Preparation of photodegradable polypropylene/clay composites based on nanoscaled TiO2 immobilized organoclay

Photodegradable polypropylene (PP) composites were prepared via melting blending using PP and titanium dioxide (TiO₂) immobilized organically modified montmorillonite (organoclay). TiO₂ immobilized organoclay (TiO₂‐OMT) was synthesized by immobilizing anatase TiO₂ nanoparticles on organically modified clay via sol–gel method. The structure and morphology of TiO₂‐OMT were characterized by XRD and scanning electron microscope (SEM), which showed that anatase TiO₂ nanoparticles with the size range of 8–12 nm were uniformly immobilized on the surface of organoclay layers. Diffuse reflection UV–vis spectra revealed TiO₂‐OMT had similar absorbance characters to that of commercial photocatalyst, Degussa P25. The solid‐phase photocatalytic degradation of PP/TiO₂‐OMT composites was investigated by FTIR, DSC, GPC and SEM. The results indicated that TiO₂‐OMT enhanced the photodegradation rate of PP under UV irradiation. This was due to that immobilization of TiO₂ nanoparticles on organoclay effectively avoided the formation of aggregation, and thereby increased the interface between PP and TiO₂ nanoparticles. After 300 h irradiation, the average molecular weight was reduced by two orders of magnitude. This work presented a promising method for preparation of environment‐friendly polymer nanocomposites. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers.     

Preparation of CdS/TiO2 nanotube arrays and the enhanced photocatalytic property

In this paper, a series of CdS/TiO₂ NTs have been synthesized by SILAR method. The as-prepared CdS/TiO₂ NTs have been analyzed by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive spectrometer (EDS), and ultraviolet–visible (UV–vis). And their photocatalytic activities have been investigated on the degradation of methylene blue under simulated solar light irradiation. XRD results indicate that TiO₂ NTs were anatase phase, CdS nanoparticles were hexagonal phase. FESEM results indicate that low deposition concentration can keep the nanotubular structures. UV–vis results indicate that CdS can be used to improve the absorbing capability of TiO₂ NTs for visible light, and the content of CdS affects the band gap. Photocatalytic results indicate that CdS nanoparticles are conducive to improve the photocatalytic efficiency of TiO₂ NTs, and the highest degradation rate can reach 93.8%. And the photocatalytic mechanism of CdS/TiO₂ NTs to methylene blue is also described.     

The optical properties of PVA/TiO2 composite nanofibers

The electrospun nanofibers emerge several advantages because of extremely high specific surface area and small pore size. This work studies the effect of PVA nanofibers diameter and nano‐sized TiO₂ on optical properties as reflectivity of light and color of a nanostructure assembly consisting polyvinyl alcohol and titanium dioxide (PVA/TiO₂) composite nanofibers prepared by electrospinning technique. The PVA/TiO₂ composite spinning solution was prepared through incorporation of TiO₂ nanoparticles as inorganic optical filler in polyvinyl alcohol (PVA) solution as an organic substrate using the ultrasonication method. The morphological and optical properties of collected composites nanofibers were highlighted using scanning electron microscopy (SEM) and reflective spectrophotometer (RS). The reflectance spectra indicated the less reflectance and lightness of composite with higher nanofiber diameter. Also, the reflectance and lightness of nanofibers decreased with increasing nano‐TiO₂ concentration. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis and photocatalytic performance of PVA/TiO2/graphene‐MWCNT nanocomposites for dye removal

