Biodegradable mulch films are essential for reducing plastic pollution in agriculture; however, current production methods often rely on complex and costly chemical processes. This study presents an innovative, ecofriendly approach to developing fully biodegradable mulch films using untreated vegetable stalks and sodium alginate through a simple blending method. By eliminating the need for pretreatment, this process significantly reduces energy consumption and maximizes agricultural waste utilization. The optimized film formulation (30 % vegetable stalk, 3 % solution, 40 % glycerin) demonstrated excellent mechanical and barrier properties, including tensile strength (6.8 MPa), elongation at break (29 %), water vapor permeability (1.88 x 10-12 g & sdot;cm-1 & sdot;Pa-1 & sdot;s-1), and UV-blocking efficiency (98.5 %), and thermal insulation and moisture retention properties. Rheological analysis showed that the addition of vegetable stalks impacted the film-forming solution's properties, enhancing processing and application performance. Additionally, the films facilitated seed germination and maintained functionality on the surface of moist soil, while rapidly degrading when buried in moist soil. Life Cycle Assessment confirmed that the biodegradable films significantly reduce environmental impacts, supporting their potential for widespread adoption in sustainable agricultural practices. This study provides a scalable and cost-effective strategy for converting agricultural residues into high-performance biodegradable films, addressing the need for sustainable solutions in agriculture and environmental protection.
Magnaporthe oryzae causes a fungal disease that poses a serious risk to global food security. Nanoagrochemicals are perceived as sustainable, economical, and environmentally friendly alternatives to traditional pesticides. Plant immune activators can be applied as the active ingredients of nanopesticides to control diseases in agriculture, but their use is limited and corresponding research is lacking. In this study, a nanodelivery system (PBZ@CaCO3@SG) for the on-demand release of a plant immune activator (probenazole; PBZ) was prepared using nano-CaCO3 after coating with sodium alginate-gelatin (SG). In vitro, at 48 h, the release rate reached 97.9% and 88.4% at pH 4.5 and 6.0, respectively, which greatly exceeded that under neutral conditions (pH 7.4), with acid-responsive release characteristics. Moreover, it responded quickly to the acidic microenvironment generated during M. oryzae infestation and rationally released PBZ, effectively improving plant resistance to M. oryzae and minimizing disease. Notably, M. oryzae infection was markedly reduced, by 60.6%, after PBZ@CaCO3@SG treatment. Mechanistically, PBZ@CaCO3@SG enhanced both physical barrier formation and systemic acquired resistance in rice, enhancing resistance to M. oryzae. It also showed good biosafety for both microbial communities and earthworms in the soil. This comprehensive study revealed multiple mechanisms by which PBZ@CaCO3@SG interacts with plants and pathogens, inhibits damage, and maintains nontarget biosafety, emphasizing its great potential for plant disease management.
To assess the stabilizing effect of sodium alginate (SA) on cement soil subjected to dry-wet cycles, a comprehensive study was conducted involving UCS tests, dynamic triaxial tests, SEM analysis, and XRD analysis. The results showed that after 11 dry-wet cycles, the residual strength of the cement soil was 11.25 kPa with a 90.1% strength loss rate, while the SA-modified soil had a 72% loss rate and a residual strength of 432 kPa. Dynamic strain increased and dynamic elastic modulus decreased with higher dynamic stress, while higher loading frequencies reduced dynamic strain and increased dynamic elastic modulus. Increased cycle counts led to higher dynamic strain and lower dynamic elastic modulus. The damping ratio curves shifted downward with higher frequencies and moved rightward with more cycles. SEM and XRD analyses revealed that SA formed reticular cementitious materials that encapsulated soil particles and aggregated fines into larger particles. Sodium alginate significantly enhanced the soil's resistance to dry-wet cycles, providing valuable insights for coastal and soft soil subgrade engineering design.
This study aims to develop an eco-friendly active packaging film to preserve perishable food. The film was prepared using natural polymers like sodium alginate and gelatin. Further, Clove oil was added to these films to improve their antioxidant and antimicrobial properties. The films' transmission was low, i.e., similar to 18.79% in 315-400 nm, lower, i.e., 14.41% in the UV region of 200-400 nm, and lowest, i.e., 12.21% in 200-280 nm with a band gap of similar to 3.52 eV, showing the effectiveness of films in shielding UV light. The films were hydrophilic and showed a low water vapor transmission rate. The packaging films showed thermal stability and reduced swelling. Freeze-thaw and high-temperature annealing significantly improved the film's mechanical properties (Y = 10.39 MPa and sigma = 23.37 MPa). The Chorioallantoic Membrane (CAM) assay in the chick model showed the films' biocompatibility. After 28 days, the films were completely biodegradable in soil, providing a sustainable solution for food packaging. Active packaging film showed significant antibacterial properties against Gram-positive S. aureus (colony-forming unit (CFU) reduced from 92 +/- 4.2 to 3 +/- 0.2, i.e., 96.74 +/- 5.13% inhibition) and Gram-negative E. coli (colony-forming unit reduced from 106 +/- 6 to 95 +/- 4.11, i.e., 96.13 +/- 3.41%). These films showed significant antioxidant activity and effectively delayed the decay of bananas (Musa acuminata), making them a promising solution for food packaging with excellent UV blocking, antimicrobial, and antioxidant properties. [GRAPHICS] .
