Search Results (112)

Thermoplastic starch (TPS) blended with biodegradable polyesters such as polyhydroxybutyrate (PHB), polylactic acid (PLA), polybutylene succinate (PBS), and polycaprolactone (PCL) represents a promising route toward sustainable alternatives to petroleum-based plastics. TPS offers advantages related to abundance, low cost, and biodegradability, while polyesters provide improved mechanical strength, thermal stability, and barrier performance. However, the intrinsic incompatibility between hydrophilic TPS and hydrophobic polyesters typically leads to immiscible systems with poor interfacial adhesion and limited performance. This review critically examines recent advances in the development of TPS/polyester blends, with emphasis on compatibilization strategies based on chemical modification, natural and synthetic compatibilizers, bio-based additives, and reinforcing agents. Particular attention is given to the role of organic acids, essential oils, phenolic compounds, nanofillers, and natural reinforcements in controlling morphology, crystallinity, interfacial interactions, and thermal–mechanical behavior. In addition, the contribution of bioactive additives to antimicrobial and antioxidant functionality is discussed as an emerging multifunctional feature of some TPS/polyester systems. Finally, current limitations related to long-term stability, scalability, and life cycle assessment are highlighted, identifying key challenges and future research directions for the development of advanced biodegradable materials with tailored properties. Full article

This study investigates the adsorption of paracetamol from aqueous solutions using natural clinoptilolite and its modified forms. The raw zeolite (p-CLI) was converted into its protonic (H-CLI) and organo-modified (o-CLI) counterparts through ammonium exchange and calcination, and treatment with hexadecyltrimethylammonium bromide (HDTMA-Br), respectively. The materials were characterized by XRD, FT-IR, and SEM analyses. XRD confirmed that the clinoptilolite crystalline framework was preserved after both modifications, while FT-IR and SEM revealed partial removal of exchangeable cations in H-CLI and the formation of an HDTMA-derived organic layer on the external surface of o-CLI. Adsorption experiments were carried out under batch conditions at initial paracetamol concentrations of 0.5–10 mg/L, and equilibrium paracetamol concentrations were determined using differential pulse voltammetry (DPV). The raw clinoptilolite exhibited negligible adsorption capacity (<0.10 mg/g) due to its hydrophilic surface and microporous framework, which limit interaction with neutral organic molecules. Conversion to the protonic form slightly enhanced the adsorption performance (~0.15 mg/g), while HDTMA modification resulted in a modest additional increase (~0.25 mg/g), attributed to the formation of hydrophobic and organophilic surface sites. Overall, the results indicate that surface functionalization can improve the affinity of clinoptilolite toward weakly polar pharmaceuticals; however, the adsorption capacities remain limited. The novelty of this work lies in combining voltametric quantification with a direct comparison of proton-exchanged and surfactant-modified clinoptilolite to elucidate how specific structural and surface changes influence paracetamol uptake. Full article

This work examined the effects of four plasticizers, glycerol (GLY), potassium phosphate (PHOS), polyethylene glycol (PEG), and soy lecithin (SL), on the structural, surface, thermal, optical, and mechanical properties of polyhydroxybutyrate (PHB) films. FTIR spectra demonstrated that these plasticizers maintained the PHB molecular structure, while X-ray diffraction data proved that PHB crystallinity decreased upon adding SL, GLY, and PHOS. Under SEM, we discovered several defects in the plasticized samples, most of which were holes of distinct sizes and forms. The thermal analyses evaluated the impact of plasticization on PHB thermal processability, demonstrating that the material’s thermal stability improved, easing thermal processing due to the reduced melting peak temperatures (T_m) caused by all the additives assessed. While PEG, GLY, and PHOS reduced the hydrophilicity of the film, SL enhanced its affinity to water, as shown by the contact angle measurements. Reduced transparency resulted from adding 20% plasticizers with an increase of 345% in elongation at break and a decrease of 67% in elastic modulus compared to pristine PHB. Thus, SL proved to be the most promising of the four plasticizers used in terms of mechanical properties, crucial for PHB-based films for food packaging. Full article

