Macromol

The growing concern for environmental sustainability has led to an increased interest in biodegradable materials derived from renewable resources. This study explores the innovative use of residual biomass from the green photosynthetic microalga Chlamydomonas reinhardtii, left over after polysaccharide extraction, as a natural filler in the development of the compostable protein-based material SP-Milk^®. The microalgal biomass was characterized using Fourier transform infrared spectroscopy (FTIR) and UV-Visible Spectroscopy to assess its chemical and structural composition. Subsequently, it was incorporated into a biodegradable protein matrix, and the resulting biocomposites were evaluated for mechanical and thermal properties. The results demonstrate that the incorporation of algal filler improves the mechanical strength and elasticity of the material while reducing its glass transition temperature, highlighting its potential for use in sustainable applications as a possible substitute for conventional plastics. The biocomposite materials developed, based on the protein-based material SP-Milk^® and residual microalgal biomass, are environmentally friendly, contributing to the reduction in pollution and the risks associated with plastic accumulation. Thus, this study offers a simple, effective, and sustainable strategy for the valorization of microalgal biomass, enabling the production of biodegradable materials with enhanced mechanical performance, suitable for applications such as sustainable packaging within a circular economy framework. Full article

Poly(propylene thiophenedicarboxylate) (PPTh) is a new type of fully biobased polyester with excellent thermal, mechanical, and barrier properties; however, its practical application has been seriously restricted by the relatively slow crystallization rate. To further improve the crystallization rate and broaden the potential application field of PPTh, PPTh/multi-walled carbon nanotubes (MWCNTs) composites were successfully synthesized via an in situ melt polycondensation process in this research. Low contents of MWCNTs were well dispersed in the PPTh matrix. MWCNTs significantly increased the melt crystallization temperature and isothermal crystallization rate of PPTh, indicating the effective heterogeneous nucleating agent role. PPTh/MWCNTs composites displayed the same crystal structure as PPTh. In addition, the introduction of MWCNTs significantly enhanced both the Young’s modulus and the tensile strength of PPTh. From a sustainable viewpoint, biobased PPTh/MWCNTs composites reported in this research were of significant importance and interest as they showed remarkably improved crystallization rates and mechanical properties. Full article

Conventional thermoplastic polymer composites are produced using energy-intensive equipment. From an environmental perspective, reducing energy and material consumption, as well as selecting polymers and fillers that biodegrade without harmful consequences for the environment, is considered good practice. In this work, polyvinyl alcohol (PVOH), a biodegradable and water-soluble polymer, was compounded with 30 w%, 40 µm long cellulose fibres. Conventional melt blending production and innovative cold processing were compared from a tensile testing, thermogravimetric, and life cycle assessment (LCA) perspective through primary data collection. The granule production process significantly affects the mechanical performance of injected samples, with a 23.4% drop in tensile strength and an increase of 67.9% in elongation at break. The thermogravimetric analysis reported slight differences due to an additional thermal process involved in the melt blending of PVOH. From an LCA perspective, the innovative cold blending of PVOH-based composites drops all environmental indicators by 58–92%, maximizing the reduction of the “Water use” indicator. The most impactful production phase in the analysed production processes was drying, accounting for 46% and 85% of the conventional melt blending and innovative cold-blending processes, respectively. Full article

The escalating production of virgin plastics has resulted in an unprecedented generation of microplastics (MPs), posing significant environmental and health risks. Biodegradable plastics have emerged as an alternative, but their degradation also releases microplastic-sized particles, referred to as biodegradable microplastics (BMPs). This review evaluates the current understanding of BMPs, focusing on their environmental fate, degradation kinetics, and comparative persistence relative to conventional MPs. The degradation process of biodegradable plastics involves sequential abiotic and biotic mechanisms, with factors such as polymer chemistry, geometry, and environmental conditions influencing BMPs’ formation and mineralization. Studies highlight the temporal advantage of BMPs, which exhibit significantly shorter lifetimes than traditional MPs; however, their environmental impact remains context-dependent, particularly in soil and aquatic systems. Despite promising results under controlled conditions, challenges in standardizing biodegradation assessments and discrepancies between laboratory and real-world scenarios complicate evaluations of the temporal fate and the effects of BMPs. This work underscores the need for long-term studies and improved modeling approaches to accurately predict BMP behavior and mitigate their ecological impact. Poly(hydroxyalkanoates) are a class of fully biodegradable polymers that do not leave behind persistent microplastics. Biodegradable plastics should be prioritized over non-degradable, traditional polymers, as they can replace them in a large fraction of applications, yet with a significantly reduced footprint and without leaving behind persistent micro- and nanoplastics. They can also be recycled. Full article

