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In the present study, supercritical solvent impregnation (SSI) has been applied to incorporate thymol into bio-composite polymers as a potential active packaging material. Thymol, a natural component with a proven antimicrobial activity, was successfully impregnated into starch-chitosan (SC) and starch-chitosan-zeolite (SCZ) films using supercritical carbon dioxide (scCO2) as a solvent. Experiments were performed at 35 &deg, C, pressures of 15.5 and 30 MPa, and an impregnation time in the range of 4&ndash, 24 h. The highest impregnation yields of SC films with starch to chitosan mass ratios of 1:1 and 1:2 were 10.80% and 6.48%, respectively. The addition of natural zeolite (15&ndash, 60%) significantly increased the loading capacity of films enabling thymol incorporation in a quantity of 16.7&ndash, 27.3%. FTIR and SEM analyses were applied for the characterization of the films. Mechanical properties and water vapor permeability of films before and after the impregnation were tested as well. Thymol release kinetics in deionized water was followed and modeled by the Korsmeyer-Peppas and Weibull model. SCZ films with thymol loading of approximately 24% exhibited strong antibacterial activity against E. coli and methicillin-resistant Staphylococcus (S.) aureus (MRSA).

Copper-based alloys and composites, owing to their convenient properties, are being considered essential materials in various industries. Since copper possesses an ability to develop high corrosion resistance, putting it in the domain of a desirable material in the manufacturing of valves, pipes, and also systems that carry industrial gases and aqueous fluids. Its usage is also invaluable for cables and electrical wires. This review paper describes diversity in copper alloy processing techniques (powder and ingot metallurgy) which are alongside the phase transformation kinetics interpreted and explained in detail. Furthermore, the focus is put on the copper alloys, as well as the kinetics present in these systems, with the application being highlighted. Correlation between physical properties and phase transformation kinetics in copper alloys is made. It is shown that if certain alloying elements are to be added, different properties could be improved. The effect of phase precipitation on phase transformation kinetics of copper alloys is shown by studying the Cu–15Ni–8Sn alloy.

The antibacterial ability of in situ prepared nanometer-sized silver particles, immobilized in agar-agar films, was studied as a function of the concentration of co-dopant, magnesium ions. Content of inorganic components in hybrid films was determined using inductively coupled plasma optic emission spectroscopy, and found to be low (

New agar-based composite films with increasing Cu-carbonate and Cu-phosphate mineral phase content were prepared by in situ mineralization and solvent casting method. SEM and optical analysis revealed that Cu-carbonate phase had better compatibility with agar matrix than Cu-phosphate phase. Incorporation of both mineral phases improved mechanical and water vapor barrier properties of the obtained mineralized films, in concentration dependent manner. When 5 mM of carbonate precursor was incorporated into agar matrix, mechanical resistance was enchanced for 44% and water vapor barrier property for 40%. The release of Cu (II) was higher in acidic conditions for both mineralized composites and remained in the range of specific release limits for this metal. In addition, both mineralized composite films exhibited distinctive antimicrobial activity against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria. Overall, the Cu-carbonate and Cu-phosphate mineralized agar films showed potential to be used for food packaging materials, agriculture or medical purposes. © 2019 Elsevier Ltd

Environmental-friendly pectin-TiO2 nanocomposite aerogels were prepared via sol-gel process and subsequent drying under supercritical conditions. The first step includes dissolution of pectin in water, addition of proper amount of TiO2 colloid and crosslinking reaction induced in the presence of tert-butanol and zinc ions. Then, the gels are subjected to the solvent exchange and supercritical CO2 drying. The influence of TiO2 nanoparticles on the textural, mechanical, thermal and antibacterial properties of aerogels was investigated. Results indicate that in the presence of TiO2 nanoparticles (NPs) mechanical, thermal and antimicrobial properties of pectin-based aerogels are improved in comparison to the control pectin aerogels. It should be emphasized that the thermal conductivity of pectin-based aerogels (0.022–0.025 W m−1 K−1) is lower than the thermal conductivity of air. Generally, the results propose that the pectin-TiO2 nanocomposite aerogels, as bio-based material, might have potential application for the storage of temperature-sensitive food.

The aim of this study was to develop dextran-based edible films plasticized by sorbitol. In order to optimise the film-forming formulation, response surface methodology was used. The influence of dextran and sorbitol concentration on the mechanical and water vapour barrier properties of obtained films was investigated. The results showed that both parameters exhibited significant effect on the water vapour permeability of a film. Both dextran and sorbitol concentration had significant influence on tensile strength and elongation at break, whereas only sorbitol concentration had significant effect on Young’s modulus. After optimisation by desirability approach, it was found that a film made of 3.40 wt% of dextran and 20.43 wt% of sorbitol showed the lowest water vapour permeability and the highest tensile strength and elasticity.