Background: Enhancing bioavailability is the target of most pharmaceutical research; this can be achieved by modifying the physico-chemical characteristics of poorly water-soluble drugs intended for oral administration using different techniques. The preparation of liquitablets by blister molding technique provides an opportunity to increase the bioavailability of the drug using an optimal combination of release-facilitating additives. Lornoxicam is an effective non-steroidal anti-inflammatory drug with low water solubility. This study aimed to formulate a novel lornoxicam-containing liquitablets. The effect of different drying techniques on the physico-chemical properties and in vitro dissolution of lornoxicam was investigated. The physical parameters of the tablets were also studied. Methods: The additives applied in the formulation included Tween^® 80, Polyvinylpyrrolidone (PVP K90), Avicel^® PH-102, and sodium bicarbonate. Vacuum-drying and freeze-drying were employed to produce liquitablets. The influence of various drying methods on crystallinity and intra- and interparticle phenomena was investigated. In Vitro dissolution tests were performed at pH 1.2, and a comparison was made between our products and commercial tablets using the pairwise similarity factor model (f2). Results: The liquitablets demonstrated high hydrophilicity and a lower crystallinity of the drug. Freeze-dried liquitablet showed improved dissolution compared to that of the pure drug or the vacuum-dried product. A similarity was observed between our freeze-dried product and the marketed fast-release tablets. Conclusions: This research demonstrates that preparation of liquitablet in combination with freeze-drying has a significantly positive effect in improving the in vitro dissolution rate of lornoxicam. Full article

Most existing polymer plastics are nonreusable and also exhibit poor biocompatibility and a poor mechanical strength–tensile strain balance. Herein, using deep eutectic polymers, we prepare reusable hydrophilic supramolecular dry gel plastics with balanced stress–strain characteristics through the hydrogen bonding of poly(vinyl alcohol) (PVA) with betaine (Bta). As PVA exhibits crystalline stiffness and abundant hydrogen-bonding sites, it is employed as a network backbone in the proposed deep eutectic supramolecular polymers. In the prepared PVA/Bta dry gel plastics, PVA and Bta are dynamically and physically crosslinked through high-density hydrogen bonding, resulting in a yield strength of ~109 MPa and toughness of up to ~210.92 MJ m⁻³. In addition, these plastics can be recycled at least five times in an aqueous environment while maintaining a mechanical strength of 100 MPa. Furthermore, the proposed polymers exhibit high transparency (92%) in the visible spectrum. We expect these polymers to be used in synthesizing biodegradable dry gel plastics, as well as to lead to the development of recyclable deep eutectic PVA/Bta polymers with remarkable strength. Full article

The study examined composites composed of curauá fibers (10%) and a high-density bio-based polyethylene (HDBPE) matrix, emphasizing the effects of processing methods on their final properties. In addition, plant-derived oils were applied as compatibilizers to improve the interfacial adhesion between the hydrophilic fibers and the hydrophobic HDBPE, thereby supporting the process’s sustainability. The comparative analysis of HDBPE/curauá fiber/plant-based oil composites utilized distinct methodologies: compounding with an internal mixer, followed by thermopressing and mixture composition using a twin-screw extruder with subsequent injection molding. Castor oil (CO), canola oil (CA), or epoxidized soybean oil (OSE) were employed as compatibilizers (5%). All composites displayed high levels of crystallinity (up to 86%) compared to neat HDBPE (67%), likely due to interactions with curauá fibers and compatibilizers. The use of twin-screw extruder/injection molding produced composites with higher impact and flexural strength/modulus-assessed at 5%(approximately 222 J/m to 290 J/m; 22/700 MPa to 26/880 MPa, respectively), considerably exceeding those formed via internal mixer/thermopressing (approximately 110 J/m to 123 J/m; 14/600 MPa to 20/700 MPa). Micrographs of the composites indicated that the extruder separated the fiber bundles into smaller-diameter units, which may have facilitated the transfer of load from the matrix to the fibers, optimizing the composite’s mechanical performance. As a compatibilizer, CO enhanced both properties and, when combined with the twin-screw extruder/injection technique, emerged as the optimal choice for HDBPE/curauá fiber composites. Full article

