A facile solid-state heating method for preparation of poly(3,4-ethelenedioxythiophene)/ZnO nanocomposite and photocatalytic activity

Poly(3,4-ethylenedioxythiophene)/zinc oxide (PEDOT/ZnO) nanocomposites were prepared by a simple solid-state heating method, in which the content of ZnO was varied from 10 to 20 wt%. The structure and morphology of the composites were characterized by Fourier transform infrared (FTIR) spectroscopy, ultraviolet-visible (UV-vis) absorption spectroscopy, X-ray diffraction (XRD), and transmission electron microscopy (TEM). The photocatalytic activities of the composites were investigated by the degradation of methylene blue (MB) dye in aqueous medium under UV light and natural sunlight irradiation. The FTIR, UV-vis, and XRD results showed that the composites were successfully synthesized, and there was a strong interaction between PEDOT and nano-ZnO. The TEM results suggested that the composites were a mixture of shale-like PEDOT and less aggregated nano-ZnO. The photocatalytic activity results indicated that the incorporation of ZnO nanoparticles in composites can enhance the photocatalytic efficiency of the composites under both UV light and natural sunlight irradiation, and the highest photocatalytic efficiency under UV light (98.7%) and natural sunlight (96.6%) after 5 h occurred in the PEDOT/15wt%ZnO nanocomposite.     

Waterborne acrylic–polyaniline nanocomposite as antistatic coating: preparation and characterization

An antistatic and electrically conductive acrylic–polyaniline nanocomposite coating was successfully synthesized by interfacial polymerization of aniline in the presence of acrylic latex. The acrylic latex was prepared through emulsion polymerization, and aniline was polymerized by in situ interfacial polymerization at the interface of acrylic latex/chloroform phase. Fourier transform infrared spectroscopy (FTIR), UV–Vis spectroscopy and CHNS elemental analysis revealed the existence of 6.24 wt% emeraldine salt of polyaniline (PAni) in the dried film of the nanocomposite. Scanning electron microscopy (SEM) confirmed the presence of colloidal polymer particles in the aqueous phase which was confirmed to have some advantages, including prevention of aggregation of particles, dispersibility improvement and enhancement of the PAni nanofibers aspect ratio in the acrylic polymer matrix. According to SEM results, PAni fibers with the length ranging from 12 to 67 µm and diameters between 0.078 and 1 µm, highly dispersed in the acrylic polymer matrix, were successfully synthesized. Thermal, electrical and mechanical properties of the acrylic copolymer were significantly affected by PAni incorporation. The onset degradation temperature in thermogravimetric analysis revealed that the thermal stability of the nanocomposite was improved compared to that of the pure acrylic copolymer. The nanocomposite film showed electrical conductivity of about 0.025 S/cm at room temperature, along with satisfactory mechanical properties, attractive as an antistatic material in coating applications.     

A novel approach for the synthesis of highly active ZnO/TiO2/Ag2O nanocomposite and its photocatalytic applications

The present work is focused on the preparation of hybrid ZnO/TiO₂/Ag₂O nanocomposite for enhanced photocatalytic activity. The resultant samples are characterized by using XRD, SEM, EDX, HR-TEM, UV-DRS, BET and XPS techniques. X-ray diffraction analysis indicates the co-existence of wurtzite, anatase and cubic phases in ZnO/TiO₂/Ag₂O nanocomposite. The band gap energy value of the photocatalyst is 3.39 eV, which has been evidenced from UV–visible diffuse reflectance spectroscopy measurements. Photocatalytic degradation of methylene blue dye has been investigated by using UV–visible spectrophotometer. From the result, it has been concluded that ZnO/TiO₂/Ag₂O nanocomposite has proven to be an efficient photocatalyst under UV irradiation when compared to that of mono and binary oxide systems. Further, the possible photodegradation mechanism is proposed to support the enhancement of photocatalytic activity towards degradation of dyes.     

