Novel Biodegradable Poly (Lactic Acid)/Wood Leachate Composites: Investigation of Antibacterial, Mechanical, Morphological, and Thermal Properties

Sage seed gum-gelatin composite films and electrospun zein fibers: A sustainable bilayer system enriched with pomegranate flower extract

In the present research, bilayer films containing different thicknesses of electrospun zein layers with varying concentrations of pomegranate flower extract (0, 20, 40, 60, and 80 g·m-2) were successfully developed. Morphological analysis revealed that increasing the thickness of the electrospun layer resulted in a denser and more uniform structure in the bilayer films. Given zein's water-insoluble nature, increasing the electrospun layer's thickness from 0 to 80 novel led to an increase in the contact angle from 73.2° to 90.1°, resulting in a hydrophobic film surface. This also resulted in reductions of 44 %, 34.5 %, and 35.9 % in water solubility, moisture content, and swelling ratio, respectively. Additionally, the FTIR results confirmed the formation and enhancement of interaction, such as hydrogen bonds, between the components of the bilayer films with the increase in electrospun layer thickness. These interactions significantly enhanced the thermal stability, degree of crystallization, tensile strength (up to a 42 % increase), elastic modulus (up to a 27 % increase), and oxygen and water vapor barrier properties of the bilayer films. The antioxidant activity, measured by DPPH radical scavenging, increased from 5.24 % to 78.15 % as the thickness of the electrospun layer increased. The electrospun layer's thickness significantly influenced the antimicrobial activity, resulting in the highest inhibition zones against E. coli and S. aureus, which measured 15.6 mm and 17.3 mm in diameter, respectively. Release studies in different simulants revealed that the highest release rate of pomegranate flower extract from the bilayer films occurred in alcohol and fatty simulants. In contrast, the lowest release rate was observed in aqueous and acidic simulants. This innovative approach presents a promising alternative to conventional petroleum-based packaging.

Advanced biopolymer films for sustainable applications: Integrating Fe₃O₄ and ZnO nanoparticles into pea protein isolate-alginate matrices

This study aimed to develop an innovative approach for electrically and magnetically responsive smart films based on pea protein isolate (PPI) and alginate. The effects of varying concentrations of Fe₃O₄ (5 % and 10 %) and ZnO (3 % and 6 %) nanoparticles on the physical, mechanical, structural, barrier, thermal, chemical, antimicrobial, and electrical properties of the films were evaluated. Results revealed that increasing the nanoparticle concentration enhanced the thickness and mechanical strength of the films by 29.2 % and 13.8 %, respectively. Interactions between nanoparticles and the biopolymer structure were confirmed through FTIR analysis, which also demonstrated improved thermal stability and uniform structure. The addition of nanoparticles induced significant changes in the surface morphology, forming a relatively compact and homogeneous matrix. These modifications reduced water vapor and oxygen permeability by 41.8 % and 39.9 %, respectively. Furthermore, increased nanoparticle concentrations elevated the opacity and darkness of the composite films while decreasing their whiteness index. Elemental analysis using energy-dispersive X-ray Spectroscopy (EDX) showed a relatively uniform distribution of iron and zinc, indicating effective nanoparticle dispersion. Due to the inorganic nature of the nanoparticles, their increased concentration led to reductions in water solubility, moisture content, and swelling ratio by 42.7 %, 48.1 %, and 43.9 %, respectively. The electrical analysis showed that the electrical conductivity of the composite films, initially at 0.009 S·m-1 in the absence of nanoparticles, increased to 0.138 S·m-1 with the inclusion of 10 % Fe₃O₄ and 6 % ZnO. These findings highlight the potential of nanoparticle-reinforced biopolymer films for applications in active packaging and intelligent polymer systems.

Multifunctional bilayer films based on pea protein isolate and alginate with Fe₃O₄ nanoparticles

The objective of the present study was to develop multifunctional bilayer films for sustainable applications using a pea protein isolate (PPI)-alginate (AL) base layer and an electrospun PPI-polyvinyl alcohol (PVA) fiber layer containing Fe₃O₄ nanoparticles. This research systematically investigated the effects of varying Fe₃O₄ nanoparticle concentrations (0 %, 3 %, 6 %, 9 %, and 12 %) on the properties of bilayer films, as well as the surface tension and electrical conductivity of the electrospinning solution. Strong interactions between Fe₃O₄ nanoparticles and the electrospun PPI-PVA fibers were confirmed by FTIR and XRD analyses, resulting in enhanced thermal stability, mechanical properties, and barrier performance with increasing nanoparticle concentration. For instance, tensile strength, water vapor permeability (g·m-1·Pa-1·s-1), and oxygen permeability (g·m-2·s-1) of the nanoparticle-free film were 36.7 MPa, 1.04 × 10-9, and 0.68 × 10-3, respectively, which changed to 39.4 MPa, 0.56 × 10-9, and 0.41 × 10-3, respectively, at 12 % nanoparticle concentration. FESEM analysis confirmed the formation of smooth nanofibers at low concentrations, while higher concentrations resulted in irregular fiber morphology and bead formation. The increase in electrical conductivity and reduction in surface tension of the electrospinning solution with higher Fe₃O₄ nanoparticle concentrations led to an increase in the diameter of the electrospun PPI-PVA fibers. Enhanced functional properties, including antioxidant and antimicrobial activities, were observed with increasing concentrations of Fe₃O₄ nanoparticles. Biodegradability studies confirmed the environmental compatibility of the developed bilayer films, highlighting their potential use in sustainable and eco-friendly applications.

Multiphase Biopolymers Enriched with Suberin Extraction Waste: Impact on Properties and Sustainable Development

This manuscript explores the development of sustainable biopolymer composites using suberin extraction waste, specifically suberinic acid residues (SAR), as a 10% (w/w) reinforcing additive in polylactide (PLA) and thermoplastic starch-polylactide blends (M30). The materials were subjected to a detailed analysis using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA) to assess their thermal, mechanical, and structural properties. The study confirmed the amorphous nature of the biopolymers and highlighted how SAR significantly influences their degradation behavior and thermal stability. M30 exhibited a multi-step degradation process with an initial decomposition temperature (T5%) of 207.2 °C, while PLA showed a higher thermal resistance with decomposition starting at 263.1 °C. Mechanical performance was assessed through storage modulus (E') measurements, showing reductions with increasing temperature for both materials. The research provides insights into the potential application of SAR-enriched biopolymers in sustainable material development, aligning with circular economy principles. These findings not only suggest that SAR incorporation could enhance the mechanical and thermal properties of biopolymers, but also confirm the effectiveness of the research in reassurance of the audience.

A review on hazards and treatment methods of released antibiotics in hospitals wastewater during the COVID-19 pandemic

Drugs and related goods are widely used in order to promote public health and the quality of life. One of the most serious environmental challenges affecting public health is the ongoing presence of antibiotics in the effluents generated by pharmaceutical industries and hospitals. Antibiotics cannot be entirely removed from wastewater using the traditional wastewater treatment methods. Unmetabolized antibiotics generated by humans can be found in urban and livestock effluent. The antibiotic present in effluent contributes to issues with resistance to antibiotics and the creation of superbugs. Over the recent 2 years, the coronavirus disease 2019 pandemic has substantially boosted hospital waste volume. In this situation, a detailed literature review was conducted to highlight the harmful effects of untreated hospital waste and outline the best approaches to manage it. Approximately 50 to 70% of the emerging contaminants prevalent in the hospital wastewater can be removed using traditional treatment strategies. This paper emphasizes the numerous treatment approaches for effectively eliminating emerging contaminants and antibiotics from hospital wastewater and provides an overview of global hospital wastewater legislation and guidelines on hospital wastewater administration. Around 90% of ECs might be eliminated by biological or physical treatment techniques when used in conjunction with modern oxidation techniques. According to this research, hybrid methods are the best approach for removing antibiotics and ECs from hospital wastewater. The document outlines the many features of effective hospital waste management and might be helpful during and after the coronavirus disease 2019 outbreak, when waste creation on all hospitals throughout the globe has considerably increased.

Eco-Friendly Wood Composites: Design, Characterization and Applications

The ongoing transition from a linear to a circular, low-carbon bioeconomy is crucial for reducing the consumption of global natural resources, minimizing waste generation, reducing carbon emissions, and creating more sustainable growth and jobs, the prerequisites necessary to achieve climate neutrality targets and stop biodiversity loss [...].

An Overview on Wood Waste Valorization as Biopolymers and Biocomposites: Definition, Classification, Production, Properties and Applications

Bio-based polymers, obtained from natural biomass, are nowadays considered good candidates for the replacement of traditional fossil-derived plastics. The need for substituting traditional synthetic plastics is mainly driven by many concerns about their detrimental effects on the environment and human health. The most innovative way to produce bioplastics involves the use of raw materials derived from wastes. Raw materials are of vital importance for human and animal health and due to their economic and environmental benefits. Among these, wood waste is gaining popularity as an innovative raw material for biopolymer manufacturing. On the other hand, the use of wastes as a source to produce biopolymers and biocomposites is still under development and the processing methods are currently being studied in order to reach a high reproducibility and thus increase the yield of production. This study therefore aimed to cover the current developments in the classification, manufacturing, performances and fields of application of bio-based polymers, especially focusing on wood waste sources. The work was carried out using both a descriptive and an analytical methodology: first, a description of the state of art as it exists at present was reported, then the available information was analyzed to make a critical evaluation of the results. A second way to employ wood scraps involves their use as bio-reinforcements for composites; therefore, the increase in the mechanical response obtained by the addition of wood waste in different bio-based matrices was explored in this work. Results showed an increase in Young's modulus up to 9 GPa for wood-reinforced PLA and up to 6 GPa for wood-reinforced PHA.

Thermal and Sliding Wear Properties of Wood Waste-Filled Poly(Lactic Acid) Biocomposites

In our study, the effects of wood waste content (0, 2.5, 5, 7.5, and 10 wt.%) on thermal and dry sliding wear properties of poly(lactic acid) (PLA) biocomposites were investigated. The wear of developed composites was examined under dry contact conditions at different operating parameters, such as sliding velocity (1 m/s, 2 m/s, and 3 m/s) and normal load (10 N, 20 N, and 30 N) at a fixed sliding distance of 2000 m. Thermogravimetric analysis demonstrated that the inclusion of wood waste decreased the thermal stability of PLA biocomposites. The experimental results indicate that wear of biocomposites increased with a rise in load and sliding velocity. There was a 26-38% reduction in wear compared with pure PLA when 2.5 wt.% wood waste was added to composites. The Taguchi method with L₂₅ orthogonal array was used to analyze the sliding wear behavior of the developed biocomposites. The results indicate that the wood waste content with 46.82% contribution emerged as the most crucial parameter affecting the wear of PLA biocomposites. The worn surfaces of the biocomposites were examined by scanning electron microscopy to study possible wear mechanisms and correlate them with the obtained wear results.

3D Printing Application in Wood Furniture Components Assembling

Additive manufacturing (AM) is used in many fields and is a method used to replace wood components or wood-jointed furniture components in the furniture industry. Replacing wood joints by 3D printed connectors would be an advantage, considering the fact that during the process of assembling furniture, the execution technology of the joints is difficult, time-consuming, and labor-intensive. Advanced technology of AM applied in furniture manufacturing helps the designers to create new concepts of product design, with no limits of shape, number of joints, color, or size. The diversity of 3D printers and AM technologies provides the selection of materials in relation with the applicability of the 3D printed object. In this respect, the objective of the present research is to design a 3D printed connector to be used for jointing three chair components, namely the leg and two stretchers made from larch (Larix decidua Mill.) wood, and to use reinforced polylactic acid (PLA) fiberglass (20 wt. %) filament for 3D printing this connector using AM with fused filament fabrication (FFF) technology. The design of the connector, the possibility of using this type of material, and the deposition method of filament were investigated in this research. For this purpose, several evaluation methods were applied: microscopic investigation with 50×, 100×, and 200× magnifications, both of the filament and of the 3D printed connector; mechanical testing of corner joint formed with the help of connector between chair leg and the two stretchers; and a microscopic investigation of the connectors’ defects that occurred after applying the compression and tensile loads on the diagonal direction of the L-type joint. The microscopic investigation of the composite filament revealed the agglomerations of glass fibers into the core matrix and areas where the distribution of the reinforcements was poor. The heterogeneous structure of the filament and the defects highlighted in the 3D printed connectors by the microscopic investigation contributed to the mechanical behavior of L-type connecting joints. The bending moments resulting from compression and tensile tests of the 3D printed connectors were compared to the results recorded after testing, under the same conditions, the normal mortise–tenon joint used to assemble the abovementioned chair components. The larch wood strength influenced the mechanical results and the conclusions of the microscopic investigations, as well as the analysis of the broken connectors after testing recommended the change of connector design and filament deposition direction.