Research efforts are increasingly directed towards the development of biodegradable polymers derived from renewable agricultural resources. Polymer blends, which combine multiple polymers, offer enhanced properties such as ductility and toughness while being more cost-effective compared to the development of specialized copolymers. This study examines nine binary and four ternary blends of polylactic acid (PLA), poly(butylene succinate-co-adipate) (PBSA), and polyhydroxyalkanoate (PHA). The morphology of most blends was characterized by spherical inclusions. Binary blends with a 50/50 wt% ratio demonstrated distinctly different interactions between the bioplastics. The addition of PBSA increased both tensile elongation and impact strength. Notably, the PLA/PBSA blend with a 30/70 wt% ratio exhibited an elongation at break of 172%. In blends where PBSA constituted 30 wt%, there was an increase in impact strength, from 15% to 29% in PHA/PLA and PLA/PBSA blends, respectively. Overall, PBSA exhibited better compatibility with PLA compared to PHA. Mechanical testing of ternary blends was integrated with the binary blends' results to construct ternary diagrams. Dynamic mechanical analysis revealed that the glass transition temperatures in PBSA binary blends remained largely independent of the blend composition. Calorimetric analysis revealed a shift in crystallization behavior. This research highlights the potential of biopolyester blends in developing bioplastics with tailored mechanical properties for applications in automotive, agriculture, food packaging, and shape memory materials.

The environmental degradation of biodegradable polyester parts prepared via fused filament fabrication (FFF) from poly(butylene succinate) (PBS)/poly(lactic acid) (PLA) and PBS/poly(hydroxybutyrate) (PHB) blends (5/5 and 7/3 w/w) was systematically studied in static artificial seawater over six months. In contrast to typical thin-film degradation studies, bulk specimens provide realistic insights into the degradation behavior of thicker polymer products encountered in practical marine applications. 3D-printed dumbbell specimens fabricated with concentric and rectilinear infill patterns were investigated to tackle this issue and respond to emerging additive manufacturing trends. Changes in mechanical performance were significant, with the PBS/PHB (5/5) blend showing a pronounced 3.3-fold reduction in ultimate strength and a 2.5-fold reduction in elastic modulus. A three-stage sorption model was applied, quantifying water diffusion, hydrolytic degradation, and leaching of polymer components. Morphological examinations using scanning electron microscopy and energy-dispersive X-ray spectroscopy revealed crystalline salt deposits forming preferentially at interlayer interfaces, contributing to accelerated structural deterioration. Differential scanning calorimetry further showed shifts in crystallization temperature and crystallinity, underscoring alterations in polymer structure due to degradation. These results demonstrate that bulk part dimensions and 3D printing parameters critically influence degradation pathways, emphasizing the necessity of bulk-scale studies to predict real-world degradation behavior in marine environments accurately.

This study explores an advanced approach to enhancing the antimicrobial efficacy and hydrophilicity of poly(lactic acid) (PLA) scaffolds through the strategic incorporation of cellulose nanocrystals (CNC). The compatibility between these biodegradable polymers was investigated to optimize antimicrobial agent release while preserving structural integrity. PLA nanocomposites incorporating the antimicrobial agents curcumin (Cur) or polyhexamethylene biguanide (PHMB) were fabricated using three distinct electrospinning-based methodologies. The antibacterial properties were assessed via a disc diffusion test against five bacterial strains: Escherichia coli, Escherichia coli B+, Lactobacillus salivarius, Streptococcus sanguinis, and Streptococcus mutans. In addition, drug release experiments were conducted to determine the diffusion kinetics in a simulated blood serum medium, demonstrating sustained drug release for up to 98 hours. PHMB demonstrated potent antibacterial activity, while curcumin primarily exhibited bacteriostatic effects. The thermal stability of the nanocomposites exhibited an increase of up to 41 °C in the maximum degradation temperature. The mechanical properties were assessed to further examine the interactions between CNC and PLA and the possibility to reshape the materials for different delivery approaches. The findings underscore the crucial role of CNC in modulating the interaction between PLA and antimicrobial agents, making it a promising candidate for biomedical applications requiring controlled drug release. This study provides valuable insights into the structural, thermal, and antibacterial performance of CNC–PLA nanocomposites, establishing a strong foundation for the development of advanced biodegradable materials for drug delivery and antimicrobial applications.

Biodegradable and bio-based polymers, including polyhydroxyalkanoate (PHA), polylactic acid (PLA), and poly(butylene succinate-co-adipate) (PBSA), stand out as sustainable alternatives to traditional petroleum-based plastics for a wide range of consumer applications. Studying binary and ternary blends is essential to exploring the synergistic combinations and efficiencies of three distinct biopolyesters. A comprehensive evaluation of melt-extruded binary and ternary polymer blends of PHA, PLA, and PBSA was conducted. Scanning electron microscopy (SEM) analyses revealed a heterogeneous morphology characteristic of immiscible blends, with a predominant spherical inclusion morphology observed in the majority of the blends. An increased PBSA concentration led to an elevation in melt viscosity and elasticity across both ternary and binary blends. An increased PHA content reduced the viscosity, along with both storage and loss moduli in the blends. Moreover, a rise in PHA concentration within the blends led to increased crystallinity, albeit with a noticeable reduction in the crystallization temperature of PHA. PLA retained amorphous structure in the blends. The resultant bio-based blends manifested enhanced rheological and calorimetric traits, divergent from their pure polymer counterparts, highlighting the potential for optimizing material properties through strategic formulation adjustments.