Preparation of luminescent polyethylene plastic composite nano-reinforced with glass fibers

Electrospun glass nanofibers (EGNFs) were prepared to reinforce polyethylene (PE) plastic waste towards the development of photochromic anti-counterfeiting patterns and long-persistent photoluminescent materials, such as smart windows and concrete. By physical integration of lanthanide-doped aluminate (LdA) nanoparticles (NPs) into polyethylene plastic reinforced with EGNFs, a transparent lanthanide-doped aluminate nanoparticles (LdANPs)/EGNFs@PE sheet was produced. The colorless EGNFs@PE hybrids became green under ultraviolet (UV) rays and greenish-yellow in a darkened room as proved by CIE Lab and photoluminescence analysis. In the luminescent LdANPs/EGNFs@PE hybrids, the identified photochromism was promptly reversed at low concentrations of LdANPs to designate fluorescence emission. Photoluminescence was maintained with slow reversibility for the high phosphor concentrations to designate afterglow emission. LdANPs exhibit diameters of 5–12 nm, whereas glass nanofibers have diameters of 70–120 nm. The morphologies of LdANPs/EGNFs@PE substrates were studied by energy-dispersive x-ray spectroscopy (EDX), scanning electron microscopy (SEM), and x-ray fluorescence (XRF). The mechanical properties of the prepared polyethylene plastic were enhanced by reinforcement with glass nanofibers as a roughening agent. The photoluminescent substrates showed markedly improved scratch resistance in comparison to LdANPs-free EGNFs@PE substrate. The obtained luminescence spectra displayed an emission band at 519 nm upon excitation at 365 nm. The results demonstrated that the luminous plastic has improved hydrophobicity and UV shielding upon increasing the LdANPs content.     

Preparation of transparent photoluminescence plastic concrete integrated with lanthanide aluminate

A simple strategy was presented for potential industrial preparation of persistent afterglow lightweight plastic concrete toward smart hard surfaces. Rare-earth activated aluminate (REA) pigment nanoparticles (NPs) were integrated into plastic bar. The transparency of the prepared plastic bar can be achieved by consistent distribution of REA NPs in the plastic fluid. Unsaturated polyester resin (bulk material) was mixed with silica nanoparticles (filler) and REA NPs (luminescent agent) using methyl ethyl ketone peroxide as hardener. The curing process was accomplished for a few minutes at room temperature. The diameters of REA NPs were reported in the range of 6–11 nm. The phosphor-concrete composite can be industrially applied onto a variety of hard surfaces. The photoluminescent plastic concrete showed an emission band at 515 nm upon excitation at 372 nm. Persistent photoluminescence was detected for pigment concentrations higher than 1%, whereas fluorescence emission was monitored for pigment concentrations equal to 1%. Photochromism was observed for the prepared plastic concrete as different colors were detected under different light conditions, including colorless under daytime light, green underneath UV rays, and greenish-yellow under darkness as proved by luminescence spectra and CIE Lab parameters. The static contact angle measurements proved good superhydrophobic activity. An improved UV protection and photostability were detected. The photoluminescent hard composite concrete displayed highly durability and reversible persistent afterglow emission. The morphology, elemental composition and hardness features of the prepared plastic concrete were investigated.     

Preparation of dual mode encoding photochromic electrospun glass nanofibers for anticounterfeiting applications

Photochromism has shown to be a promising tool for improving the authenticity of commercially available products. Additionally, improving the engineering process of authentication patterns has been crucial to offer mechanically reliable anticounterfeiting nanofibers. Herein, the electrospinning technology was applied to develop mechanically reliable and photoluminescent silicon dioxide-based electrospun glass nanofibers (80–110 nm) embedded with lanthanide-activated aluminate (LA) nanoparticles (NPs; 1–2 nm) for anticounterfeiting purposes. The produced nanocomposite films exhibited photochromism from colorless in visible spectrum to green under ultraviolet irradiation. The nanofibrous film transparency was maintained by presenting the strontium aluminate pigment as nano-scaled particles, which improves its distribution and prevents the formation of aggregates in the electrospun glass nanofibrous bulk. After being excited at 365 nm, the nanofibers made of phosphor@glass (LANPs@GLS) displayed an emission band at 519 nm. Increases in the pigment ratio enhanced the hydrophobicity of the LANPs@GLS nanofibers without altering their intrinsic characteristics. The LANPs@GLS films exhibited fast and reversible photochromism without fatigue when activated by UV light. Transparency and flexibility were shown by the nanofibrous mats. The proposed technique is reliable for making a wide range of anticounterfeiting materials.     