Bio-based compostable starch aerogels have significant potential as a sustainable alternative to traditional polymer aerogels across various applications. However, they suffer from very significant shrinkage, shown in published work as 40–50% using existing processes. We hypothesized that the shrinkage is largely caused by pore collapse through the solvent exchange process, during which the water used to fabricate the starch matrix is replaced with ethanol. To mitigate this issue, this work introduces two strategies: (1) implementing a deep-freezing protocol (DFP) prior to the solvent exchange, followed by pure ethanol solvent exchanges instead of water/ethanol mixtures, and (2) incorporating chitin as a structural additive. As a baseline, we fabricated potato starch aerogels (PSAs) using conventional processes of mixing, heating, and retrogradation. By applying a DFP before pure ethanol exchanges, shrinkage was reduced from 44% to 10% in pure PSA samples. Furthermore, the addition of chitin reduced shrinkage to 8% in potato starch-chitin aerogels. Porosity, density, surface area, pore size distribution, thermal decomposition temperature, thermal conductivities, and scanning electron microscopy images demonstrate a correlation between reduced shrinkage and desired thermal material properties. Full article

Peptides are substances with numerous applications in chemistry, biology, medicine, and agriculture. Systematization of knowledge related to peptides may well have not only scientific research but also economic consequences. This study examines the antioxidant activity of peptides and the ACE-inhibitory capacity of peptides. Peptides are considered here containing three or four amino acids. Nevertheless, instead of considering peptides as traditional molecules, an attempt is made here to systematize the corresponding endpoints as mathematical functions of lists of amino acids, rather than considering the corresponding atoms and covalent bonds. New techniques that may be useful in theory and in practice for the development of quantitative structure–property/activity relationships (QSPRs/QSARs) related to certain types of biological activity of peptides are proposed and discussed. Full article

The results of this study, which involved treating cotton fabrics with three fluorescent hyperbranched polymers modified with 1,8-naphthalamide (P1), acridine (P2), and dansyl (P3) groups, could have applications in the development of antimicrobial textiles with self-disinfecting ability. The polymers, dissolved in DMF/water solution, were deposited on the cotton fabric using the exhaustion method. The fabrics were thoroughly analyzed by reflection spectra, CIEL*a*b* coordinates, and color difference (∆E). The release of the polymers from the cotton surface was studied in a phosphate buffer with pH = 7.4 and an acetate buffer with pH = 4.5 at 37 °C for 10 h. It is shown that at pH = 7.4, the release of the three polymers occurs slowly (about 4–5%). In contrast, in an acidic medium, due to protonation of the tertiary amino group of 1,8-naphthalimide, P1 passes significantly more readily into the aqueous solution (35%). The possibility of singlet oxygen (¹O₂) generation by the polymers and the cotton fabrics treated with them under sunlight irradiation was followed using an iodometric method. The microbiological activity was investigated against Gram-positive Bacillus cereus and Gram-negative Pseudomonas aeruginosa as model bacterial strains in the dark and after irradiation with sunlight. The antimicrobial activity of the polymers increased after light irradiation, as ¹O₂ attacks and destroys the bacterial cell membrane. Scanning electron microscopy showed that a stable bacterial biofilm had formed on the untreated cotton surface, but treatment with hyperbranched polymers prevented its formation. However, many bacteria were still observed on the fiber surface when the microbial test was performed in the dark, whereas only a few single bacteria were noticed after the illumination. A virucidal effect against respiratory viruses HRSV-2 and AAdV-5 was observed only after irradiation with sunlight. Full article

Advancements in material science have made biopolymers a reliable solution in treating diseases for which there were no effective treatments. Intrauterine adhesions (IUAs) are the second leading cause of secondary infertility among women of reproductive age. Despite their negative impacts, the available data reveal that there is currently no effective treatment. This work serves to provide an overview of the progress in the biomedical application of biopolymers focusing on the clinical management of IUAs. Hysteroscopic adhesiolysis remains the standard treatment for IUAs, even though it is linked to recurrence and suboptimal reproductive outcomes. Efforts to improve IUAs treatment by combining hysteroscopy with adjuvants like physical barriers have not resulted in better outcomes. Biopolymers like hyaluronic acid (HA) represent a groundbreaking shift in regenerative medicine and have been used as anti-adhesives in the treatment of IUAs. This is attributed to their excellent biocompatibility, cell adhesiveness, biodegradability, low toxicity, and cell growth promotion ability. This study examines naturally occurring biopolymers, underscoring their biomedical applications, and limitations such as poor mechanical properties, rapid degradation, limited residence time, and bioavailability. Drawing from existing evidence and authors’ standpoints, innovative approaches harnessing the power of biopolymer engineering are suggested as future directions to overcome ongoing limitations. Full article