Super absorbent polymers (SAPs) used in sanitary napkin are not required for water absorption capacity as high as in baby diapers and adult incontinence pads. Sanitary napkins must absorb menses, which is delivered at a significantly lower rate and overall daily amount than urines. Thus, the acrylic acid (AA) component can not be strictly necessary. By proper formulation design and processing, polysaccharide SAPs can be equally or even better performing than AA-containing SAPs in sanitary napkins. Fully biodegradable sodium alginate (SA)-based SAPs are prepared through ionic cross-linking by CaCl2 and introduced in female pads. The optimal solution concentrations (SA 8% w/v, CaCl2 0.25% w/v in water) and reaction time are identified, and addition of cellulose nanocrystals (CNC) at different weight contents (0-3 w%) is tested. Morphology, physico-chemical properties, rheology, free swelling capacity (FSC), centrifuge retention capacity, and weight loss in soil are assessed. Increasing CNC content decreases FSC. Rheology results demonstrate higher storage and loss moduli for SA-based SAPs versus commercial SAPs. The superior SA-SAP developed is used in varying amounts for manufacturing sanitary napkin prototypes, revealing that excellent menstrual fluid absorption, surpassing commercial pads. Replacing AA-based with polysaccharide-based SAPs would reduce the environmental impact of hygienic product waste.
Currently, the primary composition of fibrous filter materials predominantly relies on synthetic polymers derived from petroleum. The utilization of these polymers, as well as their production process, has a negative impact on the environment. Consequently, the adoption of air filter media fabricated from natural fibers would yield significant environmental benefits. Nowadays not only particle and odour capture performance but also ensuring a high energy efficiency and flame retardant properties in air filters is of utmost importance for automotive and HVAC filters. In this study, for the production of biodegradable and flame retardant air filters with a high quality factor, free standing gelatin/sodium alginate blend fibers were successfully produced via centrifugal spinning. The water-soluble mats were stabilized by physical methods using both thermal and ionic crosslinking. The CGCA (Crosslinked-Gelatin/Calcium Alginate) mat exhibited exceptional filtration performance for PM0.3 particles, achieving a 94.2 % efficiency rating at a pressure drop of 135 Pa. Moreover, blending of biopolymers and subsequent calcination provided V0 level flame retardancy according to UL94 standard. The preliminary biodegradation studies showed that proposed nanofibrous filters were completely degraded in soil in 7 days.
Microbial seed coatings serve as effective, labor-saving, and ecofriendly means of controlling soil-borne plant diseases. However, the survival of microbial agents on seed surfaces and in the rhizosphere remains a crucial challenge. In this work, we embedded a biocontrol bacteria (Bacillus subtilis ZF71) in sodium alginate (SA)/pectin (PC) hydrogel as a seed coating agent to control Fusarium root rot in cucumber. The formula of SA/PC hydrogel was optimized with the highest coating uniformity of 90 % in cucumber seeds. SA/PC hydrogel was characterized using rheological, gel content, and water content tests, thermal gravimetric analysis, and Fourier transform infrared spectroscopy. Bacillus subtilis ZF71 within the SA/PC hydrogel network formed a biofilm-like structure with a high viable cell content (8.30 log CFU/seed). After 37 days of storage, there was still a high number of Bacillus subtilis ZF71 cells (7.23 log CFU/seed) surviving on the surface of cucumber seeds. Pot experiments revealed a higher control efficiency against Fusarium root rot in ZF71-SA/PC cucumber seeds (53.26 %) compared with roots irrigated with a ZF71 suspension. Overall, this study introduced a promising microbial seed coating strategy based on biofilm formation that improved performance against soil-borne plant diseases.
Purpose Sodium alginate (Na-Alg) is a natural polysaccharide with a rich and renewable production that is widely used in the food, pharmaceutical and daily necessities industries, among other fields. The purpose of this study is to obtain a green and degradable shape memory material, calcium alginate (Ca-Alg) film was prepared and the mechanical properties, the shape memory effect of the film were investigated and confirmed. Design/methodology/approach The Ca-Alg films were prepared by Na-Alg, calcium chloride (CaCl2) solution, and flow extension method. Dissolve sodium alginate powder, remove bubbles, pour into petri dish, dry at 60 degrees C, add calcium chloride solution cross-linking and finally dry naturally. The effect of CaCl2 solution concentration on the mechanical properties of the films were investigated and discussed by universal tensile tester. The shape memory behavior and degradation performance of thin films were verified and studied by the fold-deploy shape memory test and soil embedding method, respectively. Findings The Ca-Alg films exhibited good mechanical and shape memory properties, with a 72.2% shape memory fixity ratio and a 92.3% shape memory recovery ratio, respectively. For a period of 120 days, the film treated with a 6 wt% CaCl2 solution degraded at a rate of approximately 53%. Research limitations/implications Shape memory polymers (SMPs) as intelligent materials are an important research direction for the development of modern high-tech materials. On the other hand, plastic pollution is a major problem today; as a result, preparing green degradable SMPs is essential. Originality/value This study synthesized transparent and degradable shape memory Ca-Alg films using Na-Alg and CaCl2 solution and the flow extension method.