TiO₂/graphene‐MWCNT nanocomposite was prepared using solvothermal reaction for the effective distribution of TiO₂ nanoparticles on carbonaceous materials. TiO₂/graphene‐MWCNT nanocomposite was immobilized in poly(vinyl alcohol) (PVA) matrix for a convenient recovery after wastewater purification. MWCNT was incorporated in a nanocomposite not only to prevent the restacking of graphene but also to increase the electron transfer from TiO₂. The detailed characterization of the nanocomposite was performed using SEM, EDX, XRD, XPS, and FTIR. The photocatalytic performance of PVA/TiO₂/graphene‐MWCNT nanocomposite was investigated by UV spectroscopy on the basis of degradation of organic pollutants. PVA/TiO₂/graphene‐MWCNT nanocomposite showed improved photocatalytic decomposition of more than 70% of residual dye left in case of using PVA/TiO₂/graphene nanocomposite due to the improved electron transfer and the higher adsorption of organic pollutants. PVA/TiO₂/graphene‐MWCNT nanocomposite was suitable as a promising material for the recyclable photocatalytic wastewater purification system. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40715.     

Structural stability of photodegradable poly(l-lactic acid)/PE/TiO2 nanocomposites through TiO2 nanospheres and TiO2 nanotubes incorporation

Photodegradation of PLA/PE, PLA/PE/TiO₂ nanospheres and PLA/PE/TiO₂ nanotubes was obtained under simulated sunlight. The nanocomposites were analyzed by infrared spectroscopy, scanning electron microscopy and tensile-deformation measurements. TiO₂ nanospheres and TiO₂ nanotubes were found to present different effects on the crystallinity of PLA and a straight correlation between structural organization and photostability was observed. According to the results, TiO₂ promotes the degradation of PLA and PE, affecting the organizational level of the polymers. By adding TiO₂ nanoparticles to the PLA/PE films, vibration modes characteristic of degradation products were promptly observed and the lifetime of the polymer decreased when compared to the PLA/PE without TiO₂ nanoparticles. Mechanical measurements showed an improvement of the mechanical properties when adding the TiO₂ nanoparticles.     

Ag@AgCl‐TiO2/organic rectorite/quaternized chitosan microspheres: An efficient and environmental photocatalyst

A plasmonic composite, Ag@AgCl‐TiO₂/OREC, was prepared by sol–gel combing calcination technique, precipitation, and photoreduction method. Then, Ag@AgCl‐TiO₂/OREC/QCS composite microspheres were fabricated by an emulsification/chemical crosslinking method using quaternized chitosan and Ag@AgCl‐TiO₂/OREC as scaffolds materials, potassium persulphate as initiator and N,N′‐methylenebisacrylamide as crosslinker. The resulting materials were characterized by Fourier transform infrared spectrometer (FTIR), X‐ray diffraction (XRD), UV‐visible diffused reflectance spectra (UV–vis DRS), and scanning electron microscopy (SEM). SEM showed that the Ag@AgCl‐TiO₂/OREC/QCS composite microspheres had loose, rough surface, and spherical shape, with an average diameter of 15–45 μm. The Ag@AgCl‐TiO₂/OREC/QCS composite microspheres present good adsorption–photocatalytic activities in the degradation of methylene orange (MO) and 92.1% MO was degraded after irradiation for 180 min. The high photocatalysis activity was attributed to the combined results of the relative high adsorption capacity, loose structure, and the surface plasmon resonance of silver nanoparticles formed on the surface of AgCl. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44601.     

The Assembly of TiO2 Nanoparticles into Micrometer‐Sized Structures,Photocatalytically Active Under UV and Vis Light

Micrometer‐sized structures consisting of TiO₂ nanoparticles were prepared using the sol–gel technique in combination with the structure‐directing agent triethanolamine (TEA). The interaction of the TEA with the hydrolyzed sol–gel products led to the formation of TEA titanate complexes, which then enabled the assembly of sol–gel‐precipitated nanosized powders. A subsequent thermal treatment of these powders resulted in the formation of micrometer‐sized structures consisting of TiO₂ anatase and rutile nanoparticles. To characterize the prepared powders, FTIR spectroscopy, XRD analysis, the Brunauer‐Emmett‐Teller method (s_BET), UV–Vis spectrometry and electron microscopy (FE‐SEM, and TEM) were employed. The photocatalytic degradation of the azo dye known as methylene blue was monitored under UV and Vis irradiation and showed that the micrometer‐sized structures consisting of TiO₂ nanoparticles exhibited a similar photocatalytic activity to submicrometer‐sized structures consisting of TiO₂ nanoparticles prepared without TEA.     

