Vincenzo Titone

Biocomposites offer a key solution for managing food waste and replacing non‐biodegradable plastics. In this study, grape pomace (GP) was incorporated at 10 and 20 wt.% into poly(butylene adipate‐co‐butylene terephthalate) (PBAT) and polylactide (PLA) through melt compounding to investigate the effect of the filler on different properties. The influence of GP on morphology, mechanical, thermal, and rheological properties was evaluated. The results revealed a strongly matrix‐dependent effect of GP. GP has opposite effects on viscosity: it increases in PBAT‐based composite (especially at 20% loading), but reduces it in PLA‐based ones. SEC analyses showed a progressive decrease in PLA molecular weight from Mw about 245,000 g mol ⁻¹ for neat PLA to ~147,000 g mol ⁻¹ for PLA/GP20, while only limited variations were observed for PBAT‐based samples. For both matrices, GP enhanced stiffness while reducing tensile strength and elongation at break. The comparative performance assessment provided the appropriate information for selecting the PBAT‐based biocomposite as the most suitable formulation for further degradation testing in compost. Degradation tests in compost (58°C, 90 days) demonstrate that GP accelerates disintegration kinetics with PBAT‐based biocomposites showing significantly higher weight loss and surface deterioration than neat PBAT. Grape pomace promotes microbial colonization and enzyme activity, specifically driven by Streptomyces thermoviolaceus and Bradyrhizobium elkanii , which accelerates PBAT depolymerization. Overall, GP effects depend on the polymer: it worsens PLA chain degradation during processing, whereas in PBAT it preserves molecular integrity while accelerating composting disintegration. Further studies measuring CO ₂ and O ₂ are needed to confirm ultimate biodegradation and mineralization.

The increasing environmental presence of microplastics and nanoplastics constitutes a critical concern for environmental integrity and public health, with notable repercussions across aquatic systems, terrestrial ecosystems, and both human and animal health. These particles—defined by their dimensions of less than 5 mm—mainly originate from direct production (primary microplastics) or from the breakdown of larger plastic materials (secondary microplastics) via degradation and fragmentation processes. Polymer blends currently represent an acknowledged contributor to this phenomenon, as they incorporate both a dispersed phase, already in the microplastic size range, and a continuous matrix that, upon degradation, generates further microparticles, thus acting as both primary and secondary sources of microplastics (and nanoplastics). Despite this, the actual behavior of polymer blends—especially those based on polyolefins and polyesters—remains underexplored. In the present study, two types of polyolefin/polyester blends, one with a compatibilizing agent and one without, were subjected to mechanical fragmentation and photo‐oxidative degradation in order to replicate the most common microplastic formation pathways. The results revealed that exposure to photo‐oxidation significantly increases the release of microplastics, whereas compatibilization markedly decreases this release, both in pristine and weathered samples. These results underscore the critical role of morphological characteristics and compatibilization strategies in influencing microplastics generation.

To the best of our knowledge, only a few studies have investigated the generation of micro‐ and nanoplastics from biodegradable polymers and polymer blends, likely due to their biodegradable nature and lower environmental persistence. Nevertheless, understanding their fragmentation behavior is crucial to clarify the effects of blend composition, processing conditions, and ageing on particle formation. In this study, poly(butylene succinate) (PBS) and poly(butylene adipate‐co‐terephthalate) (PBAT) were blended with and without the reactive compatibilizer Joncryl to evaluate the role of reactive compatibilization and the potential formation of microplastics. Spectroscopic, rheological, morphological, and mechanical characterizations were performed, together with mechanical fragmentation tests before and after ultraviolet (UV) irradiation. The results revealed significant morphological improvements in compatibilized blends, with an approximately 30% reduction in dispersed phase size. Enhanced rheological and mechanical properties were also observed, particularly in elongation at break (≈28% vs. 263%). From a sustainability perspective, no intentional microplastic release was detected. However, after 120 h of UV exposure, unintentional microplastic release occurred, with fragments smaller than 5 mm accounting for ≈16 wt% in compatibilized samples versus ≈22 wt% in uncompatibilized blends. Overall, Joncryl improved material performance while potentially reducing microplastic release.

From 2030, in line with the new directive issued by the European Union, manufacturers of plastic beverage bottles will have to include at least 30% recycled plastic, calculated as an average for all bottles placed on the market in each Member State. In this context, many companies and start‐ups are producing blends of virgin poly(ethylene terephthalate) with mechanically or chemically recycled poly(ethylene terephthalate). In this study, a monopolymer blend composed of virgin poly(ethylene terephthalate) and 30% mechanically recycled poly(ethylene terephthalate) was prepared and compared with a commercial blend containing 30% chemically recycled poly(ethylene terephthalate). Rheological (processability) and mechanical properties were evaluated. The results show that the monopolymer blend with 30% mechanically recycled poly(ethylene terephthalate) exhibits mechanical properties similar to the commercial blend, with percentage variations of approximately +10.9% for elastic modulus, +5.8% for tensile strength, and −13.6% for elongation at break. Furthermore, when reprocessed, the properties remain largely preserved. An additive model accurately predicts blend behavior, with deviations between experimental and theoretical values generally below 10%.

