UV-Shielding films of bacterial cellulose with glycerol and chitosan. Part 1: equilibrium moisture content and mechanical properties

Abstract

Bacterial cellulose films were combined with glycerol and chitosan to improve the UV-barrier and mechanical properties. In part 1, the moisture content and mechanical properties (tensile and puncture properties) were analysed by response surface methodology. The calculated values of the mechanical properties were in the range of 1.23-39.28 MPa for tensile strength, 2.28-25.34% for percentage of elongation, 11.72-1579.59 MPa for Young's modulus, 0.22-1.92 MJ/m 3 for toughness, 43.74-1067.35 g for burst strength and 0.39-3.12 mm for distance to burst. In general, a plasticizing and a reinforcing effect on the bacterial cellulose films was observed by glycerol and chitosan addition. Glycerol provided adhesive properties, which can be an advantage for application on foods, such as fruit or vegetables, as a wrapping material.Películas con protección UV de celulosa bacteriana, glicerol y quitosano. Parte 1: Contenido de humedad de equilibrio y propiedades mecánicas RESUMEN Se combinaron películas de celulosa bacteriana con glicerol y quitosano para mejorar las propiedades de barrera a la radiación UV y las propiedades mecánicas. En la parte 1, se analizaron el contenido de humedad y las propiedades mecánicas (propiedades de tracción y punción) mediante la metodología de superficie de respuesta. Los valores calculados de las propiedades mecánicas estuvieron en el rango de 1.23-39.28 MPa para resistencia a la tracción, 2.28-25.34% para porcentaje de alargamiento, 11.72-1579.59 MPa para módulo de Young, 0.22-1.92 MJ/m 3 para tenacidad, 43.74-1067.35 g para resistencia a la punción y 0.39-3.12 mm para la elasticidad de punción. En general, se observó un efecto plastificante y reforzante sobre las películas de celulosa bacteriana mediante la adición de glicerol y quitosano. El glicerol proporcionó propiedades adhesivas, que pueden ser una ventaja para su aplicación en alimentos, como frutas o verduras, como material de envoltura.

Bioactive Bacterial Nanocellulose Membranes Enriched with Eucalyptus globulus Labill. Leaves Aqueous Extract for Anti-Aging Skin Care Applications

“…This is evident by the significant increase in the value of the elongation at break from 3.6 ± 0.6% for BNC to 15.5 ± 1.4% for BNC-G, accompanied by a significant decrease in the Young’s modulus (from 10.1 ± 1.2 GPa for BNC to 0.5 ± 0.1 GPa for BNC-G) and in the tensile strength (from 237 ± 34 MPa for BNC to 40 ± 9 MPa for BNC-G). These results agree with previous studies regarding BNC-based materials incorporating glycerol as plasticizer [ 39 , 49 , 53 ]. As explained above, the incorporation of glycerol into the BNC network causes the reduction of the intermolecular forces between the cellulose nanofibrils, thereby increasing the inter-fiber space and their mobility, resulting in more elastic membranes [ 49 ].…”

Development and Characterization of Bio-Composite Films Made from Bacterial Cellulose Derived from Oil Palm Frond Juice Fermentation, Chitosan and Glycerol

“…Meanwhile, increasing the chitosan concentration in the formulation of BC/Ch films (without glycerol) from 0.5 to 1.0 %w/v slightly reduced the TS and YM of the bio-composite films. This is due to decreased intermolecular contact between the hydroxyl groups of BC and chitosan, resulting in a reduction in mechanical characteristics [33]. These findings differed slightly from those found in the literature.…”