TiO2-coated Fibers Research Articles

Enhancement of the ultraviolet resistance and interfacial adhesion of copolymerized aramid fibers with a titanium dioxide coating

Copolymerized aramid fibers (CAFs) hold considerable promise as high-performance materials because of their mechanical strength and thermal resistance. However, their low ultraviolet (UV) resistance and poor matrix adhesion limit their applications. In this study, a TiO2 coating is applied to the surfaces of CAFs through a solution-dipping process to enhance their UV resistance and interfacial adhesion. The fibers are dipped in aqueous solutions with varying concentrations of TiCl3, serving as a precursor, at temperatures in the range 50–90 °C. Changes over time are observed in the fibers using scanning, the TiO2 particles grow and completely coat the fiber surfaces. The TiO2-coated fibers demonstrate a high UV resistance, as evidenced by the tensile strength retention rate of approximately 80%, which is significantly higher than the 55% retention rate observed for the untreated fibers after 24 h of light irradiation at 600 W. The TiO2 coating enhances the interfacial strength between the TiO2 layer and CAF surface through hydrogen and physical bonding. Consequently, the interfacial strength is approximately 2.3 times than that of the untreated fibers. These results emphasize the potential of this simple TiO2 dip-coating method for various practical applications, particularly in extreme environments.

XPS and FTIR Studies of DC Reactive Magnetron Sputtered TiO2 Thin Films on Natural Based-Cellulose Fibers

Natural based-cellulosic fibers are trending due to the global awareness regarding environmental health and because their properties make them a great alternative to the synthetic fibers. However, these fibers also have some hindrances that can be solved with their functionalization. The present study concerns modification of the surface of natural based-cellulosic fibers extracted from stems of the ginger lily plant (Hedychium gardnerianum) with TiO2 films deposited by DC magnetron sputtering using a titanium (Ti) target. A detailed characterization of the TiO2-coated fibers was investigated by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The results revealed that the sputtered TiO2 films can be attached to the ginger lily fibers mainly by their OH groups. XPS analysis further shows that C–OH group is not dominant, which means that no pure cellulose is present at the surface.

Enhanced UV Photo-Stabilization of PBO Fibers via Sol-Gel Surface Modification

PBO fiber is the most excellent high performance fiber. But it is a kind of photosensitive material and is prone to degrade under ultraviolet (UV) radiation, which results in the changes of the fiber mechanical properties, finally affects the using of the material. In present paper, Titanium tetrabutoxide was used as solgel precursor of a nanosized TiO2coating to improve the photostability of PBO fibers. The nanosized TiO2coating was characterized by XRD. The influence of the coating on UV-durability of PBO was investigated by an accelerated UV-ageing method. Results of mechanical measurement showed that after exposing to UV light for 160 h, the fibers without TiO2coating degraded sharply, 7.01% of strength and 11.42% of break extension only remained, whereas 45.61% of strength and 68.56% of break extension still remained for the TiO2coated fibers. SEM analysis showed no significant surface morphological change on the coated fibers after the exposure, while some latitudinal crack fractures appeared on the uncoated PBO fibers.

Effect of TiO2 deposition on the mechanical properties of a carbon-fiber-reinforced bismaleimide composite

In order to improve the mechanical properties of carbon-fiber-reinforced bismaleimide (CF/BMI) composites, TiO2 was deposited on the carbon fibers. The short-beam shear and mechanical properties of the composites were investigated. Both raw and TiO2-coated CFs were utilized for their fabrication. The tensile strength of the composites, both with raw and TiO2-coated fibers, grew with increasing filler content. The tensile strength of the CF/BMI composites with treated fibers, at all mixing ratios, was found to be by 18% higher than that of the composites with untreated ones. The surface morphologies of fracture surfaces of the composites were recorded using the scanning electron microscopy (SEM) to gain information about the interfacial fiber-matrix adhesion in the composites.

Design of Hot Roll Press to Fabricate TiO<sub>2</sub>-Coated Fiber for Decomposing Rhodamine B in Water

We have designed new coating equipment for applying nanoparticles of TiO2 on nylon fiber surfaces. A roll hot press with a motor speed of 1740 rpm was able to synthesis ±227 cm/min coated fibers. This equipment is simple and does not require any adhesive materials for attaching Ti02 nanoparticles on the fiber surface. The fiber was passed through a dispersion of TiO2 nanoparticles and then passed through a roll hot press at heating temperature between 600C and 700C. The TiO2-coated fibers were then used for decomposing rhodB-solutions under solar illumination. We observed the TiO2-coated fibers did not affect to properties of TiO2 as catalyst in photocatalysis. The best result was observed when 0,5 gr TiO2-coated fibers were suspended into 250 ml of rhodB-solution in water with a concentration of 1,6 %w/v.