Synthesis and corrosion protection aspects of poly(<Emphasis Type="Italic">o</Emphasis>-toluidine)/CdO nanoparticle composite coatings on mild steel

This study examines the possibility of using poly(o-toluidine)/CdO (POT-CdO) nanoparticle composite coating for corrosion protection of mild steel in chloride environment. The POT-CdO nanoparticle composite coating was synthesized on mild steel from aqueous tartrate solution containing CdO-nanoparticles (size ~18 nm) by using cyclic voltammetry. These coatings were characterized by cyclic voltammetry, UV–Visible absorption spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray diffraction measurements. The corrosion protection aspects of the resulting POT-CdO nanocomposite structure were investigated in aqueous 3% NaCl solution by potentiodynamic polarization technique and electrochemical impedance spectroscopy. The results of these investigations reveal that the POT-CdO nanoparticle composite acts as a protective coating on mild steel and reduces the corrosion rate of mild steel almost by factor of 70.     

Chemical synthesis of TiO2 nanoparticles and their inclusion in Ni–P electroless coatings

The work addresses the preparation of Ni3P3TiO₂ nanocomposite coatings on mild steel substrate by the electroless technique. Nanosized TiO₂ particles were first synthesized by the precipitation method and then were codeposited (4 g/l) into the Ni3P matrix using alkaline hypophosphite reduced EL bath. The surface morphology, particle size, elemental composition and phase analysis of as-synthesized TiO₂ nanoparticles and the coatings were characterized by field emission scanning electron microscopy (FESEM), energy-dispersive analysis of X-ray (EDAX) and X-ray diffraction (XRD). Coatings with 20 µm thickness were heat treated at 400 °C for 1 h in argon atmosphere. The morphology, microhardness, wear resistance and friction coefficient characteristics (ball on disc) of electroless Ni3P3TiO₂ nanocomposite coatings were determined and compared with Ni3P coatings. The results show that as-synthesized TiO₂ nanoparticles are spherical in shape with a size of about12 nm. After heat treatment, the microhardness and wear resistance of the coatings are improved significantly. Superior microhardness and wear resistance are observed for Ni3P3TiO₂ nanocomposite coatings over Ni3P coatings.     

Effect of the incorporation of montmorillonite-layered double hydroxide nanoclays on the corrosion protection of epoxy coatings

A series of layered double hydroxide (LDH)/montmorillonite (MMT) nanocomposite coating, LDH nanocomposite coating, and MMT nanocomposite coating were successfully prepared. The nanocomposite materials were characterized by X-ray diffraction and scanning electron microscopy (SEM). To understand the effect of MMT and LDH on the corrosion inhibition performance of epoxy resin coatings immersed in 3.5 wt% saline solution at 90°C, electrochemical impedance spectroscopy and an autoclave test were performed on epoxy resin; epoxy resin blended with LDH, MMT, and LDH + MMT (LM) coatings painted on Q345 steel. The metal/coating interfaces were observed by SEM and energy-dispersive spectroscopy. Results showed that addition of LDH and MMT improved the protection properties of the epoxy resin coatings. The corrosion protection of the LM nanocomposite coating was superior to that of the other coatings. This finding can be attributed to the ionic selectivity and barrier effect of MMT and LDH nanoclay platelets dispersed within the composite coatings.     

