Biocomposites have recently received more attention because of raising environmental awareness and the drive toward sustainable technologies. The most common biodegradable polymer is poly(lactic acid) (PLA), which has an excellent balance of physical and rheological properties, but there is some limit to its usage. PLA properties can be improved by adding different types of fibers or fillers that come from agricultural waste. In this study, corn cob and lavender stem were used to reinforce PLA without any coupling agent, and the properties of the composites were investigated. The melt flow rate (MFR) values decreased with the corn cob content and increased with the addition of lavender stem. Mechanical tests showed that the tensile and flexural modulus of the composites increased and the strengths decreased with the reinforcement material content. The rigidness of PLA slightly decreased with the addition of fillers. There was no significant effect on the thermal properties. The unremarkable improvement of the reinforcement was due to the lack of appropriate adhesion of the two phases. The structure of the compounds was found to be homogenous on the scanning electron microscopy (SEM) micrographs. The incorporation of corn cob and lavender stem can reduce the production cost of materials.

The study investigates a ternary biopolymer blend composed of biopolymers polylactic acid (PLA), polyhydroxybutyrate- co-valerate (PHBV), and lignin extracted from patchouli fiber waste for sustainable packaging applications. A PLA: PHBV blend (70:30) was enhanced by incorporating hydrophobic lignin as a filler in varying loadings of 0, 3, 6, 9, and 12 wt%. The ternary blend was prepared using twin-screw extrusion process, pelletized, and compression-molded into specimens. Comprehensive characterization of the ternary blend included evaluations of water barrier, mechanical, functional, thermal, and morphological properties. Results demonstrated that lignin addition notably improved the compatibility between PLA and PHBV, leading to enhanced barrier performance, mechanical strength, and thermal stability. SEM morphology confirmed improved interfacial adhesion due to hydrophobic nature of lignin, which facilitated better dispersion at lower filler loadings. However, at 12 wt% lignin, property reductions were observed, attributed to lignin agglomeration and poor dispersion. Optimal performance was achieved at 9 wt% lignin loading, offering a balance of improved properties without compromising processability or structural integrity. This study highlights the potential of the PLA/PHBV/lignin ternary blend as a viable, eco-friendly material for sustainable packaging, showcasing improved functionality and environmental compatibility compared to conventional polymers.

Biopolymer-based packaging, such as bacterial cellulose (BC) and kappa-carrageenan (KC), offers a sustainable solution to environmental challenges. The incorporation of bioactive extracts enhances antioxidant and antimicrobial properties, while gamma radiation sterilization ensures microbiological safety, improving functionality for food preservation and promoting sustainability in the packaging industry. The objective of this work was to develop a BC film incorporated with KC solution (1%, v/v) and cashew bark extract (EC) at concentrations of 1, 2, and 4% (v/v) for use as active food packaging. EC exhibited a total phenolic content of 321.19 mgGAE/g and showed 86.67 and 99.54% radical scavenging activity for 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2″-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), respectively. EC also displayed antimicrobial activity against S. aureus and E. coli, confirming its antimicrobial potential. BC/KC films incorporated with EC and irradiated with gamma radiation exhibited a thermal degradation in the range of 275–287 °C, maintaining good thermal stability. The water vapor permeability decreased by 55.12%, indicating improved barrier properties and the film’s morphology became more compact after EC incorporation and irradiation. BC/KC films show promises for extending the food shelf life as active packaging.

Freeze-thaw (F-T) poly(vinyl alcohol) (PVA) as a soft network and ionic-crosslinked sodium carboxymethyl cellulose (CMC) as a hard network were applied to fabricate a double network (DN) gel using a one-step process. Mechanical properties of the DN gel using a high degree of hydrolysis PVA (PVA-CMC of 60-1) were significantly improved compared to that of a single network gel of PVA. The tensile strength of ~0.55 MPa and elongation at break of 179% could be achieved. The mechanical properties of PVA-poly(acrylic acid) DN gel were lower than that of PVA-CMC samples. Fourier-transformed infrared (FTIR) spectroscopy results showed less compatibility between polyacrylic acid (PAA) and PVA compared to that of CMC. The solution made from the lower hydrolysis degree PVA (PVA1788) could form a strong gel after being treated with NaOH 1 M. The FTIR result showed the disappearance of acetate groups. A large melting peak in differential scanning calorimetry (DSC) results showed high crystallinity of the hydrolyzed-PVA1788. The effect of various multivalent cations on the mechanical properties of PVA1788-CMC DN gel was performed. The properties of the samples followed the order: Fe³⁺<Co²⁺<Ni²⁺<Cu²⁺<Zn²⁺<Ca²⁺~Ba²⁺<Al³⁺. The tensile strength of DN gel fabricated using AlCl3 solution could reach 0.87 MPa, and the elongation at break was 330%.

This study investigated the development of thermoplastic composites by incorporating crude lignin extracted from coir fiber waste, into poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), a biodegradable polymer. The extracted crude lignin was blended with PHBV as a matrix, and spent coffee grounds (SCG) were used as biofillers. SCG were chemically modified through sodium hydroxide (NaOH) treatment and maleic anhydride (MA) grafting to enhance their compatibility with the PHBV/lignin blend. Raw and modified SCG were characterized for their functional, morphological, and thermal properties before being incorporated. Thermoplastic biocomposites were prepared via melt compounding and compression molding and evaluated for water barrier, morphological, mechanical, and thermal properties. Results showed that MA-grafted SCG significantly enhanced PHBV-lignin properties, increasing tensile strength by 23.7% and thermal stability by 11.9% compared to the control matrix. Optimal performance was observed at 5% MA-grafted SCG filler loading. However, higher SCG concentrations (7%) led to filler agglomeration, negatively affecting the material properties. This research demonstrated the potential of utilizing agricultural and food waste to create high-performance thermoplastic composites for future applications in biodegradable packaging, contributing to the advancement of a circular economy and environmental sustainability.