Preparation and the light transmittance of TiO2 deposited fabrics

Nanoscale titanium dioxide (TiO2) films were deposited on the surface of polyester nonwovens by using direct current reactive magnetron sputtering. The effect of oxygen flow on the surface structures and properties of the fabrics was investigated in this article. The surface morphology, microstructure, and the chemical composition of TiO2-coated fibers were characterized by atomic force microscope, X-ray diffraction, and X-ray photoelectron spectroscopy. The effect of oxygen flow on deposition rate, white degree, and light transmission properties of the fabrics with nanoscale TiO2 films were examined. The test results proved that the oxygen flow was a key factor in sputter processing. The deposition speed decreased and the white degree of the fabric increased with increasing oxygen flow. The ultra-violet absorption by the polyester nonwoven fabric with TiO2 coatings was also enhanced as the oxygen flow increased in a proper range.

Preparation and Characterization of TiO2-Coated Optical-Fiber in a Photo Reactor

An optical-fiber photo reactor (OFPR) was designed and assembled to provide uniform light distribution inside the reactor, which spread light energy more efficiently than a traditional fixed-bed reactor. TiO2 films were coated on optical fibers using the dip-coating method. Titania solutions were prepared through the thermal hydrolysis of titanium butoxide, commercial Hombikat XXS100 solution, and Degussa P25 suspension for comparison. The thicknesses of the films ranged from 60 to 600 nm after calcination at 500℃, and the sizes of the nanocrystals in the TiO2 films were 15-25 nm, as estimated from SEM micrographs. Anatase phase was found from the XRD patterns in all the TiO2 films. The profilemeter and ASTM D3359 adhesion test results showed that uniform TiO2 films were formed with strong adhesion using the thermal hydrolysis and Hombikat XXS100 solutions, while those coated with P25-suspension exhibited poor adhesion on a glass surface. The contact angle of the water decreased to almost zero within 30 minutes under UV-light irradiation and then recovered to the initial contact angle in darkness, implying super hydrophilicity and perfection of the TiO2 films. Ammonia was photocatalytically decomposed in the OFPR under artificial light irradiation, indicating good photocatalytic reactivity of the TiO2-coated fibers.

BASF incorporates sunblocker-grade TiO 2 in nylon fabric

A preliminary optical fiber reactor (OFR) that employs bare quartz fibers as a light-transmitting support of TiO2 was tested for gas treatment by investigating photocatalytic oxidation of acetone in air (50–750 ppmv). Using one or four TiO2-coated fibers in a continuous flow photoreactor, a steady-state conversion up to 80% was achieved at ambient temperature and pressure. The kinetic behavior of the acetone conversion in this study could be described by zero-order kinetics. The characteristics of coated-optical fibers were quantitatively analyzed and their use in photocatalytic gas treatment was discussed in detail. All the acetone molecules degraded was quantitatively converted to CO2 with no intermediates detected. No noticeable deactivation was observed within a few hours’ operation under the present experimental conditions. The conversion of acetone linearly increased with the incident light intensity without showing any sign of saturation. The transmitted light intensity through a TiO2-coated optical fiber exponentially decreased along the fiber, showing 90% extinction within 30 cm. The photocatalytic conversion measured as a function of the coated-fiber length showed a similar trend. An optimal coating thickness was found at around 1.5 μm above which the photocatalytic efficiency was reduced. The presence of water vapor reduced the reactivity due to the competitive adsorption on active surface site with acetone. While a measurable conversion of acetone was observed in the absence of O2, increasing O2 concentration up to 15% effectively enhanced the conversion.

Investigation on TiO2-coated optical fibers for gas-phase photocatalytic oxidation of acetone

A preliminary optical fiber reactor (OFR) that employs bare quartz fibers as a light-transmitting support of TiO2 was tested for gas treatment by investigating photocatalytic oxidation of acetone in air (50–750ppmv). Using one or four TiO2-coated fibers in a continuous flow photoreactor, a steady-state conversion up to 80% was achieved at ambient temperature and pressure. The kinetic behavior of the acetone conversion in this study could be described by zero-order kinetics. The characteristics of coated-optical fibers were quantitatively analyzed and their use in photocatalytic gas treatment was discussed in detail. All the acetone molecules degraded was quantitatively converted to CO2 with no intermediates detected. No noticeable deactivation was observed within a few hours’ operation under the present experimental conditions. The conversion of acetone linearly increased with the incident light intensity without showing any sign of saturation. The transmitted light intensity through a TiO2-coated optical fiber exponentially decreased along the fiber, showing 90% extinction within 30cm. The photocatalytic conversion measured as a function of the coated-fiber length showed a similar trend. An optimal coating thickness was found at around 1.5μm above which the photocatalytic efficiency was reduced. The presence of water vapor reduced the reactivity due to the competitive adsorption on active surface site with acetone. While a measurable conversion of acetone was observed in the absence of O2, increasing O2 concentration up to 15% effectively enhanced the conversion.