Melt processability, characterization, and antibacterial activity of compression-molded green composite sheets made of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) reinforced with coconut fibers impregnated with oregano essential oil

Abstract

New packaging materials based on green composite sheets consisting of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and coconut fibers (CFs) were obtained by twin-screw extrusion (TSE) followed by compression molding. The effect of varying the CF weight content, i.e. 1, 3, 5, and 10 wt.-%, and the screw speed during melt processing, i.e. 75, 150, and 225 rpm, on both the aspect ratio and dispersion of the fibers was analyzed and related to the properties of the compression-molded sheets. Finally, the CFs were impregnated with oregano essential oil (OEO) by an innovative spray coating methodology and then incorporated into PHBV at the optimal processing conditions. The functionalized green composite sheets presented bacteriostatic effect against Staphylococcus aureus from fiber contents as low as 3 wt.-%. Therefore, the here-prepared CFs can be successfully applied as natural vehicles to entrap extracts and develop green composites of high interest in active food packaging to provide protection and shelf life extension.

Valorization of Linen Processing By-Products for the Development of Injection-Molded Green Composite Pieces of Polylactide with Improved Performance

“…The use of lignocellulosic fillers in biopolymers offers significant processing advantages, biodegradability, non-abrasive, low cost, high specific strength, and a renewable nature [8]. Over the last few years, several articles and applications of green composites have been developed using lignocellulosic fillers derived from food, agricultural, industrial, and marine wastes such as rice husk [9,10], almond shell [11], walnut shell [12], peanut shell [13], coconut fibers [14], orange peel [15], recycled cotton [16], and posidonia oceanica seaweed [17]. In this regard, flax (Linum usitatissimum L.) is one of the most researched plants for industrial purposes.…”

Electrospun Active Biopapers of Food Waste Derived Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) with Short-Term and Long-Term Antimicrobial Performance

“…In particular, the antimicrobial activity of OEO has been related to its high content in carvacrol and thymol [15]. Further details about the antimicrobial properties of OEO can be found in our previous research works [5,57]. Alternatively, it can be observed that ZnONPs presented the same values of MIC and MBC for both E. coli and S. aureus bacteria.…”

“…Nanomaterials 2020, 10, 506 2 of 26 studied, including the poly(3-hydroxybutyrate) (PHB or P3HB) homopolyester and its copolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). The latter shows lower crystallinity and melting point as well as greater flexibility, which broadens its industrial applicability [4,5]. In order to confer active properties to PHAs, several substances can be incorporated into the biopolymers such as essential oils (EOs) and inorganic or metal nanoparticles (MNPs) [6,7].EOs are the product of the secondary metabolism of plants, separated from the aqueous phase, which is formed by various volatile components such as terpenes, alcohols, acids, esters, epoxies, aldehydes, ketones, amines, and sulphides, among others [8].…”

Biofunctionalization of Natural Fiber-Reinforced Biocomposites for Biomedical Applications

“…In this context, biocomposites of cotton modified with monochlorotriazinyl β-cyclodextrin, as an eco-friendly encapsulating/hosting compound, have been proposed for the formation of core-shaped hydrophobic cavities for individual loading of EOs [113]. The fibers contained in the peals of fruits like durian and coconuts have also been combined with synthetic polymers for the encapsulation of cinnamon [15] and oregano oils [116], respectively. Aside from enhancing the physical properties of the biocomposite, these EOs demonstrated improved antimicrobial action against Gram-positive and Gram-negative bacteria; this way attesting to the exceptional performance of EO-modified biocomposites.…”