Search Results (70)

Biopolymers and bio-based plastics, such as polylactic acid (PLA) and polybutylene succinate (PBS), are recognized as environmentally friendly materials and are widely used, especially in the packaging industry. The purpose of this study was to assess the degradation of PLA- and PBS-based formulations in the forms of granules and films under controlled composting conditions at a laboratory scale. Biodegradation tests of bio-based materials were conducted under controlled aerobic conditions, following the standard EVS-EN ISO 14855-1:2012. Scanning electron microscopy (SEM) was performed using a high-resolution Zeiss Ultra 55 scanning electron microscope to analyze the samples. After the six-month laboratory-scale composting experiment, it was observed that the PLA-based materials degraded by 47.46–98.34%, while the PBS-based materials exhibited a final degradation degree of 34.15–80.36%. Additionally, the PLA-based compounds displayed a variable total organic carbon (TOC) content ranging from 38% to 56%. In contrast, the PBS-based compounds exhibited a more consistent TOC content, with a narrow range from 53% to 54%. These findings demonstrate that bioplastics can contribute to reducing plastic waste through controlled composting, but their degradation efficiency depends on the material composition and environmental conditions. Future efforts should optimize bioplastic formulations and composting systems while developing supportive policies for wider adoption. Full article

The development of bio-based and biodegradable materials is critical for reducing environmental impact and addressing global challenges associated with the extensive use of plastics in packaging applications. In this study, linear oligomers of butylene succinate (OBS) with three different molecular weights were synthesized using succinic acid (SA) and 1,4-butanediol (BDO), both monomers derived from biomass. The synthesized fully bio-based OBS samples were characterized in terms of their molecular structure, degree of polymerization, crystallinity, and thermal properties, showcasing their potential as additives for biopolymers in food packaging. Oligomers with weight-average molecular weight (M_w) values of 2050 g·mol⁻¹ (OBS-L), 16,150 g·mol⁻¹ (OBS-M), and 33,147 g·mol⁻¹ (OBS-H), and Ð values in the 1.7–1.8 range were successfully synthesized. The results showed that the thermal degradation stability of OBS slightly increased, while the crystallinity decreased with increasing molecular weight. Furthermore, the analysis of the evolution of the lattice parameters suggested that oligomers with shorter chains favored crystal organization, resulting in a crystal unit cell with denser packing. Full article

This study explores sustainable foamed polyester materials derived from natural or bio-based building blocks, including succinic, glutaric, and adipic acids, combined with trimethylolpropane and pentaerythritol. By precisely tuning the ratio of functional groups, the resulting polymers contain minimal free functionalities, leading to lower hygroscopicity and enhanced stability. The reaction is monitored by tracking the mass loss associated with water formation, the primary condensation by-product, which reveals a first-order kinetic behaviour. Infrared spectroscopy indicates that foaming occurs in a narrow time window, while esterification begins earlier and continues afterwards. Thermogravimetric analysis confirms thermal stability up to ~400 °C, with complete decomposition at 500 °C and no residue. Scanning electron microscopy images of test specimens with varying densities reveal dense, microporosity-free cell walls in both materials, indicating a homogeneous polymer matrix that contributes to the overall stabilisation of the foam structure. In flammability tests, the foams resist ignition during two 10 s methane flame exposures and, under prolonged flame, burn 40 times more slowly than conventional foams. These results demonstrate a modular system for creating bio-based foams with tunable properties—from soft and elastic to rigid—suitable for diverse applications. The materials offer a sustainable alternative to petrochemical foams while retaining excellent mechanical and thermal properties. Full article

The increasing demand for sustainable mining practices has driven the development of environmentally friendly reagents for mineral processing. This study investigates vitamin E sodium succinate (VE_SS), a novel bio-based collector, for its potential in hematite flotation. The performance of VE_SS was benchmarked against sodium oleate (NaOL), a widely used conventional collector in mineral processing. To assess the flotation performance of VE_SS, micro-flotation experiments were conducted using hematite, sourced from a mine, and silica, a common associated gangue mineral. These tests were complemented by comprehensive surface characterizations, including contact angle measurements, zeta potential analysis, Fourier-transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS), to investigate the adsorption mechanisms of VE_SS in comparison to NaOL. The results demonstrate that VE_SS effectively enhances hematite recovery, achieving levels comparable to NaOL. Furthermore, VE_SS exhibited reduced sensitivity to pH, addressing a key limitation of NaOL, which performs well in neutral to alkaline conditions but shows significantly lower recovery under acidic pH. These findings highlight the potential of VE_SS as a bio-based alternative to conventional collectors, contributing to the advancement of more sustainable mineral processing practices. Full article

