Food packaging is one of the most commonly used materials today due to its affordability and convenience. However, this type of packaging is challenging to handle after use, leading to significant environmental waste since it is often made from petrochemical polymers that take a long time to decompose. Polyvinyl alcohol (PVA) is a low-cost, safe, and biodegradable polymer with high potential for food packaging, offering a solution to waste issues in the polymer industry. However, its limited hydrophilicity, bactericidal properties, and poor performance in humid conditions hinder its practicality. Enhancing the mechanical properties and water resistance of PVA-based composite films can significantly improve their applicability, particularly in food packaging. In this study, nanocomposite films based on PVA were reinforced with nanocellulose fiber (CNF) and Ag nanoparticles (AgNPs), and cross-linked using citric acid (CA) through the film casting method. The incorporation of CNF and AgNPs improved the structural integrity and thermal stability of the film, while CA crosslinking significantly enhanced water resistance and mechanical properties. The (PVA/CNF/Ag)-CA film exhibited the highest tensile strength (89.44 MPa), Young's modulus (3.29 GPa), and water contact angle (similar to 90 degrees), alongside the lowest water absorption (78.6 %) and a reduced water vapor transmission rate of 6.62 g x h(-1) x m(-2). Compared to pure PVA film, the resulting crosslinked nanocomposite films showed a 32.3 % increase in modulus and a 22.64 % increase in tensile strength. Additionally, the (PVA/CNF/Ag)-CA film exhibited higher thermal stability with 13 % more residue content than uncrosslinked counterparts, reduced moisture absorption, minimal swelling, and water insolubility. However, the CA crosslinking process promoted AgNP aggregation, reducing the antibacterial activity of the (PVA/CNF/Ag)-CA film against Staphylococcus aureus and Escherichia coli, and slowed down its biodegradation in soil. Nevertheless, after seven days of storage under both aerobic and anaerobic conditions, the nanocomposite coatings effectively minimized mass loss and microbial growth on fresh chili peppers. These results highlight the synergistic contribution of CNF/Ag reinforcement and CA crosslinking in enhancing the mechanical strength, thermal stability, and water resistance of PVA-based films for potential food packaging applications.

Environmental issues caused by plastic films promote the development of biodegradability packaging materials. Copper ion-modified nanocellulose films were prepared through a one-pot reaction and systematically investigated their structural characteristics, thermal stability, mechanical properties, antibacterial activity, and biodegradability. The results indicate that the film prepared by co-soaking CNCs and copper in NaOH solution for 12 h has favorable performance. Introduction of copper ions as crosslinkers increases tensile strength of film from 36.8 MPa to 56.4 MPa and water contact angle of film from 46 degrees to 92 degrees. Copper coordination also endows the film excellent antibacterial activity, inhibiting growth of Escherichia coli and Staphylococcus aureus. Moreover, biodegradability tests indicate that although the introduction of copper ions slightly reduce biodegradation rate of films, they could still be decomposed significantly within four weeks as burying in soil. This simple process for preparing cellulosic films with water resistance, thermal stable, antibacterial ability, and biodegradable shows potential application in flexible packaging film.

The growing demand for sustainable and environment-friendly materials has driven extensive research on biopolymers for applications in agriculture, food science, and environmental remediation. Among these, nanocellulose-hydrogel hybrids (NC-HHs) have gained significant attention as an innovative class of bio-based materials that uniquely combine the remarkable physicochemical properties of nanocellulose with the functional versatility of hydrogels. These hybrids are characterised by exceptional water retention, mechanical strength and biodegradability, enabling advances in precision agriculture, smart food preservation and contaminant remediation. This review provides a comprehensive understanding of the synthesis, properties, and multifunctional applications of NC-HHs, emphasising their innovative role in sustainability. In agriculture, NCHHs enhance soil moisture retention, support plant growth, and serve as carriers for controlled-release fertilizers, optimizing water and nutrient use efficiency. In the food industry, they enable intelligent packaging solutions that extend shelf life, monitor food freshness, and inhibit microbial growth. Additionally, NC-HHs present groundbreaking strategies for environmental remediation by effectively immobilizing pollutants in water and soil. Beyond summarizing recent advances, this review presents an in-depth mechanistic perspective on the interactions between NC and HH, critically evaluating their structure-property relationships, functional adaptability and application-specific performance. By integrating recent advances in nanocellulose functionalisation, polymer chemistry and the development of responsive hydrogels, this review critically examines the key technological innovations and future prospects of NC-HHs, underscoring their transformative potential in addressing global challenges related to food security, environmental sustainability, and sustainable agricultural practices.

The results of the study of plastic composites from degradable poly(3-hydroxybutyrate) P(3HB) and cellulose-containing natural materials of various origins are presented. For the first time, P(3HB) composites filled with bacterial nanocellulose (BNC) or wood (Pinus sibirica) flour (WF) were produced by melt pressing at 170 degrees C and 2000 Pa. The influence of the filler type and amount (30, 40, 50, 70 and 90 wt%) on the physicochemical and mechanical properties of the composites and their degradability in soil laboratory microcosms was revealed. The P(3HB)/WF composites compared with P(3HB)/BNC ones were thermally stable; their thermal degradation temperatures were 266 and 227 degrees C, respectively. Both composites had lower values of Young's modulus and fracture strength compared to P(3HB). As BNC content was increased, Young's modulus and fracture strength of the composites increased from 1831 to 14 MPa to 3049 and 19 MPa, in contrast to P(3HB)/WF, where the values decreased by a factor of 1.5-2.0. The half-life of composites with BNC and WF in soil was 180 and 220 days, respectively. Changes in the structure of the microbial community were determined as depending on the filler type; primary destructors among bacteria and fungi were isolated and identified. Environmentally friendly and completely degradable composites show promise as cellulose-plastic materials for practical application.