UV‐curable nanocomposites containing zirconium vinylphosphonate or zirconia

UV‐cured nanocomposite films were prepared from acrylic monomer and two types of nanomaterial: zirconium vinylphosphonate and zirconia, in the presence of a photoinitiator. The films were characterized by FTIR, SEM, and AFM. FTIR spectra showed the disappearance of band assigned to the CC group both of monomer and zirconium vinylphosphonate by polymerization and the presence of the phosphonate group in polymer. The influence of zirconium vinylphosphonate and zirconia content on thermooxidative degradation of polymeric films was studied by thermogravimetry. SEM and AFM images showed that nanomaterials are dispersed in polymer matrix with no macroscopic phase separation. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

“Effect of nano-ZnO particles on the corrosion behavior of alkyd-based waterborne coatings”

A nano-composite was formed by incorporating nano-ZnO in a specially developed alkyd-based waterborne coating to different loading levels. The nano-ZnO based composite coatings were applied on mild steel substrate by dipping. The coated panels were subjected to various test environments like salt-spray, humidity, UV and mechanical tests like scratch and abrasion. The improvement in electrochemical performance and mechanical properties of the composite coatings were evaluated using various analytical techniques. FTIR technique was used to investigate the interaction between nano-ZnO particles and the polymer functionalities. Differential scanning calorimetry (DSC) was done to study the curing behavior of nano-composite coatings. SEM and AFM were used to investigate dispersion of nano-ZnO particles and the changes in the surface behavior of the coatings before and after exposure to the test environment. The result showed that, with increase in the concentration of nano-ZnO there was an improvement in the corrosion resistance, UV resistance and mechanical properties of the coatings indicating the positive effect of addition of nano-ZnO particles in the coatings.     

Effect of nano-ZnO particles on the corrosion resistance of polyurethane-based waterborne coatings immersed in sodium chloride solution via EIS technique

Nano-composite coatings were formed by incorporating 3 wt% nano-ZnO in a polyurethane-based waterborne coating. The nano-ZnO based composite coatings were applied on standard phosphated steel panels by cathodic electrodeposition. The electrodeposited nano-composite coatings were then baked for 20 min at 165 °C. To investigate the corrosion resistance of the coatings, the coated panels were immersed in 3.5 wt% NaCl solutions for 2880 h (120 days). The improvement in corrosion performance of the composite coatings was evaluated using electrochemical impedance spectroscopy technique. It was found that the films containing nano-sized ZnO particles show a corrosion resistance of 2 orders of magnitude higher than that of the neat films.     

Comparison on photocatalytic degradation of gaseous formaldehyde by TiO2, ZnO and their composite

In order to compare the photocatalytic properties of TiO₂, ZnO and their composite in the gas phase pollutant environment, nanocomposite with different mole ratios of TiO₂/ZnO were designed to degrade gaseous formaldehyde. The results showed that the rate constant of TiO₂ for formaldehyde degradation was 0.05 min^?1 which was two orders of magnitude larger than that of ZnO in our experiment. Through comprehensive analysis of UV–vis diffuse reflectance (UV–vis) spectra, photoluminescence spectra (PL) and energy band diagram, it was found that the differences of photocatalytic properties between ZnO and TiO₂ may mainly originate from the increased recombination of photoinduced charges in ZnO. The photocatalytic properties of TiO₂/ZnO composite for formaldehyde degradation were much worse than those of TiO₂, while better than those of ZnO. The addition of a small amount of ZnO weakened the photocatalytic properties of TiO₂. It may be attributed to that the recombination action of photoinduced electron–hole pairs in ZnO.     

Photocatalytic Decolorization of Dye Effluent Using Radiation Developed Polymeric Nanocomposites

In this study [acrylic acid/p(N-vinyl-2-pyrrolidone)] (AAc/PVP) hydrogel was prepared using gamma irradiation technique. The prepared hydrogel was used as a template for in situ preparation of ZnO photocatalyst up to three deposition cycles. The structure, the thermal property, and the surface morphology of (AAc/PVP/ZnO) nanocomposite were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), transmission electron microscope (TEM) and scanning electron microscope (SEM) techniques. The photocatalytic activity of the obtained nanocomposite was tested for the degradation of methyl blue dye (MB) in the aqueous medium using UV-light. The effect of operational parameters on the degradation of MB such as UV irradiation time, pH, and initial dye concentration were examined. It was found that complete decolorization of MB dye was achieved after 45 min at pH 4. The degradation rate fitted the pseudo-first-order model and the rate of the photocatalytic reaction of the first preparation cycle of ZnO was higher than that of the third preparation cycle.     

