sol-microwave method. Value-added chemical production was successfully carried out via photocatalytic conversion of glucose with TiO2 photocatalysts. Arabinose, xylitol, gluconic acid, and formic acid were produced with photocatalytic reaction of TiO2 under UVA irradiation. The value-added products (gluconic acid, arabinose, and xylitol) can generally be further used as building blocks for biorefinery production, pharmaceutical production, and food industry. In the conventional sol-microwave method, the agglomeration of fabricated TiO2 particle was a limitation of photocatalytic activity. Therefore, the modification of TiO2 fabrication by use of zeolite as a TiO2 support was applied to increase efficiency of photocatalytic conversion of glucose and its selectivity. The effect of TiO2 dosage on zeolite (TiO2/zeolite) on photocatalytic activity and yield of products was monitored. The results from scanning electron microscopy (SEM) images indicated that zeolite supporter reduced agglomeration of spherical TiO2 particles. The well distribution of TiO2 particles on surface of zeolite particles could be observed in 15%TiO2/zeolite. It was found that the highest photocatalytic conversion of glucose (77.3%) was obtained from the use of 15%TiO2/zeolite as photocatalyst. The yields of gluconic acid, arabinose, xylitol, and formic acid were 8.6, 26.0, 3.7, and 33.89%, respectively.

Evaluation of Illumination Intensity of Plastic Optical Fibres with Tio2 Particles by Laser Treatment

Abstract CO2 laser treatment can increase the surface roughness of plastic optical fibres (POFs) with the diameter of 0.5 mm and enhance the input intensity and attenuation coefficient accordingly, which is supposed to weaken the side emission of POFs in long distance above 375 mm. TiO2 particles were applied to improve the increasing optical loss of POFs by laser treatment. POFs were first modified with fine TiO2 particles and then treated by CO2 laser with the pixel time from 30 to 120 ìs. The surface morphology was observed by scanning electron microscopy to investigate the changes of micro-structure before and after laser treatment and the distribution of TiO2 particles. The illumination intensity and attenuation coefficient were calculated and compared in two methods. It is visible that the evaluation by model LLF2 with two parts is more suitable for the fitting of experimental data and shows higher input intensity and lower attenuation than that by standard power function. Both the evaluation methods exhibit that the utilization of TiO2 particles could play an active role in the enhancement of side emission of POFs treated by CO2 laser.

Simultaneous removal of Pb2 +, Cu2 +, Zn2 + and Cd2 + from highly acidic solutions using mechanochemically synthesized montmorillonite–kaolinite/TiO2 composite

The aim of the present study was to synthesize a composite of raw interstratified montmorillonite–kaolinite clay (Mt–K) with TiO2 as an additive by mechanochemical activation and investigate its usability as low-cost adsorbent for simultaneous removal of heavy metals from acidic aqueous solutions. The composite synthesized with amorphous TiO2 (TiO2,a) showed a significantly better removal ability of heavy metals from highly acidic solutions (pH=2.0–4.0) compared with the Mt–K milled for an optimum period of time of 19h (Mt–K,m) and composite synthesized with crystalline TiO2 (TiO2,c). As both of the composites showed the same morphologies, the same distribution of TiO2 particles on the clay matrix, the same particle size distribution (PSD) dependencies and point of zero charge (pHPZC) values, it has to be noticed that the difference in the adsorption behavior lies only in the different crystalline forms of the additive, i.e. TiO2 that was used for the composite preparation. It has been shown that 20% of TiO2,a was the optimal amount of an additive in the composite to achieve improved adsorption ability.