Cellulose micro-nanofibrils (CMNF) with different fibrillation levels were partially acetylated while preserving their morphological and native crystalline structure. The morphological changes due to fibrillation and chemical modification were observed using Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) and optical profilometry. The change in tensile and burst strength, barrier, and biodegradability profile were investigated which revealed that the mechanical properties of the unmodified CMNF films increased with increase in extent of fibrillation. However, the mechanical strength of the acetylated film decreased with the increase in degree of acetylation. The stretching or folding property of the film increased with the increase in both the fibrillation and acetylation. The contact angle value increased due to a higher degree of fibrillation and acetylation because they increased the hydrophobicity and consequently enhanced the air and water vapor resistance of the unmodified and modified CNF films. Furthermore, all films exhibited the highest resistance against oil and grease, and the biodegradability test substantiated that CNF films were compostable in soil. In total, this work expresses new pathways to enhance the barrier properties of biodegradable CNF films by regulating the degree of fibrillation and acetylation, thus can emerge as sustainable alternatives for packaging and agriculture applications.

Soil and water pollution are current global environmental and agricultural challenges, adversely affected by ineffective industrial waste treatment before discharging into the environment combined with inefficient long-term inputs of fertilizers. The development of targeted fertilizers delivery vehicles, sufficient soil/water remediation, and contamination detection systems using eco-friendly technologies become critically important. Due to their high specific surface area, biocompatibility, easiness of operation, and high performance, nanomaterials-based controllable soil fertility promoters, adsorbents, sensors, and photocatalysts are promising tools for soil/water pollution prevention, remediation, and monitoring. Altogether, crystallinity, hydrophilic-tunable surface chemistry, and 3D forming ability of nanocellulose (NC), in addition to biodegradability, regeneration ability, and mechanical properties of NC nanocomposite hydrogels (NCHs), lead to advancing promising soil/water nanohydrogels-based targeted fertilizers delivery vehicles, adsorbents, co-adsorbents/co-sensors, and co-adsorbents/co-photocatalysts. In these systems, NCHs introduce 3D rigid porous scaffolds for homogenous dispersing/fixing of functional groups, fertilizers, fluorescence sources, and photocatalysts. Also, they present stimuli-responsive networks for fertilizer regulation in soil, and matrixes with extra active sites enabling contaminates immobilization/degradation. This review outlines an update of the most recent potential utilization of functionalized NCHs-based soil/water adsorbents, photocatalysts, sensors, and slow/targeted fertilizers release vehicles. An in-depth discussion of surface pretreatments-modifications used to improve their performance, fabrication methods, application properties, and working mechanisms was discussed. The potential limitations and future perspectives on using NCHs in fertilizer/water management, soil/water remediation, and detection are highlighted.

Food packaging films play a vital role in preserving and protecting food. However, due to their nonbiodegradability, conventional packaging materials have led to significant environmental pollution. To overcome this hurdle, we have developed safe, innovative, sustainable and biodegradable packaging materials that can effectively extend the shelf life of food. In this study, two types of cellulose materials cellulose nanofibers (CNF) and carboxymethyl cellulose (CMC) with complementary roles were combined to prepare nanocellulose composite films with high transparency (90.3 %) of a certain thickness (30 +/- 0.019 mu m) by solution casting method, and their mechanical properties were further optimized by the addition of plasticizer-glycerol (Gly) and cross-linking agent-glutaraldehyde (GA), so as to maintain the strong tensile strength (approximate to 112.60 MPa) and better malleability (4.12 %). In addition, we loaded the natural active agent tea polyphenols (TPs) with different concentrations to study the inhibition effect on E.coli and S.aureus and to simulate food packaging. Finally, we also found that the synthesized nanocellulose composite films can also achieve rapid degradation in a short time through soil burial, water flushing and immersion. The excellent performance demonstrated in this study provides reference value for further replacing petroleum-based materials with biomass materials in the field of food packaging.

Flammability is a fatal drawback for sustainable packaging materials made from cellulose and its derivatives. Incorporating inorganic nanomaterials is a viable approach to improve the fire-resistant property. However, due to the aggregation of inorganic fillers and weak interactions between components, incorporating inorganic nanomaterials always had an adverse impact on the mechanical properties and optical transparency of cellulosebased nanocomposites. Herein, we presented a robust, biodegradable, and flame-retardant nanocomposite film composed of TEMPO-oxidized cellulose nanofibers (TOCNFs) and inorganic hydroxyapatite nanowires (HNWs). Both TOCNFs and HNWs possessed one-dimensional microstructure and could form unique organic-inorganic networks microstructure. The organic-inorganic networks interact through physical intertwinement and multiple chemical bonds, endowing nanocomposite film with outstanding mechanical properties. This nanocomposite film showed a tensile strength of 223.68 MPa and Young's modulus of 9.18 GPa, which were superior to most reported cellulose-based nanocomposite. Furthermore, this nanocomposite film demonstrated exceptional thermal stability and flame-retardant feature attributed to the inorganic framework formed by HNWs. This nanocomposite film also possessed a high optical transmittance even when HNWs content reached 30 % and could be decomposed quickly in soil. By employing organic-inorganic interpenetrating network structure design and multiple bonding interaction, cellulose-based nanocomposites can overcome inherent limitations and attain desirable comprehensive properties.