Nanoarchitectonics influences the properties of objects at micro- and even macro-scales, aiming to develop better structures for protection of product. Although its applications were analyzed in different areas, nanoarchitectonics of food packaging—the focus of this review—has not been discussed, to the best of our knowledge. The (A) structural and (B) functional hierarchy of food packaging is discussed here for the enhancement of protection, extending shelf-life, and preserving the nutritional quality of diverse products including meat, fish, dairy, fruits, vegetables, gelled items, and beverages. Interestingly, the structure and design of packaging for these diverse products often possess similar principles and methods including active packaging, gas permeation control, sensor incorporation, UV/pulsed light processing, and thermal/plasma treatment. Here, nanoarchitechtonics serves as the unifying component, enabling protection against oxidation, light, microbial contamination, temperature, and mechanical actions. Finally, materials are an essential consideration in food packaging, particularly beyond commonly used polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polystyrene (PS), and polyvinyl chloride (PVC) plastics, with emphasis on biodegradable (polybutylene succinate (PBS), polyvinyl alcohol (PVA), polycaprolactone (PCL), and polybutylene adipate co-terephthalate (PBAT)) as well as green even edible (bio)-materials: polysaccharides (starch, cellulose, pectin, gum, zein, alginate, agar, galactan, ulvan, galactomannan, laccase, chitin, chitosan, hyaluronic acid, etc.). Nanoarchitechnotics design of these materials eventually determines the level of food protection as well as the sustainability of the processes. Marketing, safety, sustainability, and ethics are also discussed in the context of industrial viability and consumer satisfaction. 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

The importance of the valorization of industrial by-products has led to increasing research into their reuse. In this research, the innovative by-product okara oat flour, derived from the vegetable beverage industry, was studied. Oat okara sourdough was also produced and evaluated. The microbiological identification and typing involved bacterial and yeast isolates from both flour and sourdough. Untargeted metabolomics allowed the identification of biomarkers of fermented flour, such as phenolic classes, post-fermentation metabolites, fatty acids, and amino acids. The microorganisms most found were Weissella confusa, Enterococcus faecium, Pediococcus pentosaceus, and Pichia kudriavzevii, while Saccharomyces cerevisiae appeared only at the end of the sourdough’s back-slopping. Untargeted metabolomics identified a total of 539 metabolites, including phenolic compounds, lipids, amino acids, and organic acids. An increase in polyphenols released from the food matrix was detected, likely because of the higher bio-accessibility of phenolic metabolites promoted by microbial fermentation. Fermentation led to an increase in isoferulic acid, p-coumaric acid, sinapic acid, and a decrease in amino acids, which can be attributed to the metabolism of lactic acid bacteria. Some key markers of the fermentation process of both lactic acid bacteria and yeast were also measured, including organic acids (lactate, succinate, and propionate derivatives) and flavor compounds (e.g., diacetyl). Two bioactive compounds, such as gamma-aminobutyric acid and 3-phenyl-lactic acid had accumulated at the end of fermentation. Taken together, our findings showed that oat okara flour can be considered an excellent raw material for formulating more sustainable and functional foods due to fermentation promoted by autochthonous microbiota. Full article

In recent years, numerous researchers have incorporated plant fibers into polymers to alter the thermal and mechanical properties of materials. Grapevines, considered agricultural waste, have led to burdens for farmers and environmental challenges due to their mass production. This study aims to reduce the brittleness of polylactic acid (PLA) by adding polybutylene succinate (PBS) as a toughening agent and employing grapevine fiber (GVF) as a biomass filler. Additionally, the influence of GVF, toughening agents, compatibilizers, and lubrication agents on the tensile strength, heat deflection temperature (HDT), and impact strength of the composites was examined. The findings revealed that the addition of 10% GVF and 5% PBS increased the impact and tensile strengths of PLA from 17.47 J/m and 49.74 MPa to 29.7 J/m and 54.46 MPa, respectively. Moreover, the HDT of the composites exceeded 120 °C when the GVF content was more than 40 wt%. Additionally, the inclusion of a compatibilizer and a lubrication agent enabled the composite containing 30% GVF to achieve tensile and impact strengths of 45.30 MPa and 25.52 J/m, respectively. Consequently, these GVF/PLA green bio-composites not only improve the mechanical and thermal properties of PLA but also promote the reuse of waste grapevines. Full article

Fiber-reinforced composites (FRCs) represent a promising class of engineering materials due to their mechanical performance. However, the vast majority of FRCs are currently manufactured using carbon and glass fibers, which raises concerns because of the difficulties in recycling and the reliance on finite fossil resources. On the other hand, the use of natural fibers is still hampered due to the problems such as, e.g., differences in polarity between the reinforcement and the polymer matrix components, leading to a significant decrease in composite durability. In this work, we present a natural fiber-reinforced composite (NFRC), incorporating plasma pre-treated flax fibers as the reinforcing element, thermoplastic polylactic acid (PLA) as a matrix, and a key point of the current study—a thermoset coating based on epoxidized linseed oil for adhesion improvement. Using atmospheric plasma-jet treatment allows for increasing the fiber’s surface energy from 20 to 40 mN/m. Furthermore, a thermoset coating layer based on epoxidized linseed oil, in conjunction with dodecyl succinic anhydride (DDSA) as a curing agent and 2,4,6-tris(dimethyl amino methyl) phenol (DMP-30) as a catalyst, has been developed. This coated layer exhibits a decomposition temperature of 350 °C, and there is a substantial increase in the dispersive surface-energy part of the coated flax fibers from 8 to 30 mN/m. The obtained natural fiber-reinforced composite (NFRC) was prepared by belt-pressing with a PLA film, and its mechanical properties were evaluated by tensile testing. The results showed an elastic modulus up to 18.3 GPa, which is relevant in terms of mechanical properties and opens up a new pathway to use natural-based fiber-reinforced bio-based materials as a convenient approach to greener FRCs. 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

Biodegradable polymers and their blends have been advised as an eco-sustainable solution; however, the generation of microplastics (MPs) from their degradation in aquatic environments is still not fully grasped. In this study, we investigated the formation of bio-microplastics (BMPs) and the changes in the physicochemical properties of blown packaging films based on polylactic acid (PLA), polybutylene succinate (PBS) and a PBS/PLA 70/30 wt% blend after degradation in different aquatic media. The tests were carried out in two temperature/light conditions to simulate degradation in either warm water, under sunlight exposure (named Warm and Light—W&L), and cold deep water (named Cold and Dark—C&D). The pH changes in the aqueous environments were evaluated, while the formed BMPs were analyzed for their size and shape alongside with variations in polymer crystallinity, surface and mechanical properties. In W&L conditions, for all the films, the hydrolytic degradation led to the reorganization of the polymer crystalline phases, strong embrittlement and an increase in hydrophilicity. The PBS/PLA 70/30 blend exhibited increased resistance to degradation with respect to the neat PLA and PBS films. In C&D conditions, no microparticles were observed up to 12 weeks of degradation. Full article

The current level of packaging consumption imposes a need to fabricate single-use food packaging with renewable and compostable materials, such as bio-polyesters (e.g., polylactic acid, PLA and polybutylene succinate, PBS) or cellulose, but their use is still problematic. Fabrication of bio-compostable composites can specifically address impeding challenges, and adhesive lamination, achieved with compostable glue, is becoming more and more popular with respect to the less versatile hot lamination. In this context, plasma activation, a chemical-free oxidation technique of a material’s surface, is used to increase the affinity of three different biomaterials (cellulose, PLA and PBS) toward a compostable polyurethane adhesive to decrease its amount by gluing bio-polyesters to cellulose. Optical Microscopy reveals activation conditions that do not affect the integrity of the materials, while Water Contact Analyses confirm the activation of the surfaces, with contact angles decreased to roughly 50 deg in all cases. Unexpectedly, ζ-potential analyses and subtractive infrared spectroscopy highlight how the activation performed superficially etches cellulose, while for both PLA and PBS, a general decrease in surface potential and an increase in superficial hydroxyl group populations confirm the achievement of the desired oxidation. Thus, we rationalize continuous activation conditions to treat PLA and PBS and to glue them to neat cellulose. While no beneficial effect is observed with activated PLA, bi-laminate composites fabricated with activated PBS fulfill the benchmark for adhesion strength using less than before, while oxygen permeation analyses exclude plasma-induced etching even at a nanoscale. Full article

Layered double hydroxides (LDHs) are fascinating clay-like materials that display versatile properties, making them an extremely fertile playground for diverse applications, ranging from bio-compatible materials to the pharmaceutical industry to catalysis and photocatalysis. When intercalating organic and bio-organic species between the inorganic layers, such materials are named hybrid LDHs. The structure–property relation in these systems is particularly relevant, since most of the properties of the materials may be fine-tuned if a comprehensive understanding of the microscopic structure in the interlamellar space is achieved, especially with respect to the reorganization under water uptake (swelling). In this work, we combined experiments and simulations to rationalize the behavior of LDHs intercalating three carboxylates, the general structure of which can be given as $\left[{\mathrm{Mg}}_4{\mathrm{Al}}_2{\left(\mathrm{OH}\right)}_{12}\right]{\mathrm{A}}^{2-}$·${\mathrm{XH}}_2$O (with ${\mathrm{A}}^{2-}$ = succinate, aspartate, or glutamate and X representing increasing water content). Following this strategy, we were able to provide an interpretation of the different shapes observed for the experimental water adsorption isotherms and for the evolution of the infrared carboxylate band of the anions. Apart from small differences, due to the different reorganization of the conformational space under confinement, the behavior of the two amino acids is very similar. However, such behavior is quite different in the case of succinate. We were able to describe the different response of the anions, which has a significant impact on the isotherm and on the size of the interlamellar region, in terms of a different interaction mechanism with the inorganic layer. Full article

Succinic acid is an essential component of the chemical industry. Traditionally produced from fossil resources, its sustainable production using renewable resources faces challenges due to the complexities of cultivation and purification. This study assessed the environmental impacts of succinic acid production from sugarcane through a life cycle analysis and compared it with three other scenarios: using sorghum, apple pomace, and the traditional chemical route. Employing the ReCiPe midpoint methodology with a cradle-to-gate approach, the analysis highlighted significant environmental impacts linked to the agricultural stage in the sugarcane process. The use of pesticides, fertilizers, and energy demand resulted in elevated impacts compared to other stages of the process. The other scenarios also presented strong contributions in the purification stages. The production from sugarcane proved advantageous compared to other scenarios, minimizing impacts in 6 out of 10 categories. It is evident that the selection of the correct biomass is crucial for process sustainability, and the use of second-generation inputs can help reduce impacts in the agricultural stage. However, advancements in the fermentation stage are necessary, along with a reduction in the complexity of the purification steps. This study emphasizes the potential of renewable succinic acid production from sugarcane juice in the Brazilian scenario. Utilizing this process could reduce succinic acid’s environmental impacts by 70% to 99% compared to the petrochemical route. The process should be considered as a sustainable alternative to be included in the portfolio of biorefineries, enhancing factory profitability. Full article

The physical and mechanical properties of novel bio-based polymer blends of polylactic acid (PLA), poly(butylene succinate) (PBS), and poly (butylene adipate-co-terephthalate) (PBAT) with various added amounts of nanohydroxyapatite (nHA) were investigated in this study. The formulations of PLA/PBS/PBAT/nHA blends were divided into two series, A and B, containing 70 or 80 wt% PLA, respectively. Samples of four specimens per series were prepared using a twin-screw extruder, and different amounts of nHA were added to meet the regeneration needs of bone graft materials. FTIR and XRD analyses were employed to identify the presence of each polymer and nHA in the various blends. The crystallization behavior of these blends was examined using DSC. Tensile and impact strength tests were performed on all samples to screen feasible formulations of polymer blends for bone graft material applications. Surface morphology analyses were conducted using SEM, and the dispersion of nHA particles in the blends was further tested using TEM. The added nHA also served as a nucleating agent aimed at improving the crystallinity and mechanical properties of the blends. Through the above analyses, the physical and mechanical properties of the polymer blends are reported and the most promising bone graft material formulations are suggested. All blends were tested for thermal degradation analysis using TGA and thermal stability was confirmed. The water absorption experiments carried out in this study showed that the addition of nHA could improve the hydrophilicity of the blends. Full article