Biodegradable polymeric composites reinforced with natural fillers represent one of the most promising routes toward low-impact, circular, and resource-efficient materials. In recent years, a growing number of studies have focused on the valorization of plant- and animal-derived organic waste, ranging from agricultural residues and natural fibers to marine and livestock by-products. This review provides a comprehensive and comparative overview of these systems, analyzing the nature and origin of the waste-derived fillers, their pretreatments, processing strategies, and the resulting effects on mechanical, thermal, functional, and biodegradation properties. Particular attention is dedicated to the role of filler composition, morphology, and surface chemistry in governing interfacial adhesion and end-use performance across different polymeric matrices, including PLA, PCL, PBS, PHA, PHB, PBAT, and commercial blends such as Mater-Bi^®. The emerging applications of these biocomposites, such as packaging, additive manufacturing, agriculture, biomedical uses, and environmental remediation, are critically discussed. Overall, this work provides fundamental insights to support the development of the next generation of biodegradable materials, enabling the sustainable valorization of organic waste within a circular-economy perspective.

Biodegradable polymeric composites reinforced with natural fillers represent one of the most promising routes toward low-impact, circular, and resource-efficient materials. In recent years, a growing number of studies has focused on the valorization of plant- and animal-derived organic waste, ranging from agricultural residues and natural fibers to marine and livestock by-products. This review provides a comprehensive and compar-ative overview of these systems, analyzing the nature and origin of the waste-derived fillers, their pretreatments, processing strategies, and the resulting effects on mechanical, thermal, functional, and biodegradation properties. Particular attention is dedicated to the role of filler composition, morphology, and surface chemistry in governing interfacial adhesion and end-use performance across different polymeric matrices, including PLA, PCL, PBS, PHA, PHB, PBAT, and commercial blends such as Mater-Bi®. The emerging applications of these biocomposites, such as packaging, additive manufacturing, agri-culture, biomedical uses, and environmental remediation, are critically discussed. Overall, this work provides fundamental insights to support the development of the next generation of biodegradable materials enabling the sustainable valorization of organic waste within a circular-economy perspective.

The growing demand for sustainable materials is driving both academia and industry to replace conventional oil-based polymers with biodegradable alternatives

The amount of plastic waste released into the environment has prompted the scientific community to seek new strategies to tackle the problem. Among common pollutants, Polyethylene Terephthalate (PET) bottles are leading contributors, accounting for 30%–40% of plastic waste. However, recently, new recycling opportunities have been emerging, with academia and industry increasingly focusing on innovative approaches. One method that has boomed recently is solid‐state polycondensation (SSP), a process that, through the re‐gradation of recycled polymer, gives PET from bottles a second life, aiming for bottle‐to‐bottle recycling. This paper aims to characterize a recycled regraded PET sample in comparison with mechanically recycled PET, and to compare it with blends made from virgin and recycled PET bottles (monopolymer blends). This last strategy is commonly used in industry to reduce the environmental impact of plastic materials. All samples were characterized in shear and elongational flow, and tensile properties were measured and correlated with variations in molecular structure and morphology. The results showed that monopolymer blends of virgin and recycled PET exhibited tensile strengths of 39.4, 38.5, and 37.1 MPa and elongation at break of 319%, 310%, and 294%, at 10%, 25%, and 50%, respectively, while the regraded PET by SSP showed a tensile strength of 44.7 MPa and elongation at break of 218%, demonstrating that the monopolymer blend exhibits mechanical performance suitable for bottle production.

The addition of antimicrobial additives in packaging systems is becoming essential, and this study aimed to incorporate carvacrol (CRV) into Poly(lactic acid) (PLA)/Poly(butylene adipate‐co‐terephthalate) (PBAT) blends to investigate the effects of blend composition on the resulting material's properties, with a particular focus on CRV release kinetics and antibacterial activity. The materials are prepared via melt mixing and compression molding and are thoroughly characterized through mechanical, rheological, and wettability analyses. Tensile tests reveal that adding PBAT to PLA increases flexibility, reducing modulus by 26% and tensile strength by 60%, while elongation at break rises by 550%. Adding PLA to PBAT increases stiffness, with modulus rising by 128%, but tensile strength and elongation decrease by 62% and 70%, respectively. The CRV release profile revealed that the release rate can be modulated by altering the blend composition. In vitro evaluation of antibacterial activity shows that the polymers with high PBAT content and containing CRV inhibited the growth of Listeria monocytogenes to undetectable levels (−1). Overall, the results show that the blend formulation significantly influenced the material properties compared to the pure components, providing effective antibacterial activity against both pathogens.