Search Results (44)

In an effort to reduce global dependence on fossil-based polymers and advance toward a more sustainable materials industry, research over recent decades has increasingly focused on the development of bio-based polymers and broadening their potential applications. Within this context, the present study investigates nanocomposites based on poly(butylene succinate-co-butylene adipate) (PBSA), reinforced with two types of nanofillers: silicon dioxide nanoparticles (SiO₂ NPs) and cellulose nanofibrils (CNFs). The main objective of this work is to examine how the morphology, geometry, and chemical nature of the nanofillers influence the thermal, mechanical, and barrier properties of PBSA, as well as its biodegradability. For each nanofiller, three formulations were prepared, containing 1, 2, and 5 wt% of filler, respectively. Scanning electron microscopy (SEM) analysis confirmed good dispersion and minimal aggregation in the SiO₂-based systems, whereas marked aggregation was observed in the CNF-based samples. Thermal analysis indicated that the intrinsic thermal properties of neat PBSA were largely preserved. Mechanical testing revealed improvements in both the elastic modulus and elongation at break for most nanocomposite samples. In particular, CNFs provided the most consistent reinforcing effect, with enhancements of approximately 40% in the elastic modulus (495.4 vs. 356.4 GPa in neat PBSA) and 52% in elongation at the break (185.1 vs. 122.0% in neat PBSA) with 5 wt% loading. Additionally, the incorporation of nanofillers did not alter the surface hydrophilicity, but it did improve the oxygen barrier performance and enhanced disintegration under composting conditions. Overall, these findings demonstrate the promising potential of PBSA-based nanocomposites for sustainable rigid packaging applications. Full article

The environmental impact of petroleum-based plastics has accelerated the search for sustainable alternatives in food packaging. Polylactic acid (PLA), a biobased and compostable polymer, is among the most promising candidates, yet its inherent brittleness and poor moisture barrier limit its application in high-humidity contexts such as dairy packaging. This study investigates immiscible PLA/poly(butylene succinate-co-adipate) (PBSA) blend films as potential biobased packaging materials for perishable foods. Even if these blends have been already studied, limited attention has been given to the systematic characterization of the baseline barrier properties of unmodified PLA/PBSA blends in contact with liquid dairy products. Four blend ratios (PLA/PBSA = 30/70, 40/60, 50/50, 60/40 wt%) were prepared via micro-compounding and compression molding. The films were characterized through melt flow analysis, FTIR, SEM, DSC, DMTA, and tensile testing to evaluate their thermal, morphological, and mechanical properties. Crucially, moisture barrier performance was assessed under simulated dairy conditions by sealing fresh whey at 4 °C and monitoring weight loss over 30 days. Results revealed that while tensile strength and storage modulus (E’) decreased nearly linearly with increasing PBSA content, elongation at break exhibited a non-linear trend, highlighting the complex interplay between blend morphology and mechanical behavior. The study provides a baseline understanding of neat PLA/PBSA blends in contact with liquid dairy, identifying the most promising formulations for future scale-up. These findings contribute to the development of biodegradable packaging systems tailored for refrigerated, high-moisture food applications Full article

Home-compostable, biobased films were developed by blending poly(lactic acid) (PLA) with poly(butylene succinate-co-adipate) (PBSA). Among the formulations, the PLA/PBSA 60/40 blend demonstrated strong potential for industrial film production due to its enhanced flexibility and tear resistance. Thanks to their thermoplastic nature, these films can be applied to various substrates—such as paper or paperboard—and are easily recyclable within industrial processing environments. In this study, nanostructured clay and talc were incorporated into PLA/PBSA 60/40-based films to produce composites, which were evaluated for their effectiveness in limiting the diffusion of moisture from high-humidity soft cheeses. The materials’ melt fluidity and tensile properties were also characterized, and the composite morphology was examined using electron microscopy. The results revealed that the filler type significantly affected both the morphological structure and barrier performance, highlighting the critical role of material composition in the development of effective and environmentally sustainable packaging solutions. The biobased PLA/PBSA (60/40) films, particularly those filled with talc, exhibited high processability, flexibility, and effectiveness as a moisture barrier for dairy packaging. Although not yet feasible as a direct LDPE substitute without increasing their thickness, their low mass loss points to their strong potential for sustainable applications—especially when paired with paperboard in rigid packaging. Full article

This study systematically investigates the impact of hydrolytic degradation on the crystallization kinetics and morphology of poly(butylene succinate-co-adipate) (PBSA). Gel Permeation Chromatography (GPC) confirmed extensive chain scission, significantly reducing the polymer’s weight-average molecular weight (M_w from ~103,000 to ~16,000 g/mol) and broadening its polydispersity index (PDI from ~2 to 7 after 64 days). Differential scanning calorimetry (DSC) analysis revealed that hydrolytic degradation dramatically accelerated crystallization rates, reducing crystallization time roughly 10-fold (e.g., from ~3000 s to ~300 s), and crystallinity increased from 34% to 63%. Multiple melting peaks suggested the presence of lamellae with varying thicknesses, consistent with the Gibbs–Thomson equation. Isothermal crystallization kinetics were evaluated using the Avrami equation (with n ≈ 3), reciprocal half-time of crystallization, and a novel inflection point slope method, all confirming accelerated crystallization; for instance, the slope increased from 0.00517 to 0.05203. Polarized optical microscopy (POM) revealed evolving spherulite morphologies, including hexagonal and flower-like dendritic spherulites with diamond-shape ends, while wide-angle X-ray diffraction (WAXD) showed a crystallization range shift to higher temperatures (e.g., from 72–61 °C to 82–71 °C) and a 14% increase in crystallite diameter, aligning with increased melting point and lamellar thickness and overall increased crystallinity. Full article

This study investigates the impact of hydrolysis on the crystallization behavior of poly(butylene succinate-co-adipate) (PBSA), a biodegradable polyester. Hydrolysis was conducted in a controlled environment using phosphate-buffered saline at 70 °C to isolate the impact of hydrolytic degradation on the polymer’s properties. The consequent changes in molecular weight characteristics were tracked using gel permeation chromatography (GPC), revealing a decrease in both weight average molecular weight (M_w) and an increase in polydispersity index (PDI) as hydrolysis progressed. The thermal behavior of PBSA during hydrolysis was thoroughly investigated using differential scanning calorimetry (DSC), which demonstrated significant changes in melting temperature (T_m), glass transition temperature (T_g), and crystallinity (X). These changes in T_m and T_g suggest a change in copolymer composition, likely due to the greater susceptibility of the adipic acid unit to hydrolysis compared to the succinic acid unit. Furthermore, polarized optical microscopy (POM) was employed to observe the morphological evolution of PBSA, showing a transition from spherulitic structures in the early stages of hydrolysis to dendritic structures with prolonged hydrolysis time. The decrease in nucleation activity led to a reduction in the number of spherulites, which in turn allowed the remaining spherulites to grow larger. Full article

In this work, by-products from insect farming valorisation are proposed as filler in biocomposite production, with relevant biodegradation in compost and valuable thermal and mechanical properties. Thus, we report on the preparation, properties, and biodegradability in compost of composites based on Poly(butylene succinate-co-adipate) (PBSA) and Poly(3-hydroxybutyrate-3-hydroxyvalerate) (PHB-HV) (70/30% by weight as a polymeric matrix, with filler from insect exoskeleton (I) up to 15% by weight in the 85% by weight of polymeric matrix. The insect biomass was a by-product obtained from grinding the insect’s post-protein extraction dry exoskeleton. The composites were produced by melt extrusion and characterised in terms of processability, thermal stability, morphology, and mechanical properties to select formulations optimised for injection moulding processing. The optimised composites (PBSA/PHB-HV) with 15% by weight of filler were used to produce pots by injection moulding on an industrial scale extruder. Selected formulations were tested for biodegradability in compost, which evidenced the relevance of insect exoskeleton filler for meeting the requirements for the disintegration of rigid items. This paper presents a sustainable option for valorising the insect exoskeleton residue that remained after protein extraction for animal feed production and reducing the production cost of PBSA/PHB-HV-based composites without compromising the mechanical properties for application as rigid items in agriculture, all while promoting biodegradability in industrial compost. Full article

Plastics play a key role in every sector of the economy, being used in the manufacturing of products in the fields of health, food packaging, and agriculture. Their mismanagement poses a serious threat to ecosystems and, in general, to human life. For this reason, particular attention has been paid in the last decade to the use of biodegradable polymers (BPs) as an alternative to classic plastics. In this study, we aimed to identify bacterial strains able to colonize the surface of five BPs: poly(butylene succinate) (PBS), poly(butylene succinate-co-butylene adipate) (PBSA), poly(ε-caprolactone), (PCL), poly(3-hydroxybutyrate) (PHB), and poly(lactic acid) (PLA). For this experiment, mesocosms were designed ad hoc to mimic the conditions in which the polymers can be found in marine environments: i. suspended in the water column; ii. laying over gravel; and iii. under gravel. Four bacterial samples were taken (3, 4, 10, and 12 months from the start of the experiment) from five BPs incubated in the above-mentioned three conditions. Our results demonstrated that bacteria belonging to the Proteobacteria, Actinobacteria, Firmicutes, Bacillota, Bacteroidota, and Cyanobacteria phyla were the most frequent colonizers of the surfaces of the five polymers under analysis, and could be responsible for their degradation, resulting in the evolution of strategies to degrade plastics through the secretion of specific enzymes. Full article

The depletion of fossil fuels and environmental concerns have driven the development of sustainable materials, including bio-based and biodegradable plastics, as alternatives to conventional plastics. Although these plastics aid in waste management and climate change mitigation, their vulnerability to oxidative degradation impacts their longevity, durability, and performance. Natural antioxidants such as tocopherols, flavonoids, and tannins, extracted from plants or agri-food waste, present a sustainable alternative to synthetic stabilizers by enhancing the oxidative thermal stability of polymers like poly(lactic acid) (PLA), poly(butylene succinate) (PBS), poly(butylene succinate-adipate) (PBSA), poly(butylene adipate-co-terephthalate) (PBAT), poly(hydroxyalkanoate) (PHA), and starch-based materials. This review highlights recent advances in bio-based plastics stabilized with natural antioxidants, their mechanisms of action, and their role in improving material properties for applications like packaging. Additionally, it explores their impact on recycling processes, advancements in composite production techniques, and future research directions. Bioplastics can achieve enhanced performance, reduce waste, and support a circular economy by incorporating natural antioxidants. Full article

In the present study, the adsorption of arsenic(V) and cadmium(II) onto microplastics from poly(butylene succinate-co-butylene adipate) (PBSA) and low-density polyethylene (LDPE) plastic mulch films was investigated through batch experiment. The surface morphology and elemental composition of soil and microplastics were analyzed with scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy (SEM-EDX) and Fourier-transform infrared (FTIR) spectroscopy. The results show that the adsorption of As(V) and Cd(II) on microplastics led to surfaces with coarseness and more cracks, and many small particles. Under the conditions added with 100 pieces of microplastic, PBSA enhanced the adsorption capacity of As(V) (from 0.43 to 0.49 mg/g), and LDPE increased the adsorption of Cd(II) (from 0.174 to 0.176 mg/g) due to the “superimposed effect” caused by hydrogen bonds. Conversely, LDPE reduced the adsorption of As(V) (from 0.44 to 0.40 mg/g) due to a “dilution effect” of PE. Particularly, PBSA exhibited an insignificant effect on the adsorption of Cd(II) in soil during the present study. Overall, our findings provide new insights into the impacts of microplastics on the fate and behavior of heavy metals in the soil system. Full article

Biobased plastics are fully or partially made from biological resources but are not necessarily biodegradable or compostable. Poly (lactic acid) (PLA), one of the most diffused bioplastics, is compostable in industrial environments, but improving degradation in home composting conditions, in soil and in seawater could be beneficial for improving its end of life and general degradability. Blends obtained by the extrusion of PLA with different amounts of poly (butylene succinate-co-adipate) (PBSA) or poly (caprolactone) (PCL) were characterized in terms of their home composting, soil, marine and freshwater biodegradation. The blending strategy was found to be successful in improving the home compostability and soil compostability of PLA. Thanks to the correlations with morphological characterization as determined by electron microscopy, it was possible to show that attaining an almost co-continuous phase distribution, depending on the composition and melt viscosity of the blend components, can enhance PLA degradation in home composting conditions. Tests in marine and freshwater were also performed, and the obtained results showed that in marine conditions, pure PLA is degradable. A comparison of different tests evidenced that salt dissolved in marine water plays an important role in favoring PLA’s degradability. Full article

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is a very promising biodegradable copolyester of high interest in food packaging. Its inherent brittleness and narrow processing window make it necessary to blend it with flexible biopolyesters, such as poly(butylene succinate-co-adipate) (PBSA). However, the resultant biopolyester blends are thermodynamically immiscible, which impairs their performance and limits their applications. This study is the first to explore the use of poly(butylene succinate-co-adipate) grafted with maleic anhydride (PBS-g-MAH) as a novel reactive additive to compatibilize PHBV/PBSA blends. The compatibilizer was prepared by a reactive melt-mixing process of PBSA and maleic anhydride (MAH) using dicumyl peroxide (DCP) as an organic radical initiator, achieving a grafting degree (G_d) of 5.4%. Biopolyester blend films were thereafter prepared via cast extrusion and their morphological, thermal, mechanical, and barrier properties were characterized. Compatibilization by PBSA-g-MAH was confirmed by observing an improved phase interaction and lower dispersed domain sizes in the blends with 15 wt% PBSA. These compatibilized PHBV/PBSA blends were thermally stable up to 285 °C, showed enhanced ductility and toughness, as well as providing an improved barrier against water and limonene vapors and oxygen. These findings suggest that the use of MAH-grafted biopolyesters can represent an effective strategy to improve the properties of biopolyester blends and open up new opportunities for the application of PHBV-based formulations for food packaging. Full article

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. Full article

The development of fully renewable and biodegradable composites for short-term applications was pursued by combining a compatibilized poly(lactic acid) (PLA)/poly(butylene succinate-co-adipate) (PBSA) (60:40 wt:wt) blend with coffee silver skin (CSS), an industrial byproduct from coffee processing. An epoxy-based reactive agent (Joncryl ADR-4468) was added as a compatibilizer. CSS was incorporated at 5, 10, and 20 wt% in the blend both in the as-received state and after a simple thermal treatment in boiling water, which was performed to mitigate the negative impact of this filler on the rheological and mechanical properties of the blend. The CSS treatment effectively increased the filler degradation temperature of 30–40 °C, enabling stable melt processing of the composites. It also improved filler–matrix adhesion, resulting in enhanced impact properties (up to +172% increase in impact energy compared to the untreated filler). Therefore, treated CSS demonstrated potential as an effective green reinforcement for PLA/PBSA blends for rigid packaging applications. Future works will focus on studying suitable surface modification of CSS to further increase the interfacial interaction and the tensile quasi-static properties, to fully exploit the capabilities of this renewable material toward the development of eco-friendly composites. Full article

The emergence of bioplastics presents a promising solution to the environmental impact of the plastics industry. Bioplastics are engineered to degrade in aquatic or soil environments. However, not all bioplastics are completely biodegradable, and some, like petrochemical-based plastics, may contribute to plastic pollution. The biodegradability of bioplastics is significantly different in different environmental conditions such as soil, marine, and composting environments. At the same time, bioplastics produced from natural resources contain a mixture of known and unknown materials and show 32% cytotoxicity, 42% oxidative stress, 67% baseline toxicity, and 23% antiandrogenicity in bioassays. The extensive biodegradation of bioplastics in soil can also change the soil nutrients, leading to eutrophication or stunted plant growth. However, many concerns have arisen, according to which bioplastics may not be an alternative option for global plastic pollution in the long run, and limited studies focus on this scenario. This review aims to provide a comprehensive overview of the biodegradation of bioplastics in different environmental conditions and by microorganisms and their ecotoxicological impacts on soil and marine health. In conclusion, while bioplastics have the potential to be a sustainable alternative to conventional plastics, it is essential to address concerns regarding their complete biodegradability and toxicity. Therefore, sustainable methods must be used for their production and biodegradation to ensure a positive impact on the environment. Full article

Genome mining of Streptomyces exfoliatus DSMZ 41693 has allowed us to identify four different lipase-encoding sequences, and one of them (SeLipC) has been successfully cloned and extracellularly expressed using Rhodococcus sp. T104 as a host. SeLipC was purified by one-step hydrophobic interaction chromatography. The enzyme is a monomeric protein of 27.6 kDa, which belongs to subfamily I.7 of lipolytic enzymes according to its phylogenetic analysis and biochemical characterization. The purified enzyme shows the highest activity at 60 °C and an optimum pH of 8.5, whereas thermal stability is significantly improved when protein concentration is increased, as confirmed by thermal deactivation kinetics, circular dichroism, and differential scanning calorimetry. Enzyme hydrolytic activity using p-nitrophenyl palmitate (pNPP) as substrate can be modulated by different water-miscible organic cosolvents, detergents, and metal ions. Likewise, kinetic parameters for pNPP are: K_M = 49.6 µM, k_cat = 57 s⁻¹, and k_cat/K_M = 1.15 × 10⁶ s⁻¹·M⁻¹. SeLipC is also able to hydrolyze olive oil and degrade several polyester-type polymers such as poly(butylene succinate) (PBS), poly(butylene succinate)-co-(butylene adipate) (PBSA), and poly(ε-caprolactone) (PCL). Moreover, SeLipC can catalyze the synthesis of different sugar fatty acid esters by transesterification using vinyl laurate as an acyl donor, demonstrating its interest in different biotechnological applications. Full article