Oil-based Films Research Articles

Fabrication and Characterization of Chitosan and Gelatin-Based Antimicrobial Films Incorporated with Different Essential Oils.

This study was performed to check the effect of different essential oils on chitosan and gelatin-based antimicrobial films. Films prepared from biopolymers contain better mechanical strength but lack in moisture barrier properties. In order to increase the moisture barrier properties of chitosan and gelatin-based films in the current research work, different essential oils, i.e., thyme, cinnamon, basil, ginger, and cumin, at varying concentrations (1.0, 1.5, and 2.0%) were incorporated. Moreover, the concentrations of glycerol (plasticizer) and emulsifier (Tween 20) were kept constant to maintain homogeneity in the research. Antimicrobial films composed of gelatin and chitosan infused with essential oils were evaluated for their physicochemical (emulsion stability, particle size, and viscosity), FT-IR, microstructural (scanning electron microscopy), moisture barrier (water vapor permeability), and antimicrobial properties (E. coli, Salmonella, and S. aureus). Study outcomes elucidated significant variations (p < 0.05) as the concentration of essential oil was increased in the film solutions. An increased concentration of essential oil (2.0%) significantly enhanced the moisture barrier properties (1.12 ± 0.03 g.mm/kPa.h.m2). Nevertheless, the tensile strength decreased (38.60 ± 1.4 to 31.50 ± 1.5 MPa) from 1 to 2%. The increase in essential oil concentration in the emulsion-based films also influenced their physicochemical characteristics, such as droplet size, viscosity, and emulsion stability. At lower concentrations (1.0%), films exhibited a uniform microstructure but lacked moisture barrier properties. Antimicrobial properties against E. coli, Salmonella, and S. aureus showed an increased inhibition effect as the concentration of essential oil was increased. Of the essential oil-based films, ginger- and basil-based films showed greater inhibition effects as compared to the other essential oils. Overall, antimicrobial films containing a 1.5% concentration of ginger and basil oil showed better results as compared to the other treatments for mechanical, moisture barrier, and antimicrobial properties, while films with a 2.0% oil concentration showed better antimicrobial and moisture barrier properties but lacked in mechanical properties. Essential oil-based antimicrobial films have prospective applications in foods, specifically in fresh and processed food items such as seafood, meat, chicken, and sausages.

Assess the Possibility to Substituting Crude Oil-based Film Formers in Automotive Epoxy Metal Primers with Coconut oil-derived Bio-based Polyurethane Film Formers

There is a potential risk that diminishing some islands in the world map within a short time period due to global warming unless people divert into new strategies to use crude oil sustainability or replace with renewable resources. Polyurethane (PU) is one of the most popular film-forming materials in the coating industry because of its better performance. A coconut oil-derived biobased polyol (BBP) was synthesized and acid value, viscosity, reaction water release, oil length, FTIR spectrum, differential scanning calorimetry and Lovibond colourimetric index were assessed during the synthesis. A series of pigmented renewable polyurethane metal primer (RPUMP) wet samples were prepared by using BBP under two categories as direct-to-metal (DTM) primers and undercoat primers (UCP) in two mixing ratios with polyisocyanate hardener as 2:1 and 4:1. All samples were comparatively tested with crude oil born commercially available epoxy metal (CAEMP) primers in Sri Lankan market for apparent viscosity, fineness of grinding, solid content, specific gravity, gloss, drying time, hardness, dry film thickness, adhesion, impact resistance, water resistance, salt spray resistance and cylindrical mandrel bending. According to the results, it was proven that RPUMP showed overall better performances with the corresponded CAEMP under the DTM category. But under the UCP category RPUMP showed better performances in apparent viscosity, drying time and water resistance but equal magnitude for pencil hardness. CAEMP showed better performances in solid content, specific gravity, dry film thickness, flexibility, impact resistance and salt spray resistance.

Investigation of cottonseed oil as renewable source for the development of highly functional UV-curable materials