Effect of titanium dioxide (TiO2) on largely improving solar reflectance and cooling property of high density polyethylene (HDPE) by influencing its crystallization behavior

In this study, the different crystal forms of titanium dioxide (TiO2) were added into high density polyethylene (HDPE) to fabricate cool material. Crystal structure, crystallization behavior, crystal morphology were investigated by wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC) and polarized optical microscope (POM). Scanning electron microscope (SEM) was applied to observe dispersion of TiO2 particles in the HDPE matrix and the cross section morphology. The solar reflectance and actual cooling property were evaluated by UV–Vis–NIR spectrometer and a self-designed device. By adding TiO2 particles into HDPE matrix, the polymer chain could crystallize into more perfect and thermal stable lamella. The presence of TiO2 particles dramatically increased the number of nucleation site therefore decreased the crystal size. The subsequent solar reflectance was related to the degree of crystallinity, the spherulite size of HDPE, refractive index, and distribution of TiO2 particles in HDPE matrix. It was found the rutile TiO2 could largely improve the total solar reflectance from 28.2% to 51.1%. Finally, the temperature test showed that the composites had excellent cooling property, which was in accordance with solar reflectance result.

Spatial point statistics for quantifying TiO2 distribution in paint

Spatial point statistics such as Clark-Evans R, Ripley’s K, and the neighborhood distribution function (NDF) have been used to study the spatial distribution of TiO2 particles in sections of paint films. Particle coordinates were obtained from electron micrographs. Ripley’s K and the NDF are particularly useful in detecting segregation, randomness, or aggregation at various length scales. Other statistics such as aggregate-size distributions were also calculated. The spatial distribution in well-dispersed paints studied here is essentially random and observed aggregates are explained by the spatial inhomogeneity inherent in the random distributions. The aggregate-size distributions are approximately logarithmic for well-dispersed paints. Mean aggregate size increases with increasing pigment volume concentration (15–30%PVC), even though the spatial distribution remains random, showing that crowding at high PVC is a heterogeneous process. Mean aggregate sizes determined by microscopy correlate well with opacity and other paint properties. Computer simulation shows that spatial point and aggregate-size analysis of points in 2-D slices taken from a 3-D volume underestimate absolute aggregate sizes, but that spatial statistics and aggregate distributions correlate strongly with those obtained from the original 3-D distribution. Therefore, results from analysis of micrographs are expected to translate to the 3-D paint film. As expected, coarse extenders crowd the TiO2 and increase aggregation, but highly anisodiametric particles appear less deleterious than blocky particles.

The application of principal component analysis and gray relational method in the optimization of the melt spinning process using the cooling air system

This study attempted to optimize the manufacturing process of polyethylene terephthalate (PET) and titanium dioxide-containing (TiO2) composite fibers. The composite fiber is made by the melt spinning processing method, and has the characteristics of the high strength of PET and the sterilization function of TiO2. To obtain the optimal processing parameters, this study applied the Taguchi method in planning the research experiment, and set one parameter of two levels and seven parameters of three levels using the L18 orthogonal array. The flow equation was used to design a cooling air system for the manufacturing, and the results showed that using one parameter of two levels can give a stable air pressure to cool the fiber to obtain the characteristics of excellent quality. Finally, field emission scanning electron microscope (FE-SEM) was used to observe the distribution of TiO2 particles in the PET fiber produced in the experiment, in order to verify the experimental effectiveness. This study used principal component analysis combined with the gray relational method to obtain the optimal parameters of the experiment, because the former has the advantage of data simplicity, while the latter can determine the factors influencing power ranking. Confirmation experiments were conducted to test the quality characteristics, and found that the properties of the fiber produced with the optimal parameters showed improvements.

Extruded expanded polystyrene sheets coated by TiO2 as new photocatalytic materials for foodstuffs packaging

Nanostructured, photoactive anatase TiO2 sol prepared under very mild conditions using titanium tetraisopropoxide as the precursor is used to functionalise extruded expanded polystyrene (XPS) sheets by spray-coating resulting in stable and active materials functionalised by TiO2 nanoparticles. Photocatalytic tests of these sheets performed in a batch reactor in gas–solid system under UV irradiation show their successful activity in degrading probe molecules (2-propanol, trimethylamine and ethene). Raman spectra ensure the deposition of TiO2 as crystalline anatase phase on the polymer surface. The presence of TiO2 with respect to polymer surface can be observed in SEM images coupled to EDAX mapping allowing to monitor the surface morphology and the distribution of TiO2 particles. Finally thermoforming of these sheets in industrial standard equipment leads to useful containers for foodstuffs.

