Synthesis of clay-TiO 2 nanocomposite thin films with barrier and photocatalytic properties for food packaging application (original) (raw)
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LWT - Food Science and Technology, 2013
The ability to inactivate Pseudomonas spp. and Rhodotorula mucilaginosa by a photocatalyst thin film, obtained via a combination of anatase and rutile titanium dioxide incorporation into a low density polyethylene (LDPE) polymeric matrix by a melt blending method, was addressed in this study. The number of surviving cell of the Pseudomonas spp. was decreased by 4 log CFU/ml and 1.35 log CFU/ml after 3 h of UVA illumination on TiO 2 nanocomposite thin film and LDPE thin film, respectively. The number of cells of R. mucilaginosa decreased by 2 log CFU/ml and 0.64 log CFU/ml on TiO 2 nanocomposite thin film and LDPE thin film, respectively. In an in vivo test carried out on fresh pears packaged in TiO 2 nanocomposite film and stored under illumination by a fluorescent light lamp at 5 C for 17 days, the number of mesophilic bacteria and yeast cells decreased significantly compared to samples stored in LDPE film. The greatest effects were recorded by combining UVA illumination and active film. It was also proven that the photocatalyst thin film prepared by extrusion could be effectively used in fruit packaging applications.
Applied Surface Science, 2012
Nanostructured, photoactive anatase TiO 2 sol prepared under very mild conditions using titanium tetraisopropoxide as the precursor is used to functionalise extruded expanded polystyrene (XPS) sheets by spray-coating resulting in stable and active materials functionalised by TiO 2 nanoparticles. Photocatalytic tests of these sheets performed in a batch reactor in gas-solid system under UV irradiation show their successful activity in degrading probe molecules (2-propanol, trimethylamine and ethene). Raman spectra ensure the deposition of TiO 2 as crystalline anatase phase on the polymer surface. The presence of TiO 2 with respect to polymer surface can be observed in SEM images coupled to EDAX mapping allowing to monitor the surface morphology and the distribution of TiO 2 particles. Finally thermoforming of these sheets in industrial standard equipment leads to useful containers for foodstuffs.
Polymer Composites, 2011
Poly(lactic acid)/titanium dioxide (TiO 2 ) composite films were prepared by direct melt processing using three different procedures (i.e., compression molding, twin-screw melt extrusion, and melt extrusion and thermoforming). The effect of TiO 2 loading and processing procedures on the phase morphology and on the thermal, mechanical, and barrier properties of the obtained nanocomposites were analyzed respectively by field-emission scanning electron microscopy-energy dispersive spectrometry, differential scanning calorimetry, universal testing machine, and water vapor and oxygen permeability measurements. The incorporation of TiO 2 nanoparticles into the poly(lactic acid) matrix increased the crystallinity and improved the barrier properties of the composites. The maximum tensile strength was achieved at the 2% content of TiO 2 for the films produced by compression molding and twin-screw melt extrusion, whereas the tensile strength for films produced by melt extrusion and thermoforming decreases markedly with an increasing TiO 2 content. The photocatalytic activities of the obtained nanocomposites were investigated by analyzing the degradation of methyl orange. Results confirmed that the processing procedures and the distribution of TiO 2 in the polymer matrix are the key parameters, which rule the photocatalytic behavior of composite films. POLYM. COMPOS., 32:519-528,
Reactive and Functional Polymers, 2020
Zwitterion polyurethanes (ZPU) are used for non-fouling and antimicrobial surfaces but their sensitive nature under ultraviolet (UV) radiations limits the requirements of engineering materials. Herein, ZPU is successfully synthesized and then prepared different TiO 2 /ZPU composites, aiming to increase the service life of ZPU and to form active film for food packaging applications. The thermo-mechanical results revealed that the 4% TiO 2 /ZPU sample exhibits better performance, as evidenced through tensile testing and surface morphology analysis. The UV-Vis spectra results indicated that the rutile TiO 2 nanoparticles can enhance the UV absorption and visible light reflectance, decreasing photoaging properties of composites thereby prolonging its shelf life. Moreover, scanning electron microscopy (SEM) observation after 5 h irradiation of UV light confirmed the photostability of TiO 2 /ZPU composite film. Further, the antioxidant ability of ZPU is increased from 51% to 71% with TiO 2. The results of antimicrobial activity of TiO 2 /ZPU demonstrate strong bacterial growth inhibition against E. coli that regards its suitability for food and other packaging applications. Besides, the food preservation ability is monitored by visual changes of tomato fruit. In essence, we anticipate that the TiO 2 /ZPU composite films possessed all expected features to be considered as photostable material for food packaging.