Containing unique combinations of triacylglycerols, plant oils derived from different sources, have a great potential to be used in various area of applications. Nowadays, among all of oils, soybean oil, which is also being used as food source, is the most explored in research for industrial uses. At the same time, other types of oils have been studied not nearly as much as soybean oil. This study explores the utilization of a cottonseed oil for the development of a bio-based UV-curable polymer resin. Since the fatty acid composition of cottonseed oil is very different compared to soybean oil, the products from this oil can be beneficial in entirely different applications. The combination of cottonseed oil as a raw material and the ultraviolet (UV) process as a curing technology presented in this work, provides an alternative “greener” solution for problems industry is facing. Acrylated-epoxidized cottonseed oil (AECO) was synthesized by the epoxidation of cottonseed oil via the peracetic acid method, followed by the acrylation of the epoxidized oil using acrylic acid. This polymer resin then was used as a main component in formulations and transformed into a crosslinked network by photopolymerization. In order to achieve the desired mechanical properties of the plant oil-based films, two reactive diluents, 1,6-hexandioldiacrylate and trimethylolpropane triacrylate, in different weight ratios were added separately to the formulations. The properties of the coatings, as well as their thermal and mechanical stability were evaluated. Moreover, comparing the AECO resin with an already existent commercially available product, the potential industrial use of AECO was assessed. In general, the results highlight increased flexibility of AECO-based materials compared to petroleum-derived ones, which is beneficial for many applications, including, but not limited to wood substrates, printed electronics, paper products. The study concluded that functionalized resins obtained from cottonseed oil can provide a competitive and sustainable alternative to accommodate the rapid growth in the use of bio-based UV-curable materials.

Hydrophobic Starch-Based Films Using Potato Washing Slurries and Spent Frying Oil.

Starch is a promising candidate for preparing biodegradable films with useful gas barriers and thermoplastic capabilities. However, these materials are hydrophilic and brittle, thus limiting their application range. To overcome these drawbacks, it has been hypothesized that starch can be hydrophobized and plasticized during the starch-based film production using a single-step approach and following transesterification principles. In this work, KOH powder and spent frying oil (SFO) were used as an alkaline catalyst and a source for triacylglycerides, respectively, to promote the modification of starch. Different ratios of SFO (w/w related to the dried starch weight) were tested. When compared to the neat films (without a catalyst and SFO), the incorporation of at least 15% SFO/KOH gave rise to transparent, hydrophobic (water contact angles of ca. 90°), stretchable (ca. 20×), elastic (ca. 5×), and water tolerant starch-based films, contrary to the films produced without the catalyst. ATR-FTIR and 1H NMR revealed structural differences among the produced films, suggesting that starch was modified with the SFO-derived fatty acids. Therefore, adding KOH during the potato starch/spent frying oil-based film’s production was determined to be a promising in situ strategy to develop starch-based materials with improved hydrophobicity and flexibility, while valorizing the potato chip industry’s byproducts.

Durability of Selected Transparent and Semi-Transparent Coatings on Siberian and European Larch during Artificial Weathering

This paper compares the resistance of 20 commercial transparent and semi-transparent coatings applied to European and Siberian larch during artificial weathering in Xenotest. The change in gloss, colour, contact angle of wetting, resistance to Aspergillus niger and Penicillium brevicompactum moulds was evaluated, and visual changes at the top surface of treated wood species were measured. Overall, the durability of coatings on European larch was higher than that on Siberian larch. The most durable of the tested coatings was a thin-film, i.e., semi-transparent oil-based film containing TiO2 pigment and propiconazole fungicide. Of the transparent coatings, the most stable was a thick acrylic coating. Conversely, penetrating transparent oil systems had low colour stability and overall lifespan. Artificial weathering of all of the coatings resulted in a marked decrease in their resistance to moulds.

Investigation of Antibacterial 1,8-Cineole-Derived Thin Films Formed via Plasma-Enhanced Chemical Vapor Deposition.

The need for low-fouling coatings for biomedical devices has prompted considerable interest in antibacterial compounds from natural and sustainable sources, such as essential oils. Herein, a tea tree oil-based precursor, 1,8-cineole, is used to fabricate antimicrobial films (denoted ppCin) by plasma-enhanced chemical vapor deposition. Film properties were comprehensively characterized using a variety of surface and bulk analytical tools, and the plasma gas phase is assessed using optical emission spectroscopy, which can be correlated to ppCin film properties. Notably, film wettability increases linearly with plasma pressure, yielding water contact angles ranging from ∼50° to ∼90°. X-ray photoelectron spectroscopy reveals less oxygen is incorporated at higher pressures, likely arising from the lower density of OH(g) species. Further, we utilized H2O(v) plasma surface modification of the ppCin films to improve wettability and find this results in a substantial increase in surface oxygen content. To elucidate the role of film wettability and antibacterial properties, both as-deposited and H2O(v) plasma-modified films were exposed to Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus using glass slides and hydrocarbon films deposited from 1,7-octadiene as positive controls. Overall, bacteria attach to a similar extent on all films, including controls, yet only essential oil-based films significantly prevent biofilm formation (4-7% coverage compared to ∼40% for controls).

Antimicrobial efficacies of essential oils/nanoparticles incorporated polylactide films against L. monocytogenes and S. typhimurium on contaminated cheese

ABSTRACTPolylactide based films were formulated by incorporating polyethylene glycol, selected nanopowders (zinc oxide, silver-copper), and essential oils (cinnamon, garlic, and clove) by solvent casting method. Films were tested against three foodborne pathogens (one gram-positive and two gram-negative) for their antibacterial activity. The effectiveness of selected cinnamon oil-based film was ascertained by performing a challenge test with cheese as a food model. In vitro antibacterial efficacies of nanopowders and essential oils were also determined by the decimal reduction concentrations and the minimum bactericidal concentrations for those foodborne pathogens. It was observed that nanopowders exhibited considerably poorer decimal reduction concentrations and minimum bactericidal concentration values in comparison to the essential oils. Silver-copper alloy nanopowders exhibited lower decimal reduction concentrations and minimum bactericidal concentrations values than ZnO against tested pathogens whereas essential oils showed distinct antimicrobial effectiveness against all those pathogens with in vitro decimal reduction concentration values of 87–157 and 77–220 µg/mL for cinnamon and clove oils, respectively. Among the various formulations, it was observed that only essential oils (especially cinnamon and clove) incorporated films exhibited a significant antimicrobial activity against the selected microorganisms. These results indicate that the poor antibacterial activity of the nanopowders and the hydrophobicity of polylactide could be responsible for the ineffectiveness of nanopowders in polylactide based films. Furthermore, the challenge test indicated the polylactide/polyethylene glycol/cinnamon oil film was appropriate to inhibit the growth of L. monocytogenes and S. typhimurium on cheese up to 11 days at refrigerated storage.

Antimicrobial, Rheological, and Thermal Properties of Plasticized Polylactide Films Incorporated with Essential Oils to Inhibit Staphylococcus aureus and Campylobacter jejuni.

Polylactide (PLA) is the most mature biobased and biodegradable polymer. Due to its inherent brittleness, the polymer cannot be used as a packaging material without plasticizer. An attempt was made to develop antimicrobial plasticized PLA film by incorporating polyethylene glycol (PEG) and 3 essential oils (EO), namely cinnamon, garlic, and clove by solvent casting method. Physical, thermal, and rheological properties of those films were evaluated for practical applications whereas the antimicrobial properties were tested against Staphylococcus aureus and Campylobacter jejuni-pathogens related to poultry industry. Both PEG and EOs led to the formation of flexible PLA/PEG/EO films with significant drop in the glass transition temperature (Tg ), and mechanical property. Time-temperature superposition (TTS) principle was employed to melt rheology of EO-based films at selected temperature, and rheological moduli superimposed well in an extended frequency range. Among EOs, cinnamon and clove oil-based films (PLA/PEG/CIN and PLA/PEG/CLO) exhibited a complete zone of inhibition against C. jejuni at the maximum concentration (1.6 mL per 2 g PLA/PEG blend) whereas the garlic oil-based film (PLA/PEG/GAR) had the lowest activity.

Effects of oil type on the properties of short oil alkyd coating materials

Short-oil alkyd resins were prepared by using five different oil types: corn oil, rice bran oil, sunflower oil, soya bean oil and dehydrated castor oil (DCO). Among these, soya bean oil gave alkyd resin with the darkest color because oxidation occurred. Auto air-dried coating films were developed and it was shown that film prepared from rice bran oil-based alkyd exhibited the longest drying time due to the low number of double bonds compared to other and the extra natural antioxidant in rice bran oil. DCO alkyd-based film revealed the shortest drying time, the greatest hardness but the poorest alkali and sea-water resistance. This is caused by the differences in the type of fatty acid and double bonds, the high amount of double bonds being in DCO. In addition, an increase in the reaction temperature only had an influence on darkening the alkyd color and decreasing the drying time of coating films. In terms of technical properties and cost competitiveness, soya bean oil-based film is the best. Coating films derived from all oil-based alkyds, except DCO, look promising for use in surfboard manufacturing.

Influence of emulsifier type and content on functional properties of polysaccharide lipid-based edible films.

This study investigates the effect of different types of surfactant (glycerol monostearate, Tween 60, and Tween 80) on water vapor permeability (WVP), tensile strength (TS), percentage elongation at breaking (E), and structure of an emulsified edible film composed of cornstarch, methylcellulose, and cocoa butter or soybean oil. Factorial designs at two levels were used to analyze the effect of emulsifier (EM) and lipid content on the functional properties of film. Results showed that the effects of independent variables on WVP, TS, and E depend on surfactant and lipid type. The presence of EM significantly decreased the WVP of cocoa butter films but did not improve the barrier or mechanical properties of soybean oil-based film.