Investigation of corrosion protection properties of an epoxy nanocomposite loaded with polysiloxane surface modified nanosilica particles on the steel substrate

In this study, it has been aimed to investigate the corrosion protection properties of an epoxy/polyamide coating loaded with different concentrations (ranged from 3 to 6% (w/w)) of the polysiloxane surface modified silica nanoparticles (nano-SiO₂). The nanocomposites were applied on the steel substrates. Field emission scanning electron microscope (FE-SEM) and UV–vis techniques were utilized in order to investigate the nanoparticles dispersion in the coating matrix. The effects of addition of nanoparticles on the corrosion resistance of the coating were studied by an electrochemical impedance spectroscopy (EIS) and salt spray test. The coating surface degradation was studied by optical microscope and Fourier transform infrared radiation (FT-IR) spectroscopy. Results obtained from UV–vis and FE-SEM analyses revealed proper and uniform distribution of surface modified nanoparticles in the epoxy coating matrix. It was shown that the coating corrosion protection properties were significantly enhanced in the presence of 5 wt% silica nanoparticles. Less degradation occurred on the surface of the coatings loaded with 5 wt% nanoparticles.     

Self-healing and anticorrosive properties of Ce(III)/Ce(IV) in nanoclay–epoxy coatings

The self-healing and anticorrosion effects of cerium nitrate in epoxy–clay nanocomposite coatings systems were studied. Different amounts of cerium (III) were added to epoxy–montmorillonite clay composites and the nanocomposite coatings were prepared and applied on cold rolled steel panels. Ultrasonication was applied to disperse the nanoclay into the epoxy cerium nitrate composition. Electrochemical impedance spectroscopy (EIS) was used to study the self-healing and anticorrosion behaviors of the coatings. The structure of the dry coating and the protective mechanism of the pigments in the coating were investigated by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) analysis and field emission electron microscopy (FESEM). Transmission electron microscopy (TEM) illustrated the separation of clay layers which interacted with the epoxy resin. Electrochemical impedance data indicated that the epoxy cerium (III)–montmorillonite nanocomposite coatings were superior to the epoxy coatings in corrosion protection properties. The self-healing behavior of such coatings was due to the presence of cerium nitrate that could be released at the defects within the coating and hindered the corrosion reactions at the defective sites. It was shown that the best corrosion protection was achieved with nanocomposite coatings containing 4 wt% clay and 2 wt% cerium nitrate.     

SiAlON–epoxy nanocomposite coatings: Corrosion and wear behavior

In this study, epoxy powder as a matrix was combined with different contents of silicon–aluminum–oxygen–nitrogen (SiAlON) nanoparticles using a planetary ball mill. Pure epoxy and nanocomposite powders were applied on the surface of plain carbon steel components by the electrostatic spraying method. Curing of the coatings was done in an oven or microwave for the appropriate time. The coating structure and morphology of the SiAlON nanoparticles were studied by scanning electron microscopy and transmission electron microscopy, respectively. The corrosion properties of the coatings were assessed by immersion, Tafel polarization, and electrochemical impedance spectroscopy tests in 3.5% NaCl solution. The results show that addition of 10 wt % SiAlON nanoparticles markedly increases the corrosion resistance of epoxy coatings. Thus, it can be inferred that the corrosion rate of these coatings is 15 to 18 times lower than that of pure epoxy samples and 8 to 11 times lower than coatings with 20 wt % SiAlON. The higher corrosion resistance of nanocomposite coatings can be attributed to the barrier properties of SiAlON nanoparticles. The tribological performance of the coatings was studied with the pin‐on‐disk test. The results of wear testing show that the samples containing 10 wt % SiAlON provide about five times more wear resistance than pure ones and about two times more than coatings with 20 wt % SiAlON. However, the coefficient of friction for nanocomposite coatings is reduced about 50% compared to the pure sample. Also, the curing process in either regime (oven or microwave) has the same effect on the corrosion and wear properties, and the coatings are completely crosslinked. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43855.     

Reinforcement of styrene-acrylonitrile polymer bulk with glass nanofibers to introduce photoluminescent bricks

