Search Results (293)

This study aimed to evaluate how hydration temperature, rotational speed, and screw restriction influence the extraction efficiency, physicochemical characteristics, and monosaccharide composition of chia seed mucilage (CSM). Optimal extraction conditions (43.7 Hz, 100% screw restriction and 50 °C) yielded an extraction efficiency of 65.69% and a mucilage yield of 7.66%, producing a material with an average particle size of 15.28 μm, a ζ-potential of 9.7 mV, and weak-gel rheological behavior. Structural analyses confirmed the absence of insoluble fiber and revealed crystalline phases including MgO, Ca₅P₈, K₂S, K₄P₆, and CaCO₃, along with typical polysaccharide functional groups (–OH, –CH, C=O, COO⁻, C–O). Moderate hydration temperature combined with controlled mechanical conditions favored the release of mucilage enriched in xylose, glucose, and arabinose, which are characteristic of seed coat polysaccharides. In contrast, minimal mechanical action or excessive seed disruption shifted the monosaccharide profile toward cell wall structural carbohydrates, indicating reduced mucilage purity. Elevated hydration temperature (75 °C) enhanced the solubilization of uronic acids and arabinose, suggesting increased extraction of acidic polysaccharide fractions associated with the seed coat matrix. These findings demonstrate that extraction parameters strongly determine CSM composition, structural integrity, and functional attributes. The results provide a basis for tailoring chia-derived polysaccharides for applications in hydrocolloid systems, bio-based materials, and functional polymer formulations. Full article

Sulfonated aromatic polymers (SAPs) represent promising alternatives to perfluorinated ionomers for proton-exchange membrane fuel cells (PEMFCs), but their high hydrophilicity and limited chemical stability often require structural reinforcement and controlled cross-linking. In this study, composite membranes based on sulfonated poly(phenylsulfone) (SPPSU) and sulfonated poly(ethersulfone) (SPES) were fabricated with and without electrospun PPSU nanofiber mats and subsequently cross-linked through a solvent-induced sulfone-bridge formation at 180 °C. SPPSU/SPES blends (70/30, 50/50, 30/70) displayed good miscibility, while PPSU fibers improved dimensional stability and suppressed excessive swelling. Cross-linking strongly influenced membrane properties: intermediate treatment (20 h) enhanced mechanical strength and solvent resistance with limited loss of IEC, whereas extended treatment (30 h) produced highly stable, low-swelling networks. Despite lower IEC and water uptake, 30 h-treated membranes exhibited higher proton conductivity, attributed to reduced tortuosity and more continuous ionic pathways. Mechanical and hydration analyses identified SPPSU-50, SPPSU-70, and SPPSU-100 as the most balanced compositions. Proton mobility analysis revealed high membrane tortuosity, consistent with dense cross-linked structures reinforced by fibers. Overall, the combined use of SPPSU/SPES blending, PPSU nanofiber reinforcement, and sulfone-bridge cross-linking yields robust, water-insoluble membranes with improved electrochemical performance suitable for PEMFCs and other applications. 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