Electrochemical synthesis and in situ spectroelectrochemistry of conducting polymer nanocomposites. I. polyaniline/TiO2, polyaniline/ZnO,and polyaniline/TiO2+ZnO

The polyaniline (PAn), polyaniline/titanium dioxide (PAn/TiO₂), polyaniline/zinc oxide (PAn/ZnO), and a novel conducting polymer nanocomposites, polyaniline/titanium dioxide + zinc oxide (PAn/TiO₂+ZnO), were synthesized by in situ electropolymerization and potential cycling on gold electrode. The PAn and nanocomposite films were characterized by cyclic voltammetry, Fourier transform infra‐red (FTIR) spectroscopy, in situ resistivity measurements, in situ UV–Visible, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The differences between cathodic and anodic peaks of three redox couples were obtained for PAn and polymeric nanocomposite films. During cathodic and anodic scans, the shift of potential was observed for polymer nanocomposite films. The characteristic FTIR peaks of PAn were found to shift to lower wavelengthsin polymer nanocomposite films. These observed effects have been attributed to interaction of TiO₂, ZnO, and TiO₂+ZnO particles with PAn molecular chains. Significant differences from in situ resistivity of PAn and nanocomposite films were obtained. The resistance of PAn/TiO₂, PAn/ZnO, and PAn/TiO₂+ZnO films were found to be smaller than the PAn film. The in situ UV–Visible spectra for Pan and polymer nanocomposite films were studied. The results show the intermediate spectroscopic properties between PAn and polymer nanocomposite films. The morphological analyses of PAn and nanocomposite films have been investigated. The nanocomposites SEM and TEM micrographs suggest that the inorganic semiconductor particles were incorporated in organic conducting polymer, which consequently modifies the morphology of the films significantly. POLYM. COMPOS., 35:351–363, 2014. © 2013 Society of Plastics Engineers     

Fabrication of CdS and CuWO4 modified TiO2 nanoparticles and its photocatalytic activity under visible light irradiation

CdS and CuWO₄ modified TiO₂ nanoparticles (CdS–CuWO₄-TiO₂) were prepared by the chemical impregnation method. The as-prepared nanoparticles were characterized using UV–visible-diffuse reflectance spectroscopy (UV–vis-DRS), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS) and B.E.T. surface area analysis techniques. The photocatalytic activity was evaluated based on the degradation of a dye (eosin-Y) and inactivation of a bacterium (Pseudomonas aeruginosa). The results revealed that CdS–CuWO₄-TiO₂ showed high photocatalytic activity over CdS-TiO₂, CuWO₄-TiO₂ and TiO₂. Moreover the reusability and stability of the photocatalyst for the degradation of eosin-Y was also studied.     

Preparation of aerochitin‐TiO2 composite for efficient photocatalytic degradation of methylene blue

An aerochitin–titania (TiO₂) composite was successfully synthesized and characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, thermogravimetric analysis, field emission scanning electron microscopy, and N₂ adsorption isotherms. The photocatalytic activity of the composite was investigated on the degradation of the model organic pollutant, methylene blue (MB) dye, under UV irradiation. The aerochitin–TiO₂ composite showed excellent adsorptive and photocatalytic activity with a degradation degree of 98% for MB. The first‐order rate constants for the photodegradation MB by TiO₂ nanoparticles and aerochitin–TiO₂ composite were found to be (3.49 ± 0.04) × 10^?3 and (1.82 ± 0.02) × 10^?2 min^?1. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45908.     