Transparent and mechanically reliable plastic was developed by reinforcing styrene-acrylonitrile polymer (SAP) with electrospun glass nanofibers (EGN). The physical inclusion of strontium aluminate nanoparticles (SAN) produced long-persistent photoluminescent and photochromic EGN@SAP bricks or smart windows. EGN were fabricated by electrospinning technique and incorporated as a toughening mediator into styrene-acrylonitrile plastic to boost its mechanical properties. Transparency of EGN@SAP with the capacity to shift to green under ultraviolet (UV) illumination was verified using photoluminescence analysis and CIE Lab parameters. EGN@SAP with low content of SAN exhibited immediate reversibility of the photochromic feature, proving fluorescence emission. Afterglow emission from EGN@SAP embedded with high concentration of SAN persisted for longer time and was less easily reversed. After excitation at 365 nm, the emission peaked at 519 nm. Increasing the SAN content resulted in improved hydrophobicity and UV protection. Diameter measurements of SAN (6–14 nm) and EGN (75–300 nm) were taken utilizing transmission electron microscopy and scanning electron microscopy, respectively. EGN and EGN@SAP bricks were analyzed for their morphological characteristics using a variety of analytical techniques. The scratch resistance of EGN@SAP bricks containing SAN was enhanced in comparison to SAN-free EGN@SAP bricks.     

Synthesis of nanocomposite polymers by UV-radiation curing

Clay-based nanocomposite polymers have been synthesized by photoinitiated crosslinking polymerization of acrylate and epoxy functionalized oligomers. The solvent-free resin containing a small amount (3 wt%) of organophilic clay was cured within seconds upon UV irradiation at ambient temperature. The polymerization reaction was followed by infrared spectroscopy and shown to proceed at a great extent in thick samples (2 mm), due to the higher exotherm and the resulting rise in temperature. The organoclay was shown to have no slowing down effect on the photopolymerization of both acrylate and epoxy resins. The addition of clay nanoparticles was found to reduce the gloss of UV-cured coatings due to an enhanced surface roughness. The viscoelastic and tensile properties of the nanocomposite photopolymer were comparable to those of the neat UV-cured polymer, while their resistance to moisture was significantly increased.     

Preparation of PANI/epoxy/Zn nanocomposite using Zn nanoparticles and epoxy resin as additives and investigation of its corrosion protection behavior on iron

Conducting polyaniline, zinc and epoxy resin solely have anticorrosive properties by different mechanisms on metallic substrates. In this work the triple hybrid of PANI/epoxy/Zn nanocomposite was prepared as a thin layer coating (70 ± 5 μm) on iron coupons and its anticorrosion performance was investigated in HCl (0.1 M) as corrosive solution. Epoxy resin and zinc nanoparticles were applied as additives in the PANI matrix to improve the mechanical properties of PANI coating and investigate their synergetic effects on the anticorrosion performance of PANI coating. At first PANI/Zn nanocomposite coatings with different Zn contents were prepared and the zinc content optimized so that the coating achieve the best anticorrosion performance. Accordingly the iron coupons coated by PANI/Zn coating having 4 wt% Zn content showed more noble open circuit potential and lower corrosion current values. Then epoxy resin was applied as additive to the optimized formulation of PANI/Zn coating in different weight percents (0–20 wt%) and the anticorrosion performance of the related PANI/epoxy/Zn triple hybrid nanocomposite coatings was evaluated. Results showed that the addition of epoxy resin causes to the decreasing of corrosion current of iron samples coated by PANI/epoxy/Zn nanocomposite. An optimum range of 3–7 wt% was obtained for the epoxy content in the composition of PANI/epoxy/Zn nanocomposite in which the coating exhibits the best anticorrosion performance. Iron metal coupon was elementally analyzed and the PANI/Zn and PANI/epoxy/Zn nanocomposites were characterized using Fourier Transform Infrared spectroscopy, X-ray diffraction patterns and Scanning Electron Microscopy techniques.     

Preparation and characterization of transparent ZnO/epoxy nanocomposites with high-UV shielding efficiency

Transparent ZnO/epoxy nanocomposites with high-UV shielding efficiency were reported in this paper. First, zinc oxide (ZnO) precursor was synthesized via the homogeneous precipitation method and ZnO nanoparticles were then made by calcination of the precursor at different temperature. The structural properties of the as-prepared ZnO nanoparticles were studied in detail using thermogravimetry (TGA), differential thermal analysis (DTA), X-ray diffractometer (XRD), Fourier transform infrared spectrometer (FT-IR) and transmission electron microscopy (TEM), respectively. Transparent ZnO/epoxy nanocomposites were subsequently prepared from transparent epoxy (EP-400) and as-prepared ZnO nanoparticles via in situ polymerization. Optical properties of ZnO/epoxy nanocomposites, namely visible light transparency and UV light shielding efficiency, were studied using an ultraviolet-visible (UV-vis) spectrophotometer. The optical properties of the as-obtained nanocomposites were shown to depend on ZnO particle size and content. The nanocomposite containing a very low content (0.07% in weight) of ZnO nanoparticles with an average particle size of 26.7 nm after calcination at 350 °C possessed the most optimal optical properties, namely high-visible light transparency and high-UV light shielding efficiency, that are desirable for many important applications.     