Cellulose reinforced-TiO<Subscript>2</Subscript> photocatalyst coating on acrylic plastic for degradation of reactive dyes

In this study, cellulose reinforced-TiO₂ (C-T) film was coated on acrylic plastic sheet and used for UV photocatalytic degradation of four reactive dyes viz., Reactive Black 5, Reactive Red 11, Reactive Orange 16, and Reactive Red 2 in a falling film reactor (FFR). Slurry comprising cellulose and TiO₂ in suitable weight proportions (5, 10, 15, and 25 wt% cellulose) was prepared and a C-T film was obtained by brush coating on acrylic plastic sheet. The composition yielding adherent film and efficient for the dye degradation was identified. The effect of hydraulic flow rate and solution pH on the stability of the C-T films was also investigated. The photocatalytic coating containing 15 wt% cellulose was found to be adherent and efficient for dye degradation. The photodegradation of the reactive dyes, monitored in terms of decolorization (>80%), and reduction in total organic carbon (TOC) during 5 h followed pseudo first-order kinetics. The mineralization efficiency at 5 h treatment using 15 wt% C-T coating was in the range 75.4–83.3% for all the dyes. On the basis of optical microscopy images, the stability of the C-T films obtained from 15 wt% cellulose was attributed to the interlacing of the cellulose fibers that reinforced the TiO₂ coating.     

微波辅助制备纳米ZnO及其光催化降解染料的性能

以硝酸锌、氢氧化钠为原料,聚乙二醇400(PEG 400)为溶剂,采用微波加热共沉淀法制备纳米ZnO,并采用X射线衍射、场发射电镜及紫外-可见漫反射对样品进行表征;考察纳米ZnO对结晶紫(CV)及刚果红(CR)的光催化降解性能,以λ=365nm的紫外光为光源,考察了催化剂投加量、染液浓度、pH值以及催化时间对催化效率的影响。实验结果表明,在较少的投加量下,纳米ZnO对50mg/L的CV和CR染液的降解率可分别达到98.8%和97.4%,pH值对两种染料的光催化效果影响不大。CR及CV染液的光催化降解均符合一级动 力学。     

A hybrid polyacrylate/OMMT nanocomposite latex: Synthesis,characterization and its application as a coating binder

Hybrid latex particles have an increasing importance in industrial applications especially for high performance waterborne coatings. They provide combined properties of different phase compositions for the final polymer which can also be enhanced by additives such as nanoclays. The present study describes the preparation of a hybrid polyacrylate/OMMT nanocomposite latex via two stage in situ emulsion polymerization with a low emulsifier content (1 wt%) which is usually a challenge for the preparation of stable polymer/OMMT nanocomposite latexes. The obtained nanocomposite latex was stable and had a fine average size diameter of 151 nm with a very narrow size distribution. The copolymer films exhibited a well exfoliated structure observed by WAXD and TEM. Other polymer properties were investigated by FTIR, DSC, TGA, DMTA and rheological measurements. The results indicated that the addition of clay even in low amount (2 wt%) yielded significantly improved mechanical and thermal properties of the final polymer. In addition, the nanocomposite latex was also applied on leathers as coating binder in a finishing formulation and the results of the performance tests revealed substantially increased rubbing and heat resistance whereas a slight decrease was observed at water vapor permeability of the coated leathers.     

An eco-friendly highly stable and efficient Ni-C-S codoped wurtzite ZnO nanoplate: a smart photocatalyst for the quick removal of food dye under solar light irradiation

In recent years, semiconductor photocatalysis has become more and more attractive and important since it has great potential to contribute to such environmental problems. This work investigates the photodegradation of tatrazine using Ni, C and S codoped ZnO (Ni-C-S/ZnO) nanoplates synthesized by the co-precipitation method. The synthesized photocatalyst was characterized by UV–visible-diffuse reflectance spectroscopy (UV–vis-DRS), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) techniques. Ni-C-S/ZnO were found to be more photoactive than ZnO, Ni-ZnO and C-S/ZnO for the degradation of tatrazine under solar light irradiation. Ni, C and S, with a moderate amount (0.5:0.5:0.5:1) doped on ZnO, can act as electron traps and suppress the photogenerated electron–hole pair recombination and result in the improvement of photocatalytic performance samples. The optimum condition for 94% degradation was found to be 300 mL of 10 µM of dye solution along with 0.1 g/L of Ni-C-S/ZnO under solar light irradiation within 90 min. From this, the Ni-C-S/ZnO sample exhibited maximum photocatalytic efficiency for the degradation of tatrazine under solar light irradiation.     