This study concerns the effects of the addition of crystalline nanocellulose (CNC) and ionizing radiation on the properties of cornstarch–poly(vinyl alcohol) (PVA) films. Moreover, ESR spectroscopy and gas chromatography were used for a comparison of the reactivity of CNC and two micro-sized celluloses (microfibrinal (MFC) and microcrystalline (MCC)) under the influence of irradiation. This showed that the highest reactivity of CNC was related to the lowest sizes of the particles (observed by SEM). A series of starch/PVA/CNC films characterized by a starch/PVA ratio equal to 40:60 and a CNC addition in a range from 0.5 wt% to 10.0 wt% with 30 wt% of glycerol were prepared by solution casting. The films were irradiated in a gamma chamber (in a vacuum) or in an e-beam (in the air) using a dose of 25 kGy. The mechanical properties, contact angle to water, swelling and solubility in water, moisture absorption in a humid atmosphere, and the gel content of the films were determined. The functional properties of the films strongly depended on the addition of CNC. The films formed with 1.0 wt% of CNC had the best mechanical properties and the lowest surface and bulk hydrophilicity, which could be improved further after irradiation. The results can be related to the increased homogeneity and modified distribution of the nanoparticles in the films after irradiation (as shown by SEM). Degradation is a predominant process that occurs due to irradiation; however, the crosslinking processes also have some role. The protective effect of CNC against degradation was discovered by diffuse reflectance spectroscopy. Full article

As a porous crystalline material, covalent organic frameworks (COFs) have attracted significant attention due to their extraordinary features, such as an ordered pore structure and excellent stability. Synthesized through the aldehyde amine condensation reaction, TpPa-1 COFs (Triformylphloroglucinol-p-Phenylenediamine-1 COFs) were blended with cellulose acetate (CA) to form a casting solution. The TpPa-1 COF/CA ultrafiltration membrane was then prepared using the non-solvent-induced phase inversion (NIPS) method. The influence of TpPa-1 COFs content on the hydrophilicity, stability and filtration performance of the modified membrane was studied. Due to the hydrophilic groups in TpPa-1 COFs and the network structure formed by covalent bonds, the modified CA membranes exhibited higher hydrophilicity and lower protein adsorption compared with the pristine CA membrane. The porous crystalline structure of TpPa-1 COFs increased the water permeation path in the CA membrane, improving the permeability of the modified membrane while maintaining an outstanding bovine serum albumin (BSA) rejection. Furthermore, the addition of TpPa-1 COFs reduced protein adsorption on the CA membrane and overcame the trade-off between permeability and selectivity in CA membrane bioseparation applications. This approach provides a sustainable method for enhancing membrane performance while enhancing the application of membranes in protein purification. Full article

This research explores the synthesis of carboxymethyl cellulose (CMC) for the development of a cost-effective bioplastic film that can serve as a sustainable alternative to synthetic plastic. Replacing plastic packaging with CMC-based films offers a solution for mitigating environmental pollution, although the inherent hydrophilicity and low mechanical strength of CMC present significant challenges. To address these limitations, zinc oxide nanoparticles (ZnO NPs) were employed as a biocompatible and non-toxic reinforcement filler to improve CMC’s properties. A solution casting method which incorporated varying concentrations of ZnO NPs (0%, 5%, 10%, 15%, 20%, and 25%) into the CMC matrix allowed for the preparation of composite bioplastic films, the physicochemical properties of which were analyzed using scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. The results revealed that the ZnO NPs were well-integrated into the CMC matrix, thereby improving the film’s crystallinity, with a significant shift from amorphousness to the crystalline phase. The uniform dispersion of ZnO NPs and the development of hydrogen bonding between ZnO and the CMC matrix resulted in enhanced mechanical properties, with the film CZ₂₀ exhibiting the greatest tensile strength—15.12 ± 1.28 MPa. This film (CZ₂₀) was primarily discussed and compared with the control film in additional comparison graphs. Thermal stability, assessed via thermogravimetric analysis, improved with an increasing percentage of ZnO Nps, while a substantial decrease in water vapor permeability and oil permeability coefficients was observed. In addition, such water-related properties as water contact angle, moisture content, and moisture absorption were also markedly improved. Furthermore, biodegradability studies demonstrated that the films decomposed by 71.43% to 100% within 7 days under ambient conditions when buried in soil. Thus, CMC-based eco-friendly composite films have the clear potential to become viable replacements for conventional plastics in the packaging industry. Full article