Food Chemistry, 2013
A high density polyethylene (HDPE)/calcium carbonate (CaCO 3 ) film containing TiO 2 was prepared via blown film extrusion process. The photocatalytic properties of this film were evaluated by voltammetric, UV-Vis spectrophotometric and gas chromatographic measurements following the decomposition rate of suitably selected molecular probes, such as 4-hydroxybenzoic acid and methylene blue. The film containing 1% w/w of TiO 2 displayed a profitable and reproducible photoinduced degradation activity towards target organic compounds. The effect of packaging photocatalytic activity on the structural and microbiological stability of a short-ripened cheese was studied. Cheese structure was assessed by dynamic, small deformation rheological tests. A container consisting of a multilayer material, where the layer brought in contact with the food, made from the HDPE + CaCO 3 + TiO 2 composite matrix, was able to provide a greater maintenance of the original cheese structure than a rigid container currently used, mainly due to the inhibition of lactic acid bacteria and coliforms.
Preparation and characterisation of photocatalytic TiO2 thin films
2005
Architectural mortar is used in the building sector when aesthetic surface value is required and therefore, these surfaces present a great potential to be used as a solution for the reduction of atmospheric pollution. In the present work, an inorganic ultramarine blue pigment has been modified to provide the mortars with colour and photocatalytic properties, simultaneously. To modify the pigment, a sol-gel coating based on titanium n-butoxide precursor has been applied on its surface. The influence of different parameters affecting the coating formation, such as the pH and titanium weight content of the sol-gel reactants, has been studied. Moreover, the formation of a coating on the pigment's surface with several amounts of TiO 2 anatase nanoparticles has also been explored. A pigment with better photocatalytic properties has been obtained at pH = 12 applying a coating based on titanium n-butoxide precursors (Ti precursor/pigment weight ratio = 0.5) with 2 wt.% of titania anatase nanoparticles, maintaining the original pigment colour. Moreover, mortars with the new pigment present higher flexural strength and similar compressive strengths than non-modified mortars ensuring the applicability of the pigment in the building sector.
Synthesis of LDPE/Nano TiO2 Nanocomposite for Packaging Applications
International Journal of NanoScience and Nanotechnology, 2012
Improving barrier properties through the use of nanocomposites is an important area of research, especially for the food packaging industry. In this work, Titanium dioxide (TiO2 )/Low density Poly Ethylene (LDPE) nanocomposites were synthesized as the oxygen barrier layers through the co-extrusion process. The Oxygen permeability of the nanocomposite with 4% of TiO2 decreased for about 16% compared to the pristine LDPE. Furthermore, the rancidity of almonds in the packaging which is made of the former is about 78% less than the latter. Therefore, from the data obtained from the permeation, mechanical and degradation experiments, it can be concluded that these nanocomposites provide promising applications as O2-barrier and antidegradation agents in food packaging.
Polymeric hybrid films with photocatalytic activity under visible light
Journal of Applied Polymer Science, 2018
The immobilization of photocatalysts on several kinds of substrates has been widely studied over the past few years, focusing mainly on improving its industrial application. In this work, novel hybrid films were prepared, employing TiO 2 P25, commercial ZnO or BiOI, synthetized through hydrothermal method and immobilized on poly(vinylidene fluoride) by the non-solvent-induced phase inversion technique. Subsequently, the prepared composites were evaluated by photodegradation of methylene blue (MB) under ultraviolet or visible light. The samples were also characterized by scanning electron microscope, thermo-gravimetric analysis, attenuated total reflection-Fourier transform infrared spectroscopy, and X-ray diffractometer analysis to improve comprehension of the composites' photocatalytic behavior. The degradation reaction of the contaminants exhibited pseudo-first order kinetics in all samples, and achieved better performance when compared to simple photolysis. The recyclability of the hybrid films was also evaluated and proved that polymeric matrix is a promising material for the preparation of composites for photocatalysis applications. V C 2018
Morphological and thermal properties of photodegradable biocomposite films
Journal of Applied Polymer Science, 2012
Biocomposites containing UV absorbing inorganic nanofillers are of great interest in food packaging applications. The biodegradable polylactide (PLA) composite films were prepared by solvent casting method by incorporating 1 wt % of TiO 2 and Ag-TiO 2 nanoparticles to impart the photodegradable properties. The films were exposed to UV irradiation for different time periods and morphology of the composite films before and after UV exposure were investigated. The results showed that homogenous filler distribution was achieved in the case of Ag-TiO 2 nanoparticles. The thermal properties and thermo-mechanical stability of the composite film containing Ag-TiO 2 were found to be much higher than those of neat PLA and PLA/TiO 2 composite films. The scanning electron microscopy and X-ray diffraction studies revealed that the photodegradability of PLA matrix was significantly improved in the presence of Ag-TiO 2 nanoparticles.