Preparation and characterization of UV‐curable ZnO/polymer nanocomposite films

A series of novel nano‐ZnO/polymer composite films with different ZnO contents was prepared through incorporation of pre‐made colloidal ZnO particles into monomer mixtures of urethane‐methacrylate oligomer and 2‐hydroxyethyl methacrylate, followed by ultraviolet (UV) radiation‐initiated polymerization. The colloidal ZnO nanoparticles with a diameter of 3–5 nm were synthesized from zinc acetate and lithium hydroxide in ethanol via a wet chemical method. In order to stabilize and immobilize the ZnO particles into the polymer matrix, the ZnO nanoparticles were further capped using 3‐(trimethoxysilyl)propyl methacrylate. Thermogravimetric analyses show that the ZnO nanoparticles were successfully incorporated into the polymer matrix and these ZnO/polymer composites have a good thermal stability. Transmission electron microscopy studies indicate the ZnO nanoparticles were uniformly dispersed in the polymer and they remained at the original size (3–5 nm) before immobilization. All nanocomposite films with ZnO particle contents from 1 to 15 wt% show good transparency in the visible region and luminescent properties. In addition, composite films with high ZnO content (>7 wt%) are able to absorb UV irradiation below 350 nm, indicating that these composite films exhibit good UV screening effects. Copyright © 2006 Society of Chemical Industry     

Studying the effects of micro and nano sized ZnO particles on the corrosion resistance and deterioration behavior of an epoxy-polyamide coating on hot-dip galvanized steel

The effects of micro and nano sized ZnO particles on the corrosion resistance and hydrolytic degradation of an epoxy coating were studied. Different analytical techniques including scanning electron microscope (SEM), electrochemical impedance spectroscopy (EIS), dynamic thermal mechanical analysis (DMTA) and nano-indentation were utilized to evaluate the hydrolytic degradation as well as the corrosion resistance of the coatings in exposure to 3.5 wt% NaCl solution. It was found that the epoxy coating resistance against corrosive electrolyte was significantly improved using nano and micro sized ZnO particles. The corrosion resistance of the nanocomposite was considerably greater than the one reinforced with the micro-ZnO particles. Moreover, the resistance of the coating reinforced with the nano sized particles against hydrolytic degradation in exposure to the corrosive electrolyte was considerably greater than the one reinforced with the micro sized particles. Decrease in both nano hardness and cross-linking density of the epoxy coating reinforced with nanoparticles after exposure to the corrosive electrolyte were considerably lower than the blank sample and the sample reinforced with the micro sized ZnO particles. Using nano sized particles the coating adhesion loss decreased.     

Synthesis and characterization of ZnO NRs with spray coated GO for enhanced photocatalytic activity

Zinc oxide nanorods, ZnO NRs, were synthesized on a clean glass and coated with graphene oxide (GO) using spray coating method to enhance the photocatalytic activity in wastewater treatment. The ZnO NRs were synthesized using the solution process synthesis that was optimized using Taguchi method. Several synthesis parameters have been optimized and studied to determine the best synthesis parameter to grow ZnO NRs for the photodegradation of organic contaminants. Field emission scanning electron microscopy (FESEM) with EDX, X-ray diffraction (XRD), Raman, ultraviolet visible near-infrared (UV-VIS-NIR), and photoluminescence (PL) spectroscopies were used to investigate the structural and optical properties of the produced nanorods. FESEM images revealed the vertical growth of ZnO NRs as well as layers of GO covering the ZnO NRs' top surface. The Raman study demonstrates the combination peak of GO and ZnO, hence proving the GO layer's successful coating. After the GO coating, decrease in the bandgap of the synthesized photocatalyst was detected by PL and UV–Vis absorption measurements. Under UVC exposure with treatment time of 6 h, the degradation of MB with ZnO NRs/GO photocatalyst reached a degradation percentage of 97.86%, which is greater than the degradation percentage achieved using pristine ZnO NRs, which is 93.28%. The results validated that the coating of GO enhances the photocatalytic activity of the host material, ZnO NRs.     

Fabrication of asymmetric zinc oxide/carbon nanotubes coated polysulfone photocatalytic nanocomposite membrane for fouling mitigation

Membrane filtration is a favorable option in water reclamation from contaminated water source, nevertheless, inevitable membrane fouling which greatly shortens membrane longevity and separation efficiency. The paper aimed to mitigate the membrane fouling through the formation of an asymmetric PSF-ZnO/CNTs photocatalytic nanocomposite membrane. Instead of direct blending the photocatalyst into polymer matrix, the asymmetric nanocomposite membrane was prepared with prior formation of a self-assembled ZnO/CNTs photocatalyst layer through wet-processing technique followed with coating of PSF support layer via phase inversion method. The morphology of the nanocomposite membrane was characterized to confirm the formation of the asymmetric structure. The effect of ZnO/CNTs photocatalyst loading on the pore characteristic and antifouling properties of the PSF-ZnO/CNTs nanocomposite membrane in dye remediation were assessed. The incorporation of ZnO/CNTs layer was found to endows the membrane with ability to photodegrade methylene blue. The PSF-ZnO/CNTs membrane with 0.038 g ZnO/CNTs photocatalyst loading (M5) showed the greatest flux recovery ratio (98.46%) and the lowest irreversible fouling ratio (1.54%) while exhibited decent water permeability about 29.99 L/m²h without compromise the methylene blue rejection rate (91.04%).     