Recent findings demonstrate that concentrated sulfuric acid supports rich organic chemistry, including the stability of the canonical DNA bases adenine, thymine, guanine and cytosine. Yet, due to full protonation in concentrated sulfuric acid, these bases may not pair as effectively as they do in water. We are therefore motivated to study nucleic acid bases that pair via hydrophobic and van der Waals interactions instead of canonical hydrogen bonding. Here, we investigate the stability of 14 selected, commercially available alternative nucleobases in concentrated sulfuric acid to evaluate their potential for forming DNA-like polymers in this solvent. The reactivity of compounds 1–14 have not been previously investigated in concentrated sulfuric acid. We incubate the selected compounds in 98% and 81% w/w sulfuric acid and monitor their stability using ¹H and ¹³C NMR spectroscopy over 3 weeks at room temperature. In 98% w/w sulfuric acid, six bases—benzo[c][1,2,5]thiadiazole (1), 2,2′-bipyridine (2), 1,1′-biphenyl (3), 1-methoxy-3-methylbenzene (MMO2) (7) and 1-chloro-3-methoxybenzene (ClMO) (13), and 2,4-difluorotoluene (14)—remain soluble and stable with no detectable degradation. A few compounds show non-destructive reactivity, like sulfonation (compound 3) or H/D exchange (compounds 7, 13, 14). The other compounds react rapidly or are insoluble in 98% w/w sulfuric acid. In 81% w/w sulfuric acid, only compounds 1 and 2 remain stable and soluble, while other selected compounds are insoluble or unstable. Our findings identify a subset of alternative bases stable in concentrated sulfuric acid, advancing efforts towards the design of an example genetic-like polymer in this unusual solvent. Our work further highlights sulfuric acid’s potential for supporting complex organic chemistry, with implications for astrobiology, planetary science of Venus and synthetic biology. Full article

Up to now, most hydrogel-related studies have been devoted to the preparation of drug-containing macromolecular gels via the introduction of polymer matrices, together with the clarification of their assembly mechanisms and biomedical applications. In contrast, studies concerning the design of small-molecule gel systems remain relatively limited. As gel research progresses, drug small-molecule hydrogels have attracted growing interest for formulation development. This study investigated whether designing a small-molecule hydrogel could serve as an effective solubilization approach for sulindac (SUL)—a nonsteroidal anti-inflammatory drug clinically restricted by its poor aqueous solubility. Then, a SUL small-molecule hydrogel was prepared by straightforward mixing of SUL with biologically safe meglumine (MEG) in a minimal volume of deionized water, which exhibited a characteristic three-dimensional network structure and favorable viscoelastic properties. The characterization and simulation results indicated that the hydrogel formation was contingent upon the SUL-MEG miscibility, dissolution-aggregation equilibrium and intermolecular self-assembly. Consequently, the resulting SUL-MEG hydrogel exhibited 546 times higher solubility compared to the pure SUL. Meanwhile, the SUL-MEG hydrogel demonstrated superior release kinetics and supersaturation capacity, characterized by rapid attainment of peak concentrations and sustained supersaturated release. These enhanced performances were attributed to the high-energy state of the hydrogel itself and the molecular complexation between SUL and MEG. In conclusion, this study presents a feasible formulation strategy for overcoming the poor water solubility of insoluble drugs through the development of small-molecule hydrogel formulations. Full article

The development of biocompatible and mechanically flexible skeletal scaffolds is a significant challenge in modern regenerative medicine. In this study, we developed composite scaffolds based on biodegradable chitosan polymer and hydroxyapatite particles. We have shown for the first time that treatment with sodium hydroxide solution, which is often used to convert chitosan scaffolds into an insoluble form, can cause alkali sorption by hydroxyapatite particles. This has been demonstrated by our experiments. It has also been shown that the alkaline treatment of composite scaffolds increases the pH of the surrounding culture medium, reducing the viability of mesenchymal stromal cells by 60–70%. As an alternative to the processing of composite scaffolds using chitosan and hydroxyapatite, we propose heat treatment. This method allows us to produce stable scaffolds without affecting cell viability. Heat treatment promotes the formation of bonds between free amino groups in chitosan and phosphate groups in hydroxyapatite, as well as increasing the elasticity of the composite matrices in humid conditions. Full article