Structural,optical, morphological properties of silver doped cobalt oxide nanoparticles by microwave irradiation method

The synthesis of silver doped cobalt oxide nanoparticles by microwave-assisted method and their structural, optical, antibacterial activities are presented in this study. The doping concentrations were chosen as 5, 10, 15, and 20 wt percentages. The sample was undergone powder X-ray diffraction studies and the result shows the good crystalline nature of the sample. Also, the average crystallite size increases from 13.95 nm, 21.26 nm, 26.13 nm, and 28.35 nm with different doping concentrations. The transmission electron microscopy image shows cubic and spherical morphology. The optical properties were tested by UV–vis–NIR absorption spectrum. It indicates the decrease of band gap value. From the antibacterial activity studies, the 20 wt % Ag doped nanoparticles exhibit better activity.     

Ultra-rapid microwave-assisted synthesis of gallium doped zinc oxide for enhanced photocurrent generation

Ultra-rapid microwave-assisted hydrothermal synthesis was performed, zinc oxide nanoparticles were fabricated and doped with gallium. Different times (5, 15, and 30 min) and concentrations of doped Ga (1, 3, and 6%) were used to improve their characteristic properties. In addition, the relation between time/dopant was analyzed. The samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, and UV–Vis diffuse reflectance spectroscopy. Photoluminescence (PL) to verify number of defects. SEM analysis showed the formation of nanorods morphology even with a short synthesis time. The X-ray diffractograms and Raman spectra suggest the successful insertion of Ga into the ZnO lattice. The crystallite size obtained by doping was between 36 and 50 nm. The lattice parameters determined by the Rietveld refinement confirmed the formation of a wurtzite hexagonal structure. The band gap range found was 3.12–3.22 eV, which increases the potential of ZnO for optical applications. The presence of defects as result of doping was confirmed by PL. The microstructural changes of the material are enhanced by doping, which causes the photocurrent to increase from 0,002 to 0.012 mA/cm² in doped ZnO. The synthesis time and Ga doping facilitated the production of ZnO nanoparticles with improved properties.     

Investigation of corrosion protection performance of epoxy coatings modified by polyaniline/clay nanocomposites on steel surfaces

In this study, polyaniline (PANI) and polyaniline/clay nanocomposites were prepared via in situ oxidative polymerization. The morphology of nanocomposites structures was investigated by X-ray diffraction (XRD). The chemical structures of PANI and PANI/clay nanocomposites were examined via Fourier transform infrared (FT-IR) spectroscopy. Polyaniline-based pigments were introduced into epoxy paint and applied on steel substrates. The effect of clay addition and the type of clay cation, including Na⁺ in natural clay (MMT) and alkyl ammonium ions in organo-modified montmorillonite (OMMT), on the anticorrosion performance of epoxy-based coatings was investigated through electrochemical Tafel test, electrochemical impedance spectroscopy and immersion measurements in NaCl solution. The stability of the adhesion of the neat and modified epoxy coatings to the steel surface was also examined. The results indicated that introduction of PANI/OMMT nanocomposite into epoxy paint results in improved anticorrosion properties in comparison with PANI/MMT and neat PANI.     