Manufacturing of synthetic composites consumes huge energy and their disposal at the end of the life cycle is very difficult since there is virtually no recycling option. Therefore, biocomposite materials have recently received considerable attention in academic research and industrial application compared to the synthetic composite materials due biodegradability, nontoxicity and economical point of view. Biocomposite membranes of highly methylated pectin and SBA-15, a form of mesoporous silica, were prepared by membrane casting. The amount of SBA-15 was 10%, 20% and 30% by membrane mass. These membranes were characterized by optical microscopy, FTIR, XRD, thermogravimetry, mechanical analysis and swelling in water, HCl, NaOH and methanol. The incorporation of SBA-15 in pectin matrix enhanced the stability of these membranes in all tested solutions, compared to the pure pectin membranes. The pectin/SBA photomicrographs contain rod-like domains which indicate the presence of SBA-15 in membrane. Mechanical analysis proves that incorporation of SBA-15 enhances the elasticity and tensile strength of pectin membranes. Thermogravimety in nitrogen has shown that the presence of SBA-15 in the membranes increased the onset temperatures of pectin degradation. The novel composite material represents promising way for practical membrane application. (C) 2014 Elsevier Ltd. All rights reserved.

In this work, antimicrobial bioinspired films made from chitosan incorporated with triclosan were investigated. The tensile strenght of these films were in the range of 33 and 39 MPa, which presented satisfied mechanical stability comparable to the synthetic-based packages commonly used in industry. The addition of triclosan enhanced thermal stability and antimicrobial activity of chitosan films against Escherichia coli and Staphylococus aureus . Results obtained in this work demonstrated that chitosan/triclosan films could be potentially used as an eco-sustainable package in healthcare sector to prevent infections/contaminations.

In this work, the new biodegradable blend films composed of natural polymer pectin and synthetic polymer polyvinylpyrrolidone were obtained through casting process. The concentration of glycerol in all formulations was constant (2% v/v), while the amount of polyvinylpyrrolidone varied from 20 to 60% by mass of pectin. The molecular interactions between two components were elucidated by FTIR-ATR spectroscopy, while functional properties of these films were carried out by determination of puncture resistance, tensile strength, thermal stability, water vapor barrier, wettability and printability. The blending of pectin with PVP led to an improvement of mechanical resistance, barrier properties and hydrophobicity of these films for 57%, 58 and 24%, respectively, remaining adequate thermal stability. Since pectin and PVP are nontoxic, food-grade and biodegradable materials, this research present an ecosustainable approach to provide films with satisfied physical properties for use as packaging material of non-food products, such as water-treatment products (detergents, biocides, agrochemical compounds). (C) 2016 Elsevier Ltd. All rights reserved.

Biomorphous β-SiC ceramics were produced from linden wood by impregnation with tetraethyl orthosilicate (TEOS), followed pyrolysis and high temperature treatment at 1580°C. Six specimen groups included charcoal and five groups with different number of impregnation were analyzed. Flexural and compressional strength of charcoal and woodlike SiC ceramic were characterized using three-point and compression testing. Mechanicall properties increased slightly with number of impregnation cycles. Ultrasonic pulse velocity testing (UPVT) was used to determine dynamic young modulus of elasticity. Laser surface modification was studied by interaction with Nd:YAG laser, operating at 1064 or 532 nm wavelengthss and pulse duration of 150 ps. Biomorfna keramika β-SiC je dobijena od karbonizovane lipe uz impregnaciju tetraetil ortosilikatom (TEOS), sa karbotermalnom redukcijom na 1580°C. Ispitivano je šest grupa uzoraka - karbonizovano drvo i pet grupa biomorfnog SiC sa različitim brojem impregnacija. Čvrstoće na savijanje i kompresiju karbonizovanog drveta i biomorfnog SiC je merena primenom metoda savijanja u tri tačke i testiranja kompresije. Mehanička svojstva su se postepeno poboljšavala sa brojem ciklusa impregnacije. Određivanje dinamičkog modula elastičnosti je vršeno pomoću merenja brzine ultrazvučnih impulsa (UPVT). Za proučavanje površinske interakcije sa laserskim zračenjem korišćen je Nd:YAG laser koji je emitovao zračenje na talasnim dužinama 1064 i 532 nm i trajanjem impulsa 150 ps.

Biomorphous beta-SiC ceramics were produced from several species of wood such as ash, wild cherry, black alder, Persian walnut, sessile oak and European hornbeam. The wood was pyrolysed, impregnated with tetraethyl orthosilicate (TEOS) sol in repeated cycles and thermally treated at 1800 degrees C in vacuum. Four specimen groups included charcoal and three groups with 1, 3 and 5 cycles of impregnation were analyzed. Flexural and compressional strength of charcoal and woodlike SiC ceramics were measured using three-point and compression testing in different directions. Experimental results showed that mechanical properties of woodceramics were improved by repeating of impregnation cycles. Porosity measurement, dilatometric analysis, XRD and SEM analysis were used to study the macroscopical and microscopical properties of the resulting biomorphic SiC ceramics. (C) 2013 Elsevier Ltd and Techna Group S.r.l. All rights reserved.