In this study, a new plastic film with antiviral and antibacterial properties was developed using modified cassava starch with glycidyltrimethylammonium chloride (GTMAC) and reinforced by crystalline nanocellulose (CNC), called Q-CS/CNC. For comparison, a control film (Q-CS) was produced without the addition of CNC. Elemental analysis revealed a degree of substitution (DS) of 0.552, indicating the replacement of the OH groups of starch by the NR₄⁺ groups of GTMAC during the quaternization reaction. The addition of CNC resulted in significant increases (p < 0.05) of 38.9, 38.2, and 43.1% in thickness, opacity, and water vapor permeability measurements, respectively, compared to Q-CS. Incorporating CNC also contributed to an increase of 43.6% in tensile strength and 109% in stiffness but slightly decreased thermal stability. The Q-CS/CNC film demonstrated efficacy by inactivating 99% of the coronavirus in 1 min and inhibiting the growth of Staphylococcus aureus and Escherichia coli. This action is attributed to the electrostatic interaction of quaternary amino groups, grafted onto starch, with the phospholipid membrane of microorganisms, resulting in the inactivation of these microorganisms. Therefore, these results highlight the potential use of Q-CS/CNC film as antimicrobial packaging, especially against coronavirus.

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.

This study demonstrated, for the first time, the successful formation of porous paramylon esters, which were made from euglenoid polysaccharide known as paramylon and short-chain fatty acids, through supercritical CO₂ processing. By maintaining a constant ester functional group attached to the paramylon and varying its proportion, distinct porous structures were selectively produced. Solubility parameter estimations indicated that changes in esterification had no significant effect on the solubility of the paramylon esters used in the experiment. Thus, these structural differences are likely attributed to variations in the viscoelastic properties of paramylon esters under supercritical CO₂ conditions. Furthermore, thermal conductivity measurements revealed reductions of up to 20%. Intriguingly, substantial decreases in thermal conductivity were observed even at low foaming ratios, achieved through precise control of the porous structure.

This review is focused on recent achievements in poly(lactic acid) (PLA) synthesis and copolymerization with special regard to biotechnological routes of PLA synthesis, which use bacteria/enzymes (e.g., enzymatic ring opening polymerization (eROP)). Besides PLA, also lactic acid (LA) synthesis is described and an emphasis is put on the biotechnological methods. Having regard to PLA copolymerization, this paper attempts to describe different types of PLA copolymers (such as block copolymers, PLA copolymers with polysaccharides, PLA-cellulose copolymer composites, and PLA polymer brushes). A detailed overview of the recent accomplishments in the field of PLA copolymers is presented. Various enhanced properties and applications of presented PLA copolymers are discussed. The attention is placed mainly on applications in the field of tissue engineering, drug delivery systems, and the packaging sector. Furthermore, a PLA market study and its economic forecast are presented. Eventually possible directions for future research in the field of PLA synthesis and copolymerization are indicated.

This research aimed to enhance the properties of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) biocomposites by incorporating hemp microcrystalline cellulose (MCC). Additionally, to improve interfacial adhesion between PHBV and MCC phases, a compatibilizer consisting of epoxidized natural rubber (ENR) grafted with microfibrillated cellulose (MFC) modified by vinyltrimethoxysilane (ENR-vinyl silanized MFC) was introduced. The addition of 5 wt% MCC increases the flexural modulus by approximately 65%. The use of ENR-vinyl silanized MFC as a compatibilizer demonstrated improved compatibility, as observed in scanning electron microscope (SEM) images. After 30 days of accelerated weathering (QUV) exposure, the flexural strength of the PHBV-based biocomposite with ENR-vinyl silanized MFC and MCC (vinyl silanized MFC biocomposite) was superior to that of the other samples. The remaining flexural strength can be sequentially categorized as follows: vinyl silanized MFC > MFC > non-MFC > PHBV. The Tg of PHBV-based biocomposites showed no significant change. Interestingly, the crystallinity of the vinyl silanized MFC biocomposite was the highest among all materials and demonstrated higher hydrophobicity. This makes the vinyl silanized MFC biocomposite a suitable material for construction, furniture, and both exterior and interior decoration.