The laser pyrolysis technique was used in the synthesis of magnetic iron oxide nanopowders in the presence of ethanol vapors as a sensitizer. This technique uses the energy from a continuous-wave CO₂ laser operating at a 9.25 μm wavelength, which is transferred to the reactive precursors via the excited ethanol molecules, inducing a rapid heating of the argon-entrained Fe(CO)₅ vapors in the presence of oxygen. For a parametric study, different samples were prepared by changing the percentages of sensitizer in the reactive mixture. Moreover, the raw samples were thermally treated at different temperatures and their morpho-structural and magnetic properties were investigated. The results indicated a high degree of crystallinity (mean ordered dimension) and enhanced magnetic properties when high percentages of ethanol vapors were employed. On the contrary, at low ethanol concentrations, due to a decrease in the reaction temperature, nanoparticles with a very low size were synthesized. The raw particles have a dimension in the range of 2.5 to 10 nm (XRD and TEM). Most of them exhibited superparamagnetic behavior at room temperature, with saturation magnetization values up to 60 emu/g. The crystalline phase detected in samples is mainly maghemite, with a decreased carbon presence (up to 8 at%). In addition to the expected Fe-OH on the particles surfaces, C (and O) bearing functional groups such as C-OH or C=O that act as a supplementary hydrophilic agent in water-based suspension were detected. Using the as-synthesized and thermally treated nanopowders, water suspensions without or with hydrophilic agents (CMCNa, L-Dopa, chitosan) were prepared by means of a horn ultrasonic homogenizer at 0.5 mg/mL concentrations. DLS analyzes revealed that some powder suspensions maintained stable agglomerates over time, with a mean size of 100 nm, pH values between 4.8 and 5.3, and zeta-potential values exceeding 40 mV. All tested agents greatly improved the stability of 250–450 °C thermally treated NPs, with L-Dopa and Chitosan inducing smaller hydrodynamic sizes. Full article

Carbon quantum dots (CQDs), a distinctive class of fluorescent carbon nanomaterials, exhibit considerable potential for widespread application across several industries due to their safety, environmental sustainability, excellent water solubility, and tunable yet stable fluorescence properties. Nevertheless, the mass field is limited, and the cost of production is higher for the majority of methods. This study examines a cost-effective approach for the hydrothermal synthesis of nitrogen-doped carbon quantum dots (N-CQDs) from wood using NH₃·H₂O as the nitrogen precursor, facilitated by H₂O₂ and ultraviolet light. The produced N-CQDs demonstrate superior crystallinity and solubility in water, with the average particle size of 5.02 nm. After 10 experiments under the same conditions, a significant and stable yield of 5.04 g (42 wt%) was finally obtained by hydrothermal synthesis. The N-CQDs solution exhibits green fluorescence when exposed to ultraviolet light, and its fluorescence performance is influenced by concentration and excitation wavelength. Furthermore, it explores their application in identifying Fe (III) in water. The surface of N-CQDs is abundant in hydrophilic hydroxyl groups, distinctive nitrogen-containing groups, and various oxygen-containing functional groups. Fe (III) can extinguish fluorescence in water. The ratio of fluorescence intensity before and after to the addition of Fe (III) solution to the N-CQDs solution (F₀/F) exhibits the effective linear correlation within the concentration range of 0.1 to 100 μmol/L. Within the concentration range of 100 to 1000 μmol/L, the increase in Fe (III) concentration results in substantial aggregation of Fe (III) and N-CQDs, along with a blue shift in the fluorescence wavelength. This discovery possesses significant potential for the synthesis and application of environmentally friendly, high-yield N-CQDs. Full article