Study of PET/PP/TiO2 microfibrillar‐structured composites, Part 2: Morphology and mechanical properties

AbstractUncompatibilized and compatibilized (polypropylene grafted maleic anhydride as compatibilizer) polyethylene terephthalate (PET)/polypropylene (PP)/TiO2 microfibrillar composites (MFC) were prepared by injection molding of the pelletized PET/PP/TiO2 drawn strands. The morphology of PET fibrils and the distribution of TiO2 particles in the composites were examined. After injection molding the preferential location of TiO2 particles is still preserved. Because of the reinforcement effect of PET fibrils, the tensile properties and impact strength of the PET/PP MFC are improved compared with the pure PP. Incorporation of TiO2 particles results in decrease of both tensile strength and impact strength of the composites. However, the compatibilized PET/PP/TiO2 MFC demonstrate better mechanical properties compared with the uncompatibilized ones. DMA analysis shows that the glass transition temperature (Tg) of PET in the uncompatibilized PET/PP/TiO2 MFC and the Tg of PP in the compatibilized PET/PP/TiO2 MFC are elevated by about 2°C. The elevation of Tg is attributed to the preferential location of TiO2 particles in the composites. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Distribution of TiO2 particles in the olfactory bulb of mice after nasal inhalation using microbeam SRXRF mapping techniques

The characterization of different sized TiO2 (25 nm, 80 nm, and 155 nm) was carried out by transmission electron microscopy (TEM) and the micro-distributions of TiO2 in the olfactory bulb of mice after nasal inhalation were investigated by microbeam SRXRF mapping techniques. The results show that TiO2 particles can be translocated to the olfactory bulb through the olfactory nerve system after inhalation. The distributions of Fe, Cu, and Zn in the olfactory bulb were also studied.

The effect of nanometer particles of titanium oxide on the protective properties of skin in the UV region

This paper discusses the efficiency of the attenuation of UV radiation by nanoparticles of titanium oxide (TiO2) incorporated into the horny layer of the skin. The distribution of TiO2 particles was determined experimentally. A program implementing the Monte Carlo method was used to model photon propagation in a 20-µm thick horny layer of the skin, partially filled with TiO2 particles. The dependences are obtained for the transmitted, reflected, and absorbed components of UV radiation with a wavelength of 310 nm as a function of the concentration of TiO2 particles of various sizes (40-175 nm). It is established that the most efficient particles for protecting the deep layers of skin containing living and, in particular, immune-competent cells from UV radiation are particles 62 nm across.

TiO2 nanoparticles as an effective UV-B radiation skin-protective compound in sunscreens

Protecting human skin against harmful UV-B radiation coming from the sun is currently a problem. Due to the decreased thickness of the ozone layer, a more dangerous amount of UV-B light reaches the surface of our planet. This causes increased frequency of skin diseases. Titanium dioxide (TiO2) fine particles are embedded with sunscreens into the skin to effectively attenuate UV-B radiation. This study evaluates the most appropriate size of such particles assuming they are spheres. The distribution of TiO2 particles within the skin, achieved with topically applied sunscreens, is determined experimentally by the tape-stripping technique. Computer code implementing the Monte Carlo method is used to simulate photon migration within the plain 20 µm thick horny layer matrix partially filled with nano-sized TiO2 particles. Dependences of harmful UV-B radiation of 307–311 nm absorbed by, backscattered from and transmitted through the horny layer on the concentration of TiO2 particles are obtained and analysed. As a result, particles of 62 nm are found to be the most effective in protecting skin against UV-B light.