Photosensitive antibacterial and cytotoxicity performances of a TiO2/carboxymethyl chitosan/poly(vinyl alcohol) nanocomposite hydrogel by in situ radiation construction

Nano‐TiO₂/carboxymethyl chitosan (CMCS)/poly(vinyl alcohol) (PVA) ternary nanocomposite hydrogels were prepared by freezing–thawing cycles and electron‐beam radiation with PVA, CMCS, and nano‐TiO₂ as raw materials. The presence of nano‐TiO₂ nanoparticles in the composite hydrogels was confirmed by thermogravimetry, Fourier transform infrared spectroscopy, and X‐ray powder diffraction. Field emission scanning electron microscopy images also illustrated that the TiO₂/CMCS/PVA hydrogel exhibited a porous and relatively regular three‐dimensional network structure; at the same time, there was the presence of embedded nano‐TiO₂ throughout the hydrogel matrix. In addition, the nano‐TiO₂/CMCS/PVA composite hydrogels displayed significant antibacterial activity with Escherichia coli and Staphylococcus aureus as bacterial models. The antibacterial activity was demonstrated by the antibacterial circle method, plate count method, and cell density method. Also, with the Alamar Blue assay, the cytotoxicity of the composite hydrogel materials to L929 cells was studied. The results suggest that these materials had no obvious cytotoxicity. Thus, we may have developed a novel, good biocompatibility hydrogel with inherent photosensitive antibacterial activity with great potential for applications in the fields of cosmetics, medical dressings, and environmental protection. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44150.     

Preparation of Ag nanoparticles loaded TiO2 nanoplate arrays on activated carbon fibers with enhanced photocatalytic activity

Ag loaded TiO₂ nanoplate array which grew on activated carbon fiber (ACF) was prepared in the present work. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV–Vis diffuse reflectance spectra (DRS). The photocatalytic degradation of methylene blue (MB) was used to investigate the activity of the synthesized samples. Under both UV and visible light irradiation, the Ag loaded samples showed enhanced photocatalytic activity. Besides, the effect of the deposition dosage of Ag nanoparticles on the photocatalytic activity was also investigated. Under UV light irradiation, the Ag nanoparticles acted as electron traps, which enhanced electron–hole separation efficiency of TiO₂. Under visible light irradiation, the Ag nanoparticles showed surface plasmon resonance, which induced the visible light responsive photocatalytic activity for the obtained samples.     

Synthesis of three-dimensional ordered macroporous TiO2, Gd/TiO2 and their photocatalytic activity

In this paper, three-dimensional ordered macroporous (3DOM) TiO₂ and Gd/TiO₂ materials were synthesized by colloidal crystal templating process. The obtained samples were analyzed by field-emission scanning electron microscope, transmission electron microscopy, X-ray diffraction, diffuse reflectance spectra and Brunauer–Emmett–Teller method. The photocatalytic activity of various samples was evaluated by degradation of methyl orange in aqueous solution under UV and visible light irradiation. At the same time, Degussa P25 (a commercial Titania) powders were used for comparison. The results indicated that 3DOM Gd/TiO₂ samples showed a significant shift in the onset absorption towards the longer wavelength compare to pure 3DOM TiO₂, and displayed excellent photocatalytic activity under both UV and visible light irradiation.     

Structural and ultraviolet‐protective properties of nano‐TiO2‐doped polypropylene filaments

Textiles, with appropriate light absorbers and suitable finishing methods, can be used as ultraviolet (UV) protection materials. In this study, we investigated the effects of nano‐TiO₂ particles on the UV‐protective and structural properties of polypropylene (PP) textile filaments. Master batches of PP/TiO₂ nanoparticles were prepared by melt compounding before spinning, and filaments incorporating 0.3, 1, and 3% TiO₂ nanoparticles were spun in a pilot melt‐spinning machine. The structural properties of the nanocomposite fibers were analyzed with scanning electron microscopy, X‐ray diffractometry, differential scanning calorimetry, and tensile tests. The UV‐protection factor was determined to evaluate the UV‐protective properties of the filaments. In conclusion, although the structure and mechanical properties of the nanocomposite filaments were slightly affected by the addition of nano‐TiO₂, the UV‐protective properties of the PP filaments improved after treatment with nano‐TiO₂, and the nanocomposite filaments exhibited excellent UV protection. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation and characterization of cerium‐doped titanium dioxide/ultrahigh‐molecular‐weight polyethylene porous composites with excellent photocatalytic activity

Porous ultrahigh‐molecular‐weight polyethylene (UHMWPE)‐based composites filled with surface‐modified Ce‐doped TiO₂ nanoparticles (Ce–TiO₂/UHMWPE) were prepared by template dissolution. The composites were characterized by Fourier transform infrared spectroscopy, ultraviolet (UV)–visible spectroscopy, diffuse reflectance spectra, and scanning electron microscopy); the photocatalytic activity was also evaluated by the decomposition of methyl orange under UV exposure. The results demonstrate that the severe aggregation of Ce–TiO₂ nanoparticles could be reduced by surface modification via a silane coupling agent (KH570). The Ce–TiO₂/UHMWPE porous composites exhibited a uniform pore size. Doping with Ce⁴⁺ effectively extended the spectral response from the UV to the visible region and enhanced the surface hydroxyl groups of the TiO₂ attached to the matrix. With a degradation rate of 85.3%, the 1.5 vol % Ce–TiO₂/UHMWPE sample showed the best photocatalytic activity. The excellent permeability of the porous composites is encouraging for their possible use in wastewater treatment. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Preparation and characterization of a novel activated carbon‐supported N‐doped visible light response photocatalyst (TiO2−xNy/AC)

A photocatalyst, TiO_2?xN_y/AC (activated carbon (AC) supported N‐doped TiO₂), highly active in both the Vis and UV range, was prepared by calcination of the TiO₂ precursor prepared by acid‐catalyzed hydrolysis in an ammonia atmosphere. The powders were characterized by diffuse reflectance spectroscopy, scanning electron microscopy, X‐ray diffraction, N₂ adsorption, Fourier transform infrared spectroscopy and phenol degradation. The doped N in the TiO₂ crystal lattice creates an electron‐occupied intra‐band gap allowing electron‐hole pair generation under Vis irradiation (500–560 nm). The TiO_2?xN_y/AC exhibited high levels of activity and the same activity trends for phenol degradation under both Vis and UV irradiation: TiO_2?xN_y/AC calcined at 500 °C for 4 h exhibited the highest activity. The band‐gap level newly formed by doped N can act as a center for the photo‐generated holes and is beneficial for the UV activity enhancement. The performance of the prepared TiO_2?xN_y/AC photocatalyst revealed its practical potential in the field of solar photocatalytic degradation of aqueous contaminants. Copyright © 2007 Society of Chemical Industry     

Preparation,characterization, and photocatalytic degradation properties of polyacrylamide/calcium alginate/TiO2 composite film

Titanium dioxide (TiO₂) nanoparticles were dispersed in the sodium alginate and acrylamide aqueous solution to prepare the casting solution. The casting solution was spread on a glass plate by a glass rod enlaced with brass wires to control the thickness of the film. Then polyacrylamide/calcium alginate/TiO₂ (PAM/CA/T) composite film was obtained after UV irradiation and crosslinking by CaCl₂. The PAM/CA/T film was characterized by scanning electron microscopy and transmission electron microscope. The mechanical properties of the films were tested in wet form and the results showed that PAM/CA/T film had good strength and toughness. PAM/CA/T films did not rupture after swelling in 5.0 wt% NaCl solution and still had good mechanical properties. The PAM/CA/T hydrogel film provided a suitable carrier for TiO₂ in the photocatalytic degradation of dyes and the degradation rate of PAM/CA/T‐30 for methyl orange reached 80.8%. The PAM/CA/T film had good reusability and could degrade dyes in a high concentration of NaCl solution. POLYM. COMPOS. 37:1292–1301, 2016. © 2014 Society of Plastics Engineers     

