Having porous structure, large surface area, