Physicochemical and Antibacterial Properties of Alginate Films Containing Tansy (Tanacetum vulgare L.) Essential Oil

Tansy (Tanacetum vulgare) is a common plant used in folk medicine for digestive problems, fevers, and migraines; against parasites; and as an insect repellent. The active substances in essential oil are responsible for its antimicrobial and antioxidant activity. Thus, tansy essential oil (TO) was added to alginate films to fabricate materials with antioxidant and antibacterial properties for food packaging. Sodium alginate films with glycerol and TO were tested in terms of structure, mechanical, thermal, antioxidant, and antibacterial properties. The structure of the films was examined using SEM and an ATR-FTIR spectrophotometer. The addition of TO to the alginate film significantly changed the films’ microstructure, making them rougher and porous. A low-intensity band at 1739 cm−1, indicative of the presence of TO, appeared in all spectra of alginate films with TO. Moreover, the studies revealed that essential oil acted as a plasticizer, slightly reducing tensile strength from about 7 MPa to 5 MPa and increasing elongation at break from 52% to 56% for the sample with 2% TO. The alginate films enriched in TO exhibited antioxidant properties (280 μmol Trolox/100 g of the sample with 2% TO) and antibacterial activity against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa

Bionanocellulose/Poly(Vinyl Alcohol) Composites Produced by In-Situ Method and Ex-Situ/Impregnation or Sterilization Methods

The purpose of the work was to obtain composites based on bionanocellulose (BNC) and poly(vinyl alcohol) (PVA) for specific biomedical and cosmetic applications and to determine how the method and conditions of their preparation affect their utility properties. Three different ways of manufacturing these composites (in-situ method and ex-situ methods combined with sterilization or impregnation) were presented. The structure and morphology of BNC/PVA composites were studied by ATR-FTIR spectroscopy and scanning microscopy (SEM, AFM). Surface properties were tested by contact angle measurements. The degree of crystallinity of the BNC fibrils was determined by means of the XRD method. The mechanical properties of the BNC/PVA films were examined using tensile tests and via the determination of their bursting strength. The water uptake of the obtained materials was determined through the gravimetric method. The results showed that PVA added to the nutrient medium caused an increase in biosynthesis yield. Moreover, an increase in base weight was observed in composites of all types due to the presence of PVA. The ex-situ composites revealed excellent water absorption capacity. The in-situ composites appeared to be the most durable and elastic materials

Influence of Different Deep Eutectic Solvents and Plant Extracts on Antioxidant, Mechanical, and Color Properties of Alginate Film

International audienceEco-friendly functional alginate films with plant extracts (chokeberry pomace (ChP) or lemon balm (LB) herb) were obtained. Moreover, deep eutectic solvents (DESs) based on choline chloride, glucose, and betaine were used to acquire the active substances from plant materials. The films were tested regarding the antioxidant, mechanical, and color properties. The results revealed that the films' antioxidant capacities (AC) depended on the extract type and DES used, namely AC values for alginate films with LB were higher than those with ChP. Moreover, the results of the films' mechanical properties depended only on the DES, which acted as a plasticizer in most cases. Furthermore, the color analysis of the studied films showed a dependence on the type of extract and DES. The lightness (L*) was influenced only by the DES type, while the solvent and extract type affected the a* and b* values. Our results show that the films can be applied as active packaging for food products

Physicochemical and Antibacterial Properties of Alginate Films Containing Tansy (<i>Tanacetum vulgare</i> L.) Essential Oil

Tansy (Tanacetum vulgare) is a common plant used in folk medicine for digestive problems, fevers, and migraines; against parasites; and as an insect repellent. The active substances in essential oil are responsible for its antimicrobial and antioxidant activity. Thus, tansy essential oil (TO) was added to alginate films to fabricate materials with antioxidant and antibacterial properties for food packaging. Sodium alginate films with glycerol and TO were tested in terms of structure, mechanical, thermal, antioxidant, and antibacterial properties. The structure of the films was examined using SEM and an ATR-FTIR spectrophotometer. The addition of TO to the alginate film significantly changed the films’ microstructure, making them rougher and porous. A low-intensity band at 1739 cm−1, indicative of the presence of TO, appeared in all spectra of alginate films with TO. Moreover, the studies revealed that essential oil acted as a plasticizer, slightly reducing tensile strength from about 7 MPa to 5 MPa and increasing elongation at break from 52% to 56% for the sample with 2% TO. The alginate films enriched in TO exhibited antioxidant properties (280 μmol Trolox/100 g of the sample with 2% TO) and antibacterial activity against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa

Corona Charging of Isotactic-Polypropylene Composites

A new approach to obtaining piezoelectric polymeric films based on the isotactic-polypropylene (i-PP) using corona discharge with the energy of 45 W·min/m2 was presented. Detailed analyses with Atomic Force Microscopy (AFM) led to the conclusion that the surface quality was the important factor influencing the possibility of charging the i-PP composites, which was necessary to induce the permanent piezoelectric effect. It has been found that the high surface smoothness of the polymer films contributed to improved piezoelectric properties without the need for an additional polymer modification such as orientation, foaming or doping with fillers. The values of the piezoelectric constant, d33, of the studied samples were compared to these values for the analogous systems polarized with a constant electric field of 100 V/μm. The milder conditions of the film polarization during the corona discharge process are sufficient to achieve the electrets in i-PP films. The simple and cheap method proposed can be profitable in obtaining flexible electrets in the form of thin films for the production of personal biomedical sensors

Surface Studies of UV Irradiated Polypropylene Films Modified with Mineral Fillers Designed as Piezoelectric Materials

Isotactic-polypropylene (i-PP) films with inorganic minerals such as Sillikolloid, perlite, or glass beads were prepared. The obtained polymeric films were subjected to an orientation process. Moreover, this paper includes results how the artificial accelerated weathering influences surface properties of the unoriented and oriented i-PP films with the mineral fillers. Changes in the ultraviolet (UV) treated polymeric films were studied with attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and by measuring contact angles. The results revealed that photooxidation of i-PP was more effective in the presence of the fillers and depended on the type of the filler but not on its amount. Moreover, the oriented samples experienced more effective photooxidation compared with the unoriented ones. In all studied samples the same photoproducts were detected, suggesting the same route of polymer photooxidation with and without the filler. These polymeric films were produced for potential applications in the devices in which piezoelectric effect can be used