Lupin (Lupinus spp.), a legume known for its high protein content, holds great promise as a sustainable protein source to meet future global demands. Despite its nutritional benefits, including substantial dietary fibre and bioactive compounds, lupin remains underutilised in human diets due to several techno-functional and sensory limitations. This review delves into the techno-functional limitations of lupin, which include poor foaming capacity, low water and oil absorption, inadequate emulsification properties, and poor solubility. Lupin’s techno-functional limits are tied to the compact, heat-stable nature of its conglutin storage proteins and high insoluble fibre content. While research has been conducted on fermenting other legumes such as soybeans, chickpeas, peas, and lentils with Exopolysaccharide (EPS) producing bacteria, its application to lupin remains largely unexplored. Crucially, this work is one of the first reviews to exclusively link lupin’s unique protein and fibre structure with the specific polymer chemistry of bacterial EPS as a targeted modification strategy. Current research findings suggest that EPS-producing Lactic Acid Bacteria (LAB) fermentation can significantly improve the techno-functional properties of legumes, indicating strong potential for similar benefits with lupin. The analysis highlights various studies demonstrating the ability of EPS-producing LAB to improve water retention, emulsification, and overall palatability of legume-based products. Furthermore, it emphasises the need for continued research in the realm of fermentation with EPS-producing bacteria to enhance the utilisation of lupin in food applications. By addressing these challenges, fermented lupin could become a more appealing and nutritious option, contributing significantly to global food security and nutrition. Full article

The identification and quantification of chitinolytic activity in microorganisms is critical for advancing biological control strategies against arthropod pests and fungal pathogens. However, current laboratory methods designed for fast detection of chitinolytic microorganisms are often time-consuming, produce low-quality results and lack sensitivity. Here, we report the development of a novel fluorogenic culture medium incorporating a chemically modified chitinase substrate, N-fluoresceyl poly-D-glucosamine, which allows for a highly sensitive chitinase assay, enabling both qualitative and quantitative fluorescent detection of chitinase activity in situ. This substrate is synthesized through covalent conjugation of poly-D-glucosamine with fluorescein isothiocyanate under alkaline conditions, resulting in an insoluble polymer that becomes fluorescent upon enzymatic hydrolysis by chitinases. When supplemented with culture media, the modified fluorogenic substrate serves as the sole carbon source, selectively supporting the growth of chitinolytic microorganisms. Enzymatic activity is visualized under longwave UV light and can be quantitatively measured via spectrophotometric (493 nm) or fluorometric (530 nm) methods. Validation using characterized entomopathogenic chitinolytic strains of the fungi Aspergillus flavus, Beauveria bassiana, and Metarhizium anisopliae demonstrated a detection sensitivity that was at least three orders of magnitude greater than that of conventional methods. In contrast, the non-chitinolytic fungi Penicillium notatum and Fusarium venenatum presented no detectable fluorescent signals. This fluorogenic medium provides a rapid, cost-effective, and highly sensitive tool for screening chitinolytic microorganisms with potential applications in agriculture, veterinary parasitology, and environmental microbiology. Full article

Pultrusion is a manufacturing process used to produce fiber-reinforced polymer composites with excellent mechanical, thermal, and chemical properties. The resulting materials are lightweight, durable, and corrosion-resistant, making them valuable in aerospace, automotive, construction, and energy sectors. However, conventional thermoset composites remain difficult to recycle due to their infusible and insoluble cross-linked structure. This review explores integrating vitrimer technology a novel class of recyclable thermosets with dynamic covalent adaptive networks into the pultrusion process. As only limited studies have directly reported vitrimer pultrusion to date, this review provides a forward-looking perspective, highlighting fundamental principles, challenges, and opportunities that can guide future development of recyclable high-performance composites. Vitrimers combine the mechanical strength (tensile strength and modulus) of thermosets with the reprocessability and reshaping of thermoplastics through dynamic bond exchange mechanisms. These polymers offer high-temperature reprocessability, self-healing, and closed-loop recyclability, where recycling efficiency can be evaluated by the recovery yield retention of mechanical properties and reuse cycles meeting the demand for sustainable manufacturing. Key aspects discussed include resin formulation, fiber impregnation, curing cycles, and die design for vitrimer systems. The temperature-dependent bond exchange reactions present challenges in achieving optimal curing and strong fiber–matrix adhesion. Recent studies indicate that vitrimer-based composites can maintain structural integrity while enabling recycling and repair, with mechanical performance such as flexural and tensile strength comparable to conventional composites. Incorporating vitrimer materials into pultrusion could enable high-performance, lightweight products for a circular economy. The remaining challenges include optimizing curing kinetics, improving interfacial adhesion, and scaling production for widespread industrial adoption. Full article