The immiscibility of thermoplastic starch (TPS) and polybutylene succinate (PBS) complicates the thermal processing of these materials. This study provides the first comparative assessment of two compatibilizers with differing reaction mechanisms, Joncryl^® ADR 4468 and epoxidized linseed oil (ELO), for the optimization of biobased TPS/PBS blends. A total of 13 batches, varying in compatibilizer and blend composition, were processed via hot melt extrusion and injection molding to produce pellets. Blends were analyzed using tensile and impact testing, differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), rheology, and scanning electron microscopy (SEM). The findings suggest that both compatibilizers can improve the compatibility of these blends, as evidenced by higher glass transition temperatures (T_g) compared to the reference batch (100-0-N/A). Joncryl^® ADR 4468 batches exhibit superior tensile strength and Young’s moduli, while ELO batches demonstrate greater elongation at break. The enhanced processability observed in Joncryl^® ADR 4468 is attributed to the increased polymer chain entanglement and molecular weight, whereas ELO facilitates greater chain mobility due to its plasticizing effect. These differences arise from the distinct mechanisms of action: Joncryl^® ADR 4468 promotes chain extension and crosslinking, whereas ELO mainly enhances flexibility through plasticization. Overall, this study provides a comparative assessment of these compatibilizers in TPS/PBS blends, laying the groundwork for future investigations into optimizing compatibilizer concentration and blend composition. Full article

Metabolism, the network of biochemical reactions that powers life, arose under conditions radically different from those on Earth today. Investigating its origins reveals how initially simple chemical processes gradually integrated nucleic acid and then protein catalysts, becoming progressively more complex and regulated until they evolved into the enzyme-rich systems observed in modern organisms. Here, we integrate multiple perspectives on the origin of metabolism, focusing primarily on an evolutionary trajectory from an RNA-based world, where ribozymes, metal ions, coenzymes, small peptides, and other small organic molecules worked in concert, to enzyme-driven metabolic networks. We also address the longstanding debates on whether these early metabolic pathways were largely autotrophic or heterotrophic, and consider so-called “pre-metabolisms” (non-enzymatic networks) as an alternative conceptual framework. We discuss key examples such as the Wood–Ljungdahl (W–L) pathway and the reverse tricarboxylic acid (TCA) cycle, both posited to function under early Earth conditions. Finally, we examine how the environment (e.g., minerals, clays, hydrothermal vents) shaped early metabolism, describe unresolved questions about the Last Common Ancestor’s catalytic repertoire and propose future directions that link geochemical insights with molecular biology and synthetic approaches. Full article

The adhesion of printing inks to printing substrates is a complex process influenced by both the physical and chemical properties of the printing substrate and of the printing ink. Synthetic paper, being a polymer with no absorption capability, limits the interaction between the ink and substrate, leading to lower adhesion values. On synthetic paper, the thicker polymer resin layer covering the microcapsules results in a more stable ink film and lighter print coloration. In contrast, UV-curable ink applied to bulky and recycled papers, which have porous structures, exhibits more dynamic interactions. The polymer resin in the ink penetrates the paper’s pores, forming a stronger bond with the paper fibers and improving adhesion quality. Surface roughness also plays a significant role in ink adhesion. Rough surfaces increase contact between ink and paper, enhancing mechanical adhesion by allowing the ink to “lock” into the surface’s irregularities. The surface energy (SFE) at the interphase between paper and ink is also a key factor. Low SFE promotes better wetting and ink absorption, improving adhesion. Ink penetration into the printing substrate is crucial for achieving high-quality adhesion. Full article

