Search Results (3,584)

This study explored the dual chemical modification of starch isolated from red lentils (Lens culinaris) to develop a biodegradable polymer with enhanced functionality for multifaceted applications. Native starch was isolated via combined salt–alkali treatment and sequentially modified through epichlorohydrin-mediated crosslinking, followed by cationization using glycidyl trimethylammonium chloride (GTAC). Utilizing a Quality by Design (QbD) strategy through Response Surface Methodology (RSM), the cationization endured fine-tuning to reach an optimal degree of substitution (DS = 0.572) under foremost conditions (GTAC: 2.1 mol, NaOH: 0.09 mol, reaction time: 18 h). Structural and functional characterization using FTIR, XRD, TGA, SEM, and zeta potential analysis confirmed the successful modification, indicating enhanced thermal stability, a transition to a more amorphous structure, and a moderately positive surface charge (+7.24 mV). The dual modified cationic lentil starch (CLS) demonstrated effective flocculation of kaolin suspensions, achieving a transmittance of up to 94%. Additionally, CLS showed significantly improved emulsion stability, maintaining over 70% stability after 24 h, compared to native starch, which dropped below 30%. These results emphasize the promising potential of CLS as an eco-friendly and high-performance alternative to synthetic polymers for water treatment and stabilization of emulsion-based formulations. Full article

Hydrogels have emerged as promising functional materials for improving water management and nutrient delivery in agriculture, particularly under conditions of increasing water scarcity and declining soil fertility. However, most commercially available superabsorbent hydrogels are based on petroleum-derived polymers, raising concerns regarding their persistence in soils, potential microplastic formation and long-term environmental impact. In response, significant research efforts are being directed toward the development of biodegradable hydrogels derived from renewable biopolymers. This review provides a critical overview of recent advances in hydrogel systems designed for agricultural applications, with a particular focus on biopolymer-based materials. First, the current landscape of hydrogel technologies used as soil conditioners and controlled-release systems for agrochemicals is contextualized, highlighting the limitations of conventional synthetic hydrogels. Subsequently, the main classes of natural polymers explored for hydrogel fabrication, including polysaccharides (e.g., chitosan, alginate, cellulose and starch) and proteins (e.g., gelatin, keratin and soy protein), are analyzed in terms of raw material sources, gelation mechanisms and structure–property relationships. Their performance in key agricultural functions, such as water retention, controlled nutrient release, soil conditioning and enhancement of plant growth, is also discussed. Finally, the review identifies major challenges that currently hinder large-scale implementation, including mechanical stability, degradation behavior in complex soil environments, nutrient release control and economic scalability. By integrating recent progress and outlining emerging research directions, this work aims to support the rational design of next-generation biodegradable hydrogels capable of contributing to sustainable agriculture and circular bioeconomy strategies. Full article

Polyethylene terephthalate (PET) is a synthetic polymer that is widely used in the production of textiles, packaging materials, and beverage bottles. However, its high durability and resistance to abiotic degradation result in serious environmental and health problems. PETase is an enzyme that can depolymerize PET into value-added products, thereby providing an environmentally friendly strategy for PET recycling. PETaseSM14 from a marine sponge, Streptomyces sp. SM14, has a high salt tolerance and thermal stability, thus suggesting its potential for PET degradation applications. However, the substrate recognition mechanism of PETase remains unclear because the catalytic residue is buried within residues that form the substrate-binding cleft. To elucidate the molecular mechanism of PETaseSM14, all-atom molecular dynamics simulations were performed at 300, 320, and 340 K. The results revealed that the overall α/β fold remained stable at all temperatures, whereas temperature-dependent local fluctuations and conformational changes were observed in the substrate-binding cleft and N-terminal region. At 300 and 320 K, positional shifts and conformational changes in Tyr88 exposed the catalytic Ser156 to the solvent, thereby forming a potential substrate-binding cleft. In contrast, at 340 K, which is higher than the melting temperature of PETaseSM14, disruption of the charge-relay system of the catalytic triad occurs through conformational changes in His234. Substantial temperature-dependent conformational and positional changes in the N-terminal region of PETaseSM14 were observed at 320 and 340 K. These results provide mechanistic insight into the temperature-dependent active-site rearrangements and offer rational engineering strategies to enhance the efficiency of PETase for PET biodegradation. Full article