Formulation and study of corrosion prevention behavior of epoxy cerium nitrate–montmorillonite nanocomposite coated carbon steel

Nanocomposite coatings which were applied on carbon steel panels based on epoxy cerium nitrate–montmorillonite (MMT) were synthesized and formulated. Nanoparticles were incorporated into epoxy resin by mechanical and sonication processes. The state of dispersion, dissolution, and incorporation were characterized by optical microscopy, sedimentation tests, X-ray diffraction, and transmission electron microscopy. To investigate anticorrosive properties of nanocomposite coatings, electrochemical impedance spectroscopy and salt spray tests were employed. The experimental results showed that epoxy cerium nitrate–MMT nanocomposite coatings were superior to the neat epoxy in corrosion protection effects. In addition, it was observed that the corrosion protection of nanocomposite coatings was improved as the clay loading was increased up to 4–2 wt% cerium nitrate.     

Optical and IR absorption of multilayer carbon nanowalls

Composition, optical and IR absorption spectroscopy, and complex characterization of multilayer carbon nanowall (CNW) coatings are studied. CNW coatings are made using multistep chemical vapor deposition (CVD) growth by DC discharge plasma enhancement method. Each of the growth steps leads to the formation of structurally and optically similar CNW layers with the average thickness of 1 μm. Optical properties of CNW films reveal no polarization dependence. The absorption of a single CNW layer with the average thickness of 1 μm has record values of 96–99% in the wavelength range from 0.4 to 10 μm, while the mirror reflection from the CNW films decreases steadily with the films thickness. We also demonstrate that the designed CNW films are stable with respect to water and alcohol environment.     

High Performance Organic Coatings of Polypyrrole Embedded with Manganese Iron Oxide Nanoparticles for Corrosion Protection of Conductive Copper Surface

Herein, we report the formation of organic composite coating consists of epoxy (EP) reinforced para toluene sulphonic acid (PTSA) doped polypyrrole (PPy)–manganese iron oxide (MnFe₂O₂) as an efficient corrosion inhibitor for copper substrates. The PTSA doped PPy:MnFe₂O₂ nanocomposite was synthesized via in situ polymerization of PPy in the presence of MnFe₂O₂ nanoparticles. Structural features of the prepared samples were characterized through scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), UV–visible spectroscopy and thermogravimetric analysis (TGA). The PTSA doped PPy:MnFe₂O₂ nanocomposite shows excellent conductivity and improved dielectric performance in comparison to pure PPy. The anti-corrosion performance of this organic composite coating was analyzed through Tafel polarization curves, open circuit potential (OCP), corrosion resistance, impedance spectroscopy and oxygen permeability barrier tests. The nanocomposite coating on copper substrate shows superior corrosion protection efficiency (99%) in comparison to pure epoxy (22%). Adhesion strength of the nanocomposite coating shows significant enhancement due to strong dispersions of MnFe₂O₂ nanoparticles in the host matrix. Owing to its improved conductivity, excellent anti-corrosion performance along with superior mechanical properties, the organic nanocomposite coating reported in this work can potentially be used to protect the conductive copper surfaces from harsh corrosive environments.

     

Capped inhibitor-loaded halloysite nanoclay-based self-healing silica coatings for corrosion protection of mild steel

The effect of polymeric nanocapsule capping in benzotriazole encapsulated into halloysite nanoclay (HNTs) dispersed into hybrid silica coatings was investigated for corrosion protection of mild steel. Optimization of the amount of inhibitor-loaded halloysite nanotubes with and without capping in the coating sol was carried out. The prepared formulations were dip-coated on mild steel substrates using dip-coater and then cured at 130 °C for 1 h. Surface morphology and elemental analysis of the nanoclay were studied using scanning electron microscopy and energy dispersive X-ray spectroscopy. X-ray diffraction and Fourier Transform Infrared spectroscopy analyses were carried out to confirm the encapsulation and capping of the halloysite nanoclay. The anti-corrosion and autonomic-healing properties of bare and coated substrates in 3.5 wt% NaCl solution were studied using electrochemical impedance spectroscopy, potentiodynamic polarization measurements and scanning vibrating electrode technique for varying exposure times. The coatings generated from the capped inhibitor-loaded HNTs dispersed sol-gel matrix was seen to provide higher corrosion resistance when compared to uncapped HNT based silica coatings. Electrochemical studies carried out for capped inhibitor-loaded HNT based coatings have shown an increase in charge transfer resistance to 10⁸ Ω cm² from 10⁶ Ω cm² of uncapped inhibitor-loaded HNT based coatings.