Absorption of exudates is crucial for moist wound treatment, particularly in chronic wound care applications. However, controlling wound exudates with current gel-based wound dressings has challenges, such as the risk of bacterial infection during long-term transportation and use. In this study, a bacterial cellulose (BC)/polyvinyl alcohol (PVA) composite hydrogel (PBC) was prepared by a simple method using citric acid (CA) as the crosslinking agent. Fourier-transform infrared spectroscopy showed that the reaction between the carboxyl group of CA and the hydroxyl group of the BC-PVA hydrogel enhanced its hydrophilicity. Sol–gel analysis confirmed that an increase in the PVA content led to stronger crosslinking of the polymer network in the hydrogel. Wide-angle X-ray diffraction results showed that at low PVA concentrations, the tendency to connect with cellulose chains and crystallinity increased. In addition, the hydrogel dressing demonstrated excellent water absorption capacity; the swelling rate reached 3485.3% within one hour, and no cytotoxic effect was observed on the L929 fibroblast line in vitro. The designed hydrogel exhibited the ability to resist bacteria. Therefore, the new PBC biomaterial has certain potential for various applications, particularly as a highly absorbent dressing. Full article

In this work, the structure of silica thin films synthesized with three different SiO₂ precursors and obtained by the sol–gel method and dip coating technique was studied. Additionally, the influence of Ag addition on the obtained silica sols and then gel structure was investigated. Silica coatings show antireflective properties and high thermal resistance, as well as hydrophobic or hydrophilic properties. Three different silica precursors, TEOS (tetraethylorthosilicate), DDS (dimethyldietoxysilane) and Aerosil^TM, were selected for the synthesis. DDS added to silica sol act as a pore size modifier, while Ag atoms are known for their antibacterial activity. Coatings were deposited on two different substrates: steel and titanium, dried and annealed at 500 °C in air (steel substrate) and in argon (titanium substrate). For all synthesized films, IR (infrared) spectroscopic studies were performed together with GID and XRD (Grazing Incidence Diffraction, X-ray Diffraction) measurements. The topography and morphology of the surface were traced by SEM and AFM microscopic methods, providing information on the samples’ roughness, particle sizes and thickness of the particular layers. The wetting angle values were also measured. GID and XRD measurements pointed to the distinct contribution of an amorphous phase in the samples, allowing us to recognize the crystalline phases and calculate the silver crystallite sizes. The FTIR spectra gave information on the first coordination sphere of the studied samples. Full article

Crystalline diamond nanoparticles which are 3.6 nm in size adhering to thin-film silicon results in a hydrophilic silicon surface for uniform wetting by electrolytes and serves as a current spreader for the prevention of a local high-lithium-ion current density. The excellent physical integrity of an anode made of diamond on silicon and the long-life and high-capacity-retention cycling performance are thus achieved for lithium-ion batteries. A specific capacity of 1860 mAh/g(si) was retained after 200 cycles of discharge/charge at an areal current density of 0.2 mA/cm². This is compared to 1626 mAh/g(si) for a thin-film-silicon anode without the additive of diamond nanoparticles. Full article

The utilization of biopolymers incorporated with antimicrobial agents is extremely interesting in the development of environmentally friendly functional materials for food packaging and other applications. In this study, the effect of calcium oxide (CaO) on the morphological, mechanical, thermal, and hydrophilic properties as well as the antimicrobial activity of carboxymethyl chitosan (CMCH) bio-composite films was investigated. The CMCH was synthesized from shrimp chitosan through carboxymethylation, whereas the CaO was synthesized via a co-precipitation method with polyethylene glycol as a stabilizer. The CMCH-CaO bio-composite films were prepared by the addition of synthesized CaO into the synthesized CMCH using a facile solution casting method. As confirmed by XRD and SEM, the synthesized CaO has a cubic shape, with an average crystalline size of 25.84 nm. The synthesized CaO exhibited excellent antimicrobial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) (>99.9% R). The addition of CaO into CMCH improved the mechanical and hydrophobic properties of the CMCH-CaO films. However, it resulted in a slight decrease in thermal stability. Notably, the CMCH-CaO10% films exhibited exceptional antimicrobial activity against E. coli (98.8% R) and S. aureus (91.8% R). As a result, such bio-composite films can be applied as an active packaging material for fruit, vegetable, or meat products. Full article