It is essential to develop a practical technology for the separation and capture of carbon dioxide (CO₂) due to the gradually increased concentration of CO₂ in the atmosphere, which has driven the rise in global temperature. Membrane separation is regarded as a promising technology for the capture of CO₂. However, most membranes employ non-biodegradable petroleum-based polymers. In this study, biodegradable and renewable membranes of cellulose acetate (CA) doped with polyethylene glycol (PEG) and polyethylene glycol diacrylate (PEGDA) were fabricated by solution casting and used for the separation of CO₂/O₂. The results indicated that the membrane doped with PEGDA exhibited higher permeability of CO₂ and selectivity of CO₂/O₂ compared to those doped with PEG, while improving the tensile strain and structural uniformity of membranes. The membrane with a thickness of 25 μm at a PEGDA dosage of 10 wt% achieved optimal gas permeability, selectivity, and mechanical toughness, showing CO₂ permeability of 4.59 Barrer and CO₂/O₂ selectivity of 5.68. The structure of the interpenetrating polymer network was responsible for the excellent properties of the membrane doped with PEGDA due to the formation of more mid- and micro-sized pores that increase the diffusion pathways of CO₂. Full article

Biodegradable nanocomposite materials possessing self-healing behavior are emerging as an attractive option of being used in advanced mechatronic systems. The current study is focused on a thorough examination of the micromechanical properties of graphene–reinforced polylactic acid (PLA)/polycaprolactone (PCL) composite samples, followed by estimation of their self-healing behavior upon heating. Polymer blend–based nanocomposite materials were prepared using the green and reliable in terms of good nanofiller dispersion melt extrusion method. 3D printed nanocomposite specimens with impeccable flatness were subjected to fine microscratch testing by applying a constant force experimental mode. The surface resistance of the three-component polymer materials against the lateral movement of the stylus fulfilling the scratch and the impact of the dual-phase PLA/PCL ratio on the nanocomposite mechanical performance were estimated by calculation of the coefficient of friction (COF = F_x/F_z). COF values in the range of 0.8–1.4 indicated excellent nanocomposite resilience against scratch. Creating a heterogeneous polymer system that combines phase-separated soft and hard domains with close melt and glass transition temperatures, respectively, may facilitate the physical flow of macromolecular chains into voids or free volume areas. This aspect can be critical in the achievement of thermally–induced self-healing properties of the composite material. Scanning electron microscopy (SEM) imaging of the microscratches, made before and after Joule heating of the polymer samples, revealed a significant degree of surface recovery and a sensible reduction in the width of the adjusted scratch grooves. Full article

Agro-industrial waste-derived materials are promising candidates for short-cycle packaging applications. Here, we report a proof-of-concept for biodegradable biocomposites formulated with cassava residue (CR), sugarcane bagasse (SCB), and bacterial cellulose (BC) produced by symbiotic fermentation (SCOBY). This approach addresses the mechanical limitations typically associated with cassava starch-based matrices by introducing natural reinforcements to improve structural integrity and cohesion. A set of formulations with varying CR/BC/SCB ratios was processed and assessed through tensile and flexural testing, elongation at break, thermal analysis, and water-related behavior (sorption, absorption, and contact angle). Among the evaluated blends, formulation F1 (80% CR, 5% BC, 15% SCB) delivered the best overall balance between performance and moldability, achieving a tensile strength of 11.97 MPa and showing good dimensional stability. Biodegradability was confirmed by composting, reaching 72.74% mass loss after 84 days. Overall, BC incorporation improved matrix cohesion and enabled control of mechanical integrity and wettability in the blends, as highlighted for F1 (tensile strength 11.97 MPa; peak force 560.32 N; contact angle 65°; water absorption rate, WAR, 58.68%; sorption time 5.4 s). Given the abundance of sugarcane and cassava residues in Northeast Brazil, this low-complexity route leverages locally available feedstocks to add value to regional waste streams and support the partial replacement of synthetic polymers. Full article