Biopolymers are revolutionizing the materials landscape, driven by a growing demand for sustainable alternatives to traditional petroleum-based materials. Sourced from biological origins, these polymers are not only environment friendly but also present exciting solutions in healthcare, packaging, biosensors, high performance, and durable materials as alternatives to crude oil-based products. Recently, biopolymers derived from plants, such as lignin and cellulose, alongside those produced by bacteria, like polyhydroxyalkanoates (PHAs), have captured the spotlight, drawing significant interest for their industrial and eco-friendly applications. The growing interest in biopolymers stems from their potential as sustainable, renewable materials across diverse applications. This review provides an in-depth analysis of the current advancements in plant-based and bacterial biopolymers, covering aspects of bioproduction, downstream processing, and their integration into high-performance next-generation materials. Additionally, we delve into the technical challenges of cost-effectiveness, processing, and scalability, which are critical barriers to widespread adoption. By highlighting these issues, this review aims to equip researchers in the bio-based domain with a comprehensive understanding of how plant-based and bacterial biopolymers can serve as viable alternatives to petroleum-derived materials. Ultimately, we envision a transformative shift from a linear, fossil fuel-based economy to a circular, bio-based economy, fostering more sustainable and environmentally conscious material solutions using novel biopolymers aligning with the framework of the United Nations Sustainable Development Goals (SDGs), including clean water and sanitation (SDG 6), industry, innovation, and infrastructure (SDG 9), affordable and clean energy (SDG 7), sustainable cities and communities (SDG 11), responsible production and consumption (SDG 12), and climate action (SDG 13). Full article

The ageing of cellulose paper-based transformer insulation is a critical factor influencing the reliability and lifespan of power transformers, as insulating paper is not easily replaced or repaired. Therefore, this review explores the degradation mechanisms of insulating paper, emphasising the roles of dissolved gases, chemical markers, and macromolecular characterisation in assessing paper deterioration. Likewise, the impact of moisture and thermal stress on the breakdown of cellulose fibres are discussed, especially acid hydrolysis, which serves as the main degradation mechanism in cellulose insulating paper. Advanced diagnostic techniques for insulation condition monitoring, such as molecular simulations, glass transition temperature analysis, and DP estimation models, are highlighted. Furthermore, special attention is given to natural esters as alternative insulating liquids, demonstrating their ability to slow cellulose ageing through moisture absorption, hydrogen bonding stabilisation, and transesterification reactions. This paper also evaluates key chemical markers, including 2FAL and methanol, for estimating paper degradation. A comprehensive understanding of these mechanisms and diagnostic approaches can enhance predictive maintenance strategies and improve transformer longevity. Full article

As the global plastic pollution crisis intensifies, the development of sustainable food packaging materials has become a priority. Starch-based films present a viable, biodegradable alternative to petroleum-derived plastics but face challenges such as poor moisture resistance and mechanical fragility. This review comprehensively examines state-of-the-art advancements in starch-based packaging, including polymer modifications, bio-nanocomposite incorporation, and innovative processing techniques that enhance functionality. Furthermore, the role of advanced analytical tools in elucidating the structure–performance relationships of starch films is highlighted. In particular, we provide an in-depth exploration of advanced characterization techniques, not only to assess starch-based food packaging but also to monitor starch retrogradation, including Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), nuclear magnetic resonance (NMR), and iodine binding (Blue Value). We also explore cutting-edge developments in active and intelligent packaging, where starch films are functionalized with bioactive compounds for antimicrobial protection and freshness monitoring. While substantial progress has been made, critical challenges remain in upscaling these technologies for industrial production. This review provides a roadmap for future research and the industrial adoption of starch-derived packaging solutions. Full article

Unexpected mutations in SARS-CoV-2 produce unique variations. While numerous vaccines and antiviral medications are available for SARS-CoV-2, their use in controlling and preventing COVID-19 is restricted in some areas and countries due to accessibility and cost issues. This study investigated polysaccharides produced from two brown seaweed (Padina boergesenii and Sargassum euryphyllum) for their capacity to inhibit SARS-CoV-2. The seaweed polysaccharides were characterized and identified using ultraviolet and visible (UV/VIS) and Fourier transform infrared attenuated total reflectance (FTIR-ATR) spectra. The polysaccharides inhibited SARS-CoV-2 propagation with inhibitory concentration 50% (IC₅₀) values ranging from 24.2 to 29.3 µg/mL and cytotoxicity concentration 50% (CC₅₀) values for Vero-E6 cells ranging from 587.7 to 396.4 µg/mL for P. boergesenii and S. euryphyllum, respectively. P. boergesenii polysaccharide had a more substantial antiviral potential than S. euryphyllum against SARS-CoV-2 and appeared more promising. At a concentration of 575 µL/mL of P. boergesenii polysaccharide, the virucidal mechanism was found to be the most effective, followed by viral adsorption and replication, with viral inhibition percentages of 68.6% ± 0.8, 57.1% ± 1.4, and 37.2 ± 3, respectively, compared to remdesivir as an antiviral drug. Thus, we concluded that brown seaweed alginate polysaccharides efficiently inhibit SARS-CoV-2 from spreading by preventing viral entry. Finally, P. boergesenii polysaccharide looked promising as a potential therapeutic candidate for the treatment of COVID-19. Full article