The retrogradation of starch strongly influences the texture and stability of starchy foods. This study applied low-field nuclear magnetic resonance (LF NMR) to examine the effect of buckwheat hull (BH) fiber and green barley (GB) on water dynamics in normal (NPS) and waxy (WPS) potato starch gels. Relaxation times (T₁, T₂) and mean correlation times (τ_c) were monitored during 15 days of storage to evaluate changes in water mobility and starch–polymer interactions. Results showed that WPS, with its high amylopectin content, retrograded earlier than NPS. The addition of BH inhibited conformational changes associated with water binding in WPS gels, indicating that insoluble fiber entrapped water within the amylopectin network. Conversely, GB promoted higher τ_c values in WPS, reflecting enhanced ordering and reduced water mobility, while its impact on NPS was minor. In NPS systems, BH decreased τ_c, suggesting disruption of amylose-driven structural reorganization. These findings demonstrate that BH and GB exert opposite effects on starch retrogradation and highlight their potential as functional additives for tailoring texture and stability in starch-based food systems. Full article

This study aimed to evaluate the physical properties and biodegradability of sulfur-vulcanized polyhydroxyalkanoates (PHAs) with unsaturated side chains. As a vulcanizable PHA, poly(3-hydroxybutyrate-co-3-hydroxy-5-hexenoate) [P(3HB-co-3H5HE)] was biosynthesized with a 3H5HE fraction of 3–47 mol% using recombinant Escherichia coli and subsequently vulcanized with varying sulfur contents (2–20 per hundred resin, phr) in the presence of zinc oxide, stearic acid, and 2-mercaptobenzothiazole as curing agents. The vulcanized PHA copolymers were insoluble in chloroform, indicating the formation of a cross-linked network. Raman spectroscopy revealed the functional loss of the double bonds in the polymers. After the vulcanization with 5 phr sulfur, the tensile strength and elongation at break of P(3HB-co-47 mol% 3H5HE) increased from 0.6 MPa to 6.3 MPa and from 430% to 813%, respectively. This sample exhibited low tensile set (8%) after 200% elongation, indicating rubber-like properties. Although biodegradability decreased with increasing crosslink density, vulcanized P(3HB-co-3H5HE) exhibited a greater degradation potential than vulcanized rubber but was lower than that of non-vulcanized P(3HB-co-3H5HE). These findings demonstrate that sulfur vulcanization can enhance the resilience of unsaturated PHAs, making them suitable for elastomeric and environmental applications. Full article

This study reports the synthesis of high cis-1,4 polybutadiene with a narrow molecular weight distribution (Đ < 2.0) by coordinative chain transfer polymerization (CCTP) using a homogeneous ternary NdV₃/diisobutyl aluminum hydride (DIBAH)/dimethyldichlorosilane (Me₂SiCl₂) Ziegler–Natta catalyst system. The polymerization parameters, notably the monomer-to-initiator ratio ([M]/[Nd]) and the halogen-to-initiator ratio ([Cl]/[Nd]), were systematically varied to define the CCTP operational window. It was found that CCTP conditions are achieved only at low [M]/[Nd] ratios (<2500) and intermediate [Cl]/[Nd] ratios between 1.0 and 2.0, facilitating the production of polymers with molecular weights below 32 kDa and narrow dispersity. Increasing these ratios beyond these thresholds potentially induces the formation of insoluble, hyper-halogenated catalytic species and increases medium viscosity, which significantly broadens the molecular weight distribution (Đ > 4.0) and impairs CCTP control. These findings challenge previous assumptions that higher halogen concentrations are necessary for CCTP, thereby providing important mechanistic insights for tuning active species and achieving improved polymer architecture. The work demonstrates a viable pathway to control polymer microstructure and molecular weight in neodymium-based CCTP, which is critical for design of high-performance elastomeric materials. Full article

