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.

Three-dimensional (3D) bioprinting is a technique currently used for creating tissue engineering scaffolds, using bioinks as the building blocks. These bioinks are composed of biomaterials that provide structural integrity and are synthesized from organic polymers to enhance biocompatibility with the printed constructs. In this study, a series of eleven chitosan-based bioinks were synthesized using the sol-gel technique, employing chitosan of low and medium molecular weight. Three bioink formulations were selected based on their viscosity characteristics and further enriched with gelatin and hydroxyapatite (HA) to enhance their mechanical properties. Characterization tests included Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and rheological assessments. Viscoelastic materials were obtained, and an experimental model was developed to optimize printing parameters, focusing on pressure and printing speed. Our findings indicate that a bioink formulation comprising a blend of medium and high molecular weight chitosan, supplemented with gelatin and hydroxyapatite, was found to be a promising approach for fabricating scaffolds for bone tissue repair.

This is an editorial article. It has no abstract.

Herein, a novel approach was developed for the introduction of stabilizing compounds into polymers through a pre-impregnation process prior to processing, which is expected to improve their dispersion and, consequently, increase their efficacy. Ethylene-norbornene copolymer (EN) pellets were impregnated with quercetin or rutin in ethanol or a mixture of solvents (ethanol-dioxane (3:1)) for 24 h. Then, EN-based samples containing impregnated pellets were manufactured using a laboratory extruder. The research demonstrated that the materials containing impregnated pellets exhibited improved thermo-oxidation resistance, higher antibacterial effect (the number of dead cells increased from 8 to 59%), and satisfactory photostability. This may be a direct result of their better dispersion degree and their more gradual, controlled release from the EN during operation. If we compare the stabilizing effect of both polyphenols, quercetin was more efficient, which may be attributed to the presence of hydroxyl group at the C3 position in the C ring, which could increase the reactivity of the catechol structure of the B ring. The proposed approach effectively solves the issues that arise during the commonly used processing techniques and may facilitate the broader utilization of natural stabilizers in the polymer industry.