Alginate–chitosan composites are widely used bio-based materials due to their biocompatibility, biodegradability, and relatively simple processing methods. By combining the complementary properties of alginate and chitosan, these systems offer adjustable mechanical characteristics suitable for applications such as tissue engineering, wound healing, drug delivery, and sustainable packaging. However, although many studies report improved mechanical properties, the link between structural design and mechanical behavior is often discussed within specific applications rather than examined in a broader context. This review focuses on how polymer ratio, charge balance, crosslinking strategy, reinforcement approach, and processing conditions influence the mechanical properties of alginate–chitosan composites. Instead of considering these factors separately, the available studies are discussed in terms of how the internal structure of the composite affects stiffness, strength, deformability, and stability. This review brings together findings from various fields to highlight shared structure–mechanical relationships and to provide guidance for designing alginate–chitosan composites with specific mechanical properties. Full article

The growing interest in bio-based and biodegradable polymer composites reinforced with agricultural waste reflects global efforts to reduce dependence on fossil resources and improve the sustainability of materials. However, biocomposites are not necessarily more sustainable, and their environmental performance requires careful life cycle assessment (LCA). This review critically analyses recent LCA studies of biodegradable biocomposites reinforced with agricultural waste, focusing on methodological choices, data quality, results and limitations. A systematic literature review was conducted using the Scopus database, focusing on studies from the last five years. Selected studies were examined using a structure consistent with ISO 14040, with defined data extraction categories and key questions. The analysis shows that although biocomposites often demonstrate advantages in terms of climate change and fossil resource depletion compared to traditional materials, the results vary significantly depending on the definition of the functional unit, geographical context, processing pathways, and data assumptions. Limitations include reliance on laboratory data, uncertainties, incomplete system boundaries, inconsistent allocation methods, and limited end-of-life (EoL) modelling. Overall, the review highlights the need for improved data quality, performance-based functional units, geographically representative inventories, and more standardised LCA practices to ensure meaningful comparisons and support the sustainable development of biocomposites. Full article

Sustainable alternatives to synthetic polymer-based sanitary napkins are essential to reduce the environmental impact and health concerns. This study presents a method for using water hyacinth (Eichhornia crassipes), an invasive aquatic weed, as biomass to produce biodegradable absorbent material for sanitary pads. Water hyacinth fibers were treated with an alkaline solution and incorporated into the absorbent core. Morphological, chemical, structural, functional, microbiological, and biodegradability evaluations were then conducted systematically. Scanning electron microscopy showed that non-cellulosic components were successfully removed, producing a rougher surface topology and enhanced fiber interactions. Fourier-transform infrared spectroscopy confirmed structural changes in cellulose after treatment. Additionally, X-ray diffraction showed that the crystallinity index increased from 53.21% in untreated fibers to 62.56% in treated fibers, indicating improved order and stability. The developed absorbent sanitary pad showed rapid fluid uptake, absorbing 10 mL within three seconds while maintaining a skin-compatible neutral pH of 6.87, as specified in Indian Standard IS 5405:1980. Microbial contamination remained low, with a total bacterial count of 360 CFU/g, no yeast or mold at ≤1 CFU/g, and no presence of Staphylococcus aureus. Soil burial tests showed 70% biodegradability at 40 days and approximately 95% at 60 days, indicating high biodegradability. These findings demonstrate the potential of water hyacinth as an inexpensive and environmentally friendly material for manufacturing hygienic sanitary pads, highlighting the sustainability benefits of valorizing invasive biomass and reducing reliance on synthetic polymers. Full article

pH-responsive indicator films for intelligent food packaging applications are based on the embedding of a natural or synthetic dye in a polymeric substrate, preferably biobased and biodegradable. Although natural colorants like anthocyanins were extensively investigated in this respect, nature-inspired synthetic flavylium compounds could represent an alternative based on their higher stability. In this work, five novel synthetic 4′-aminoflavylium derivatives with different substitution patterns in the benzopyrylium core (compounds 1–5) were synthesized and characterized. Polyvinyl alcohol (PVA), as well as chitosan–PVA and chitosan–starch blends, were used to prepare pH-responsive indicator films having inserted each of the synthesized flavylium dyes or a natural onion peel extract. The PVA films with compounds 1 and 3, and the PVA–chitosan film with compound 1, exhibited antioxidant activity, highlighting their potential for active packaging applications. All indicator films showed pH responsiveness in the range of 2 to 12 and were subsequently tested in contact with the packaging atmosphere or in direct contact with pork and fish meat, at different temperatures (4 °C, 20 °C, and 40 °C) for 24 h to assess their colorimetric response to progressive spoilage. Although the differences were small, the films with the 7-hydroxy-4′-aminoflavylium derivative exhibited the earliest and most intense color change during storage of meat, starting from direct contact at 4 °C for 24 h, being able to identify the initial stages of meat spoilage, while the performance of the dihydroxy-substituted derivative was attenuated by incorporation in polymer matrices. This behavior was comparable to that of onion peel extract, but the synthetic flavylium derivative was more stable. The results can provide new opportunities for intelligent food packaging applications using biopolymer indicator films with 4′-aminoflavylium derivatives. Full article

In this study, multilayer films were produced using a co-extrusion process involving two complementary bioplastics: Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and Mater-Bi^®. PHBV is recognized, among biodegradable polymers, for its excellent oxygen barrier properties, but is also known for being brittle, non-sealable, and difficult to process. Conversely, Mater-Bi^® has good processability, low stiffness, and high ductility, but exhibits poor barrier properties. The research investigated the barrier, mechanical, sealing, and optical properties of the films to evaluate how variations in layer structure and processing parameters influenced their overall performance. The results showed that the addition of the PHBV layer, both as a neat polymer and as a blend with Mater-Bi^®, significantly reduced oxygen and water vapor permeability. Additionally, Mater-Bi^® was found to be essential for providing the elasticity and sealability required for the multilayer films. The study also demonstrated that layer thickness plays a critical role in property tailoring. Full article

The 4D printing of thermo-responsive shape-memory multicomponent polymer composites, which possess the ability to change shape by exposure to heat, has attracted much attention in recent years because of their scientific and technological significance. In the present study, we investigate shape memory performance of a polylactic acid-polycaprolactone-graphene nanocomposite activated directly by increasing the environmental temperature and indirectly, by Joule heating. The incorporation of graphene within the shape-memory biopolymer blend allowed formation of a programmable conduction path, whose electric properties are intimately coupled to thermo-mechanical processes. Advanced rheological, thermal, and thermo-mechanical properties were evaluated and related to the structure of nanocomposite. The electrically and thermally stimulated shape memory and self-healing behavior of the nanocomposite based on polycaprolactone/poly(lactic) acid blend reinforced with graphene nanoplatelets (PCL/PLA/GNP) were investigated. The shape memory tests revealed a good reversibility of 76% between the temporary and permanent states of the samples bent to 180 degrees and a high healing efficiency of 96% if stimulated by Joule heating. The highly electroactive nanocomposite demonstrated a great potential for 4D-printing of objects with complex structures, shapes, and electrically-stimulated shape-memory and self-healing functions. The nanocomposite is biodegradable, recyclable, and reusable, which may reduce the carbon footprint of the rapidly developing additive technology. Full article