Effect of calcination temperature of TiO2 on the crystallinity and the permittivity of PVDF‐TrFE/TiO2 composites

Composite membranes of poly(vinylidene‐trifluoroethylene)/titanium dioxide (PVDF‐TrFE/TiO₂) were prepared by the solution cast method. The crystallization behavior and dielectric properties of the composites with TiO₂ calcined at different temperatures were studied. Transmission electron microscopy and X‐ray diffraction (XRD) results showed that the TiO₂ nanoparticles calcined at different temperatures were well dispersed in the polymer matrix and did not affect the structure of the PVDF‐TrFE matrix. XRD and differential scanning calorimeter measurements showed that the crystallinity of PVDF‐TrFE/TiO₂ composites increased as the addition of TiO₂ with different calcination temperatures. The dielectric property testing showed that the permittivity of PVDF‐TrFE/TiO₂ membrane increased rapidly with the increase of TiO₂ content and the calcination temperature of TiO₂ at constant TiO₂ content, but the dielectric loss did not change much. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Solid‐state synthesis and characterization of polyaniline/nano‐TiO2 composite

Polyaniline/nano‐TiO₂ composites with the content of nano‐TiO₂ varying from 6.2 wt % to 24.1 wt % were prepared by using solid‐state synthesis method at room temperature. The structure and morphology of the composites were characterized by the Fourier transform infrared (FTIR) spectra, ultraviolet‐visible (UV–vis) absorption spectra, X‐ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The electrochemical performances of the composites were investigated by galvanostatic charge–discharge measurement, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The results from FTIR and UV–vis spectra showed that the composites displayed higher oxidation and doping degree than pure PANI. The XRD and morphological studies revealed that the inclusion of nano‐TiO₂ particles hampered the crystallization of PANI chains in composites, and the composites exhibited mixed particles from free PANI particles and the nano‐TiO₂ entrapped PANI particles. The galvanostatic charge–discharge measurements indicated that the PANI/nano‐TiO₂ composites had higher specific capacitances than PANI. The composite with 6.2 wt % TiO₂ had the highest specific capacitance among the composites. The further electrochemical tests on the composite electrode with 6.2 wt % TiO₂ showed that the composite displayed an ideal capacitive behavior and good rate ability. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis and characterization of interpenetrating polymer network based on sodium alginate and methacrylic acid and potential application for immobilization of TiO2 nanoparticles

An interpenetrating polymer network (IPN) based on the sodium alginate (A) and partially neutralized poly(methacrylic acid) (MAA) was prepared by free radical polymerization followed by additional cross‐linking of sodium alginate with calcium ions. Obtained material (A/MAA IPN) was characterized by FTIR spectroscopy, thermogravimetric analysis, scanning electron microscopy, and rheological measurements. Swelling behavior of synthetized IPN has been also investigated. TiO₂ nanoparticles (TiO₂ NPs) were immobilized onto A/MAA IPN by dip‐coating method and obtained TiO₂/IPN nanocomposite was used for removal of the methylene blue (MB) from aqueous solution. The photodegradation (under illumination) and sorption (in the dark) processes for dye removal were monitored through decrease of dye concentration in the solution by UV/VIS spectrometer. The TiO₂/IPN nanocomposite sorbed approximately 93% of the MB from a 10 mg L^?1 MB solution in the dark, but no degradation occurred. Likewise, more than 93% of dye was removed after 8 h of illumination. However, after 24 h of illumination, the samples were discolored indicating that dye molecules were successfully degraded. Thus, the TiO₂/IPN nanocomposite could be utilized in the photodegradation–sorption process for the abatement of pollutants in water. POLYM. ENG. SCI., 55:2511–2518, 2015. © 2015 Society of Plastics Engineers