Many modern technologies rely on materials that harm the environment. Glass manufacturing, for instance, is both expensive and environmentally damaging. In response, scientists have developed a technique to replace glass with transparent wood, an innovative, versatile, and sustainable alternative. Wood naturally retains heat, is durable, and remains cost-effective, making it promising substitute for glass and plastic in window production. This innovation highlights the urgent need for eco-friendly technologies to replace or improve existing materials. This work explores cork as a sustainable alternative for producing transparent materials, potentially replacing transparent wood. Unlike wood, cork can be harvested from the same tree for up to 300 years. The process followed a method like transparent wood production, involving delignification, bleaching, and forced polymer impregnation. The choice of bleaching agent significantly impacted results—samples treated with sodium hypochlorite solution appeared whiter but became extremely fragile, whereas hydrogen peroxide preserved mechanical properties better. The resin-to-hardener ratio was crucial, with higher resin content improving polymer infiltration and transparency. While fully transparent cork was not achieved, the resulting translucent material lays the groundwork for future research in this field. Full article

Poly(lactic acid) (PLA) is derived from sugar-based materials. While it is a leading sustainable biopolymer, PLA has been integrated with other agricultural coproducts (e.g., lignin, protein, and starch) to reduce its cost and enhance its modulus and biodegradability. Cottonseed oil and meal are the byproducts of the cotton fiber industry. In this work, four biocomposites were formulated with PLA, cottonseed oil, washed cottonseed meal, and plasticizing reagent glycerol with different formulation ratios. The thermal degradation behaviors were examined via thermogravimetric (TG) analysis under air and nitrogen conditions with the neat PLA sample as a control. The thermal decomposition characteristic values were impacted by both the biocomposite formulation and the heating rates of 1, 2, 5, and 10 °C min⁻¹. Results from two kinetic modeling methods that were examined indicated that the activation energy was relatively steady for the neat PLA in the whole degradation process. Generally, the low activation energy values of biocomposites other than PLA under nitrogen conditions implied that these cottonseed byproduct constituents promote the thermal decomposition of these biocomposites. However, the presence of oxygen would confound the thermal decomposition of the biocomposites, as shown by variable activation energy curves with higher values under air conditions. TG-FTIR analysis revealed that the major gaseous compounds were carbonyl, carbon dioxide, carbon monoxide, methane, and water, which were derived from the thermal decomposition of the biocomposites. Full article

Antimicrobial resistance (AMR) is a major global health problem, exacerbated by the excessive and inappropriate use of antibiotics in human medicine, animal care and agriculture. Therefore, new strategies and compounds are needed to overcome this issue. In this view, it may be appropriate to reconsider existing biomaterials to alleviate antibiotic overuse. Chitin, a naturally abundant amino mucopolysaccharide, is a poly-β-1, 4-N-acetylglucosamine (GlcNAc). It is a white, hard, inelastic, nitrogenous polysaccharide and the major source of surface pollution in coastal areas. Chitosan derives from the partial N-deacetylation of chitin and originates from the shells of crustaceans and the fungi cell walls. It is a nontoxic natural antimicrobial polymer approved by GRAS (Generally Recognized as Safe by the United States Food and Drug Administration). Chitin and chitosan, as non-toxic biopolymers, are useful compounds for wastewater treatment to remove pollutants, such as pharmaceuticals, heavy metals and dyes. The described features make these biopolymers intriguing compounds to be investigated for their application as antibacterials. Full article

Recently, many industries are adopting closed-loop recycling models to recover and reuse production scrap in order to reduce waste, conserve resources, and minimize environmental impact. In this scenario, this paper aims to simulate such a model using biodegradable pipe scrap, with the objective of studying how the concentration of recycled biodegradable pipe scrap affects mechanical and rheological properties and to evaluate the effectiveness of this approach. Firstly, irrigation pipes were subjected to multiple extrusions to evaluate their thermal and mechanical stability under repeated processing. Subsequently, blends of virgin polymer and biodegradable irrigation pipe scraps (monopolymer blends) were prepared following an industrial approach. All systems were fully characterized through mechanical and rheological tests. The results obtained showed that multiple extrusions had a significant impact on the mechanical and rheological properties of the pipe, while the presence of reprocessed pipe in the blend only minimally affected the characteristics of the virgin biopolymer, demonstrating the effectiveness of this approach. Full article