Poly(lactic acid)/titanium dioxide nanocomposite films: Influence of processing procedure on dispersion of titanium dioxide and photocatalytic activity (original) (raw)
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Biodegradable poly(L-lactic acid)/TiO2 nanocomposites: Thermal properties and degradation
Journal of Applied Polymer Science, 2012
Poly(L-lactic acid)-titanium dioxide nanocomposites (with various loadings of TiO 2 : 0.5, 1, 2, 5, and 10 wt %) were produced by solution casting method. The influence of TiO 2 on thermal properties and crystallinity of PLA was investigated by DSC and FTIR spectroscopy. The TiO 2 nano filler has no significant influence on the characteristic temperatures (T g , T c , and T m ), but has high impact on the crystallinity of these systems. The degree of crystallinity X c significantly increases for PLA nanocomposites loaded with up to 5 wt % of TiO 2 , while for 10 wt % load of TiO 2 it drops below X c of the pure resin. The degrada-tion of the prepared composites was evaluated hydrolytically in 1N NaOH, enzymatically in a-amylase solutions, and under UV irradiation. The catalytic effect of TiO 2 nano particles on the degradation processes under UV light exposure (k ¼ 365 nm) and hydrolytic degradation was confirmed with the increase of the filler content. The opposite effect was identified in enzymatic degradation experiments.
Photocatalytic properties of TiO2 sol–gel modified nanocomposite films
Ceramics International, 2011
TiO 2 nanocomposite films with different concentrations of TiO 2 MT-150A nanoparticles were immobilized on glass substrates using a dip coating process. The crystalline structure and surface chemical state of nanocomposite film properties were examined by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), respectively. The specific surface area and morphology of TiO 2 MT-150A nanoparticles were evaluated by the BET method and Field Emission Scanning Electron Microscopy (FE-SEM). The photocatalytic activities of films were evaluated by the methyl orange decoloring rate. XPS measurements showed that the oxygen amount (%) was related to the film composition. The composite film with 10 g/L MT-150A loading yielded the highest amount of surface oxygen (26.82%) and TiO 2 rutile showed the lowest amount of surface oxygen (13.67%) in the form of surface hydroxyl groups. The remaining oxygen was identified as lattice oxygen. In addition, the nanocomposite film with 10 g/L MT-150A loading yielded the highest photocatalytic activity. #
International Journal of Engineering & Technology
Synthetic polymer/TiO2 composite such as Polystyrene/TiO2 has become recent highly research materials due to its potential and significant application in various fields. we can tune the polymer and nanoparticles by different techniques such as change the materials concentration, Exposure of materials to laser radiation, Exposure of materials to laser radiation, especially in tuning the polystyrene/TiO2 composite energy band gap. In this review, several methods of preparation are briefly explored such as pan-milling, precipitation, melt compounding, dip-coating, solution cast, and sol-gel method. Some recent advancement that focuses on the two basic elements: polymer and TiO2 are also included especially discussing on photocatalytic degradation that introduces photon as manipulate parameter to tune the polymer/TiO2 composite energy band gap. Scanning electron microscope (SEM) analysis of various polymer/TiO2 (type n concentration) and Polystyrene/TiO2 (concentration and nanoparticles...
Study of thermomechanical and antibacterial properties of TiO2/Poly(lactic acid) nanocomposites
Materials Today: Proceedings, 2018
This study deals with the influence of titanium dioxide (TiO 2) nanoparticlesʼ incorporation via extrusion melt blending on various characteristics and properties of a low crystallinity poly(L-lactic acid) matrix. DSC and XRD analyses revealed that at 5 and 10 wt%, titania impeded the formation of crystalline domains. At 20 wt% titania, a small amount of crystallinity was developed. Improvement of the thermal stability and stiffness of the polymer was confirmed by TGA and tensile testing experiments. The investigation of antibacterial activity showed that the 20/80 w/w TiO 2 /PLLA nanocomposite presented the highest bactericidal efficiency in a UV-light and dark environment.
Poly(lactic acid) /TiO2 nanocomposites as alternative biocidal and antifungal materials
Materials Science and Engineering: C, 2015
Poly(lactic acid) (PLA) composites with titanium oxide (TiO 2)~10-nm nanoparticles were produced by the melting process and their main properties were evaluated. The nanoparticles are homogeneously dispersed in the matrix with a low degree of agglomeration, as seen by transmission electron microscopy (TEM). The crystallinity temperature increased~12% when 5 wt.% of TiO 2 was added, showing that the nanoparticles acted as nucleating agents this trend was confirmed by optical images. The elastic modulus increased~54% compared to neat PLA at 5 wt.% of nanoparticles. Despite these improvements, PLA/TiO 2 nanocomposites showed lower shear viscosity than neat PLA, possibly reflecting degradation of the polymer due to the particles. Regarding biocidal properties, after 2 h of contact the PLA/TiO 2 composites with 8 wt.% TiO 2 showed a reduction of Escherichia coli colonies of 82% under no UVA irradiation compared to pure PLA. This biocidal characteristic can be increased under UVA irradiation, with nanocomposites containing 8 wt.% TiO 2 killing 94% of the bacteria. The PLA/TiO 2 nanocomposites with 8 wt.% were also 99.99% effective against Aspergillus fumigatus under the UVA irradiation.