The development of robust and efficient β-mannanases is key to advancing environmentally friendly industrial processes, such as guar gum fracturing fluid gel-breaking. Here, we report the identification and characterization of MG4, a novel thermotolerant and alkaliphilic β-mannanase mined from the Earth’s Microbiome database. The recombinant enzyme has a molecular weight of 63 kDa. MG4 displayed maximum activity at 65 °C and pH 9.0, and exhibited remarkable stability across a broad pH range (7.0–10.0). It retained over 80% of its activity after incubation at 50 °C for 1 h, and its activity was enhanced more than 40% by Mg²⁺ or Ca²⁺. Moreover, MG4 (20 mg/L) reduced the viscosity of guar gum fracturing fluid to <5 m·PaS within 30 min, outperforming ammonium persulfate (APS, 500 mg/L) which required 1 h, and produced 64.5% less insoluble residue. TEM imaging directly visualized the disruption of the guar gum polymer network by MG4, explaining its efficacy and suggesting reduced formation damage risk compared to chemical breakers. This work characterizes a highly promising biocatalyst whose thermostability, alkaliphily, efficient gel-breaking, low residue yield, and minimal formation damage potential position it as a superior, eco-friendly alternative for petroleum industry applications. Full article

This study concerns the evaluation of adhesive and wettability energetic signatures of a model orthodontic wire exposed to commercial mouthrinses. The surface wetting properties were evaluated from the contact angle hysteresis (CAH) approach applied to dynamic contact angle data derived from the original drop on a vertical filament method. Young, advancing, receding CA apart from adhesive film pressure, surface energy, work of adhesion, etc. were chosen as interfacial interaction indicators, allowing for the optimal concentration and placement of the key component(s) accumulation to be predicted for effective antibacterial activity to eliminate plaque formation on the prosthetic materials. Surfactant compounds when adsorb at interfaces confer rheological properties to the surfaces, leading to surface relaxation, which depends on the timescale of the deformation. The surface dilatational complex modulus E, with compression elasticity E_d and viscosity E_i parts, determined in the stress–relaxation Langmuir trough measurements, exhibited the viscoelastic surface film behavior with the relaxation times (0.41–3.13 s), pointing to the vertically segregated film structure as distinct, stratified layers with the most insoluble compound on the system top (as indicated with the 2D polymer film scaling theory exponent y = 12.9–15.5). Kinetic rheology parameters could affect the wettability, adhesion, and spreading characteristics of mouthrinse liquids. Full article

This study focuses on functionalized nonwoven fabrics, modified with complexes of poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) and divalent metal ions (M²⁺). A bioactive PDMAEMA with tertiary amines was synthesized and applied to nonwoven fabrics using a spray-coating method. Functionalization was achieved by in situ complexation on PDMAEMA-modified nonwovens with solutions of divalent metal salts. The aim of the study was to demonstrate that the proposed textiles can serve as biologically active materials, effectively inhibiting the growth of harmful bacteria. The modification process was designed to ensure that the amount of PDMAEMA was sufficient to cover the entire surface of the nonwoven fabric. The weight efficiency of the polymer application was approximately 1.4% and 2.0%. The presence of the polymer was confirmed through functional group analysis and electrokinetic property measurements. The PDMAEMA surface layer on the nonwoven fabrics was subsequently cross-linked by divalent metal ions (M²⁺), supplied from aqueous solutions of the corresponding salts, thereby converting the modifier into an insoluble form. Morphological changes in the functionalized nonwoven fabrics demonstrated the effect of the complexes on surface topography. Energy-dispersive X-ray microanalysis confirmed the presence of metal ions on the functionalized nonwoven fabrics. The modified polylactide (PLA) nonwoven fabrics exhibited antibacterial properties against Escherichia coli. Full article