The environmental persistence of post-consumer plastics remains a critical challenge due to their chemical stability, the presence of additives, and prior environmental weathering. This study evaluates the partial biodegradation and chemical transformation of post-consumer low-density polyethylene (LDPE) and expanded polystyrene (EPS) by Tenebrio molitor larvae under uncontrolled environmental conditions. Four diets were tested, including LDPE+S and EPS+S (polymers supplemented with wheat bran), to assess the influence of a co-substrate on larval performance and polymer transformation. Fourier-transform infrared spectroscopy (FTIR) revealed the emergence of oxygen-containing functional groups (–OH and C=O) in the frass, which were absent or negligible in pristine materials, indicating oxidative modification of the polymer matrix. Gel permeation chromatography (GPC) revealed pronounced reductions in number-average molecular weight (Mn) and increased polydispersity for EPS-derived fractions, consistent with heterogeneous chain scission and partial depolymerization. For LDPE, GPC evidenced the formation of THF-soluble, low-molecular-weight polymer-derived fragments, indicating fragmentation despite the inability to quantify pristine LDPE due to its insolubility in the mobile phase. Gas chromatography–mass spectrometry (GC–MS) identified aromatic hydrocarbons, phthalate esters, organosiloxanes, and fatty acid derivatives, reflecting both degradation intermediates and migrated additives from post-consumer plastics. Together, these results provide integrated evidence that Tenebrio molitor can induce chemical transformation of post-consumer LDPE and EPS under non-controlled environmental conditions, offering mechanistic insight into a biologically mediated degradation pathway that is directly relevant to realistic plastic waste scenarios. Full article

Magnetic resonance imaging (MRI) is one of the most powerful non-invasive methods for cancer diagnostics. To enhance image contrast and, therefore, diagnostic accuracy, contrast agents (CAs) are widely used in clinics. For decades, the clinical standard has been metal-based CAs, primarily gadolinium- and manganese-based chelates, or iron oxide nanoparticles. However, metal-based CAs possess sub-effects, toxicity, and associated adverse health effects, such as nephrogenic systemic fibrosis. As an alternative, metal-free organic radical CAs (ORCAs), based on nitroxides, have been developed. ORCAs are widely used as primary ¹H-MRI agents and offer many advantages, including high biocompatibility, biodegradability, and easy functionalization. Attachment of nitroxides to natural or synthetic polymers enables the development of constructs with prolonged systemic circulation time and tumor-targeted delivery. Furthermore, MR-signal amplification can be achieved through physical hyperpolarization techniques, such as dynamic nuclear polarization (DNP) and Overhauser-enhanced MRI (OMRI), in which nitroxide radicals serve as hyperpolarizing agents, yielding signal enhancements. This review summarizes low-molecular-weight nitroxides, polymeric, and biomacromolecular platforms for ¹H-MRI, focusing on physicochemical properties, preclinical evidence in tumor imaging, and current limitations. One section highlights the use of nitroxides as hyperpolarizing agents for tumor metabolism analysis or OMRI. The review addresses ongoing challenges and outlines future perspectives for the clinical translation of ORCAs in cancer diagnostics. Full article

This study presents the effect of gamma rays of up to 2000 kGy on the chemical structure and the physical properties of a poly(butylene adipate-co-terephthalate) (PBAT) with 48% mol of terephthalic units. PBAT is a polymer with properties similar to polyethylene (PE) but it is biodegradable and not toxic to the environment, and it can be prepared with a renewable content of up to 68.6% weight, with uses in biomedicine and packaging. Previous studies found in the literature have been conducted using low doses and the results were contradictory. The results for gel content and crosslinking efficiency were in agreement with the results found in the literature. Molecular weight decreased and widened with the increase in dose. Proton NMR analysis was used for the first time in PBAT to determine the changes in chemical species, the formation of new chemical species, and the bonds more susceptible to be broken by gamma rays. Both thermal and mechanical properties were explained by the scission of the chains in the amorphous phase and at the boundaries of the crystallites. The thermal parameters most affected by irradiation were the crystallization temperature and temperature of melting after cooling from the melt. Stress and strain at break suffered a continuous decrease with dose until PBAT became fragile at high dose. Full article