Facile synthesis and investigation of NiO–ZnO–Ag nanocomposites as efficient photocatalysts for degradation of methylene blue dye

In the present study, NiO–ZnO–Ag photocatalytic nanocomposites were synthesized using two-stage precipitation method. The synthesized composite powders were investigated and characterized using different techniques including XRD, FESEM, FT-IR, TGA and UV–Vis. XRD results showed that by increasing the Ag content, the crystallite size of ZnO decreased. FESEM micrographs showed that addition of Ag could lead to formation of more uniform particles in the size range of 30–500 nm. Diffuse reflectance spectroscopy results confirmed that addition of Ag nanoparticles led to the increase of light absorption, which was attributed to the plasmon surface resonance of Ag. Band gap energies of NiO–ZnO, NiO–ZnO–5%Ag, NiO–ZnO–3%Ag, NiO–ZnO–1%Ag and ZnO–1%Ag were estimated to be 3.13, 3.14, 3.147, 3.19 and 3.17 eV, respectively. Investigation of degradation process showed that by adding up to 1 wt% Ag to NiO–ZnO composite led to the increase of methylene blue degradation from 67% to 94%, but further addition resulted in decrease of degradation.     

Improved photocatalytic performance of Gd and Nd co-doped ZnO nanorods for the degradation of methylene blue

This paper reports the synthesis of pure ZnO, Gd and Nd co-doped ZnO nanorods based nanocomposites via simple hydrothermal method. Subsequently, the prepared photocatalysts were characterized using XRD, SEM/EDX, TEM, UV–visible and PL spectroscopy. The XRD results demonstrate that Gd and Nd ions were incorporated into ZnO lattice in the synthesized ZnO based nanocomposites and showed hexagonal wurtzite structure. The SEM and TEM results show that nanorods having nanoscale diameter and length were successfully synthesized by hydrothermal method. The UV–visible spectroscopy verified that the band gap of ZnO was reduced due to incorporation of Gd and Nd into ZnO photocatalyst. Similarly, Gd and Nd incorporation into ZnO was found effective to reduce the recombination of electrons and holes as confirmed by PL spectroscopy. Moreover, the prepared nanocomposites with various atomic ratios (0.5–2%) were tested for photocatalytic degradation of methylene blue (MB), under visible light irradiation. The highly efficient and optimized 1.5% Nd/ZnO nanocomposite demonstrated enhanced photocatalytic performance for the degradation of methylene blue compared to pure ZnO and other nanocomposites. Furthermore, the recycling results show that the 1.5% Nd/ZnO nanocomposites displayed good stability and long-term durability. These finding suggest that the ZnO based nanocomposite could be efficiently used in various energy and environmental applications.     

Assessment of UV-permeability in nano-ZnO filled coatings via high throughput experimentation

The degree of UV protection afforded by nano-ZnO in a polyurethane/acrylic clear topcoat was investigated. The influence of nano-ZnO concentration and dry film thickness on the optical properties (e.g., UV permeability and visible transmittance) of the coating was probed using a library of 28 samples that were prepared by high throughput techniques. A model for predicting the UV permeability of nano-ZnO filled coatings was developed and the nano-ZnO loading condition required to block >99% UV radiation was determined to be 2.0 g/m². This model can be used to assist in the development of coatings and other polymeric systems embedded with nano-ZnO to protect the coating and underlying materials (i.e., substrate) from UV degradation.

水性紫外光木器涂料的研制

以水性UV丙烯酸酯树脂、水性UV脂肪族聚氨酯丙烯酸酯树脂为基料制备成水性紫外光木器涂料,经检测,水性UV涂装性能上大大得到改善,气味比普通UV涂料低、硬度比水性木器涂料高、表面效果与施工方法得到有效的改善,解决了水性木器、UV光固化涂料在喷涂技术领域遇到的技术瓶颈。