Journal of the Brazilian Chemical Society, 2022
In this study, a laccaic acid-modified TiO 2 photocatalyst (Lac-TiO 2) was prepared via an impregnation method with 0.50, 1.00, 2.50, and 5.00 wt.% laccaic acid. The products' physical properties were examined through X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM), X-ray photoemission spectroscopy (XPS), UV-Vis diffused reflectance spectroscopy (DRS), Fourier-transform infrared spectroscopy (FTIR), nitrogen adsorption/desorption, and photoluminescence (PL) spectroscopy. A possible photocatalytic mechanism was also proposed. XRD patterns revealed the anatase phase of TiO 2 and Lac-TiO 2 samples. High-magnification FE-SEM images showed that the TiO 2 and Lac-TiO 2 samples exhibited spherical-like structures. XPS results complementarily confirmed the presence of Ti, O, and C as the main elements of the Lac-TiO 2 samples. Interestingly, the DRS spectra of the Lac-TiO 2 samples extended into the visible region. FTIR spectra presented the characteristic bands of TiO 2 and hydroxyl groups on the TiO 2 surface. Instead of hydroxyl groups, the characteristic bands of laccaic acid were observed on the surface of the Lac-TiO 2 samples. The photocatalytic properties of the Lac-TiO 2 samples were evaluated in terms of methyl orange degradation under visible light irradiation. The Lac-TiO 2 samples showed higher photocatalytic performance than the TiO 2 sample.
Polymers
A mixed oxide of titania–silica oxides (TixSiy oxides) was successfully prepared via the sol–gel technique from our previous work. The use of TixSiy oxides to improve the mechanical properties, photocatalytic efficiency, antibacterial property, permeability tests, and biodegradability of polylactic acid (PLA) was demonstrated in this study. The influence of different types and contents of TixSiy oxides on crystallization behavior, mechanical properties, thermal properties, and morphological properties was presented. In addition, the effect of using TixSiy oxides as a filler in PLA composites on these properties was compared with the use of titanium dioxide (TiO2), silicon dioxide (SiO2), and TiO2SiO2. Among the prepared biocomposite films, the PLA/TixSiy films showed an improvement in the tensile strength and Young’s modulus (up to 5% and 31%, respectively) in comparison to neat PLA films. Photocatalytic efficiency to degrade methylene blue (MB), hydrolytic degradation, and in vitro...
Journal of Applied Polymer Science, 2014
In this study, low-density polyethylene (LDPE) nanocomposite films with two types of nanoparticles, TiO 2 (3 wt %) and Closite 20A (3 and 5 wt %), were prepared using a melt blow extrusion as an industrial method and their properties such as mechanical properties, water vapor, oxygen and carbon dioxide gas barrier, and antimicrobial activity were tested. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) were also performed to determine the degree of dispersion and exfoliation of nanoparticles. Mechanical test indicated that the reinforcement in the presence of the nanocomposites was more than that with their conventional counterparts, and the highest stiffness was achieved in a sample containing 5 wt % clay and 3 wt % TiO 2. Exfoliation of silicate layers and a good dispersion of TiO 2 nanoparticles in LDPE were achieved as confirmed by XRD and TEM. The gas barrier properties were improved after formation of the nanocomposites especially by insertion of 5 wt % of clay nanoparticles as a filler in the LDPE matrix. The photocatalytic effect of the nanocomposite film was carried out by antimicrobial evaluation against Pseudomonas spp. and Rhodotorula mucilaginosa and by ethylene removal test using 8 W ultraviolet (UV) lamps with a constant relative intensity of 1 mW cm 22. The greatest effects were recorded by combining UVA illumination and active film. It was also proven that the photocatalyst thin film with improved barrier properties prepared by extrusion could be used in horticultural product packaging applications.
Review of Recent Advances in Polylactic Acid/TiO2 Composites
Materials
Polylactic acid/titanium oxide (PLA/TiO2) composites as multifunctional materials have been studied extensively by couple of research groups owing to their outstanding mechanical, thermal, photocatalytic, and antimicrobial properties. This review describes the experimental approaches used to improve the compatibility of PLA/TiO2 composites. The mechanical, thermal, photocatalytic, and antimicrobial properties of PLA/TiO2 composites are discussed. The potential applications arising from the structural and functional properties of PLA/TiO2 composites were also reviewed. Finally, it is concluded that a deep understanding of the impacts of TiO2 filler with available improvement approaches in the dispersibility of this filler in the PLA matrix would be the key for the effective usage of PLA/TiO2 composites and to expand their suitability with worldwide application requirements.
Photochemical Characterization and Photocatalytic Properties of a Nanostructure CompositeTiO2Film
International Journal of Photoenergy, 2007
An efficient and new composite titania film photocatalyst was fabricated by sol-gel technique, using precalcined nanopowder titanium dioxide filler mixed with a sol, spin coating, and heat treatment. The structural and photocatalytic properties of these films were characterized using SEM, XRD, and UV/Vis spectroscopies. Problems of film inhomogenity and defects which caused peeling and cracking during calcination because of film shrinkage were overcome by using methylcellulose (MC) as a dispersant. Composite films heat-treated at approximately500∘C have the greatest hardness values. Surface morphology of composite deposits by scanning electron microscopy (SEM) showed that the composite films have much rougher surface than films made without MC. Photocatalytic activities of the composites film were evaluated through the degradation of three commercial diazo textile dyes, Light Yellow X6G (C.I. Reactive Yellow 2), Solophenyl red 3BL (C.I. Direct 80), and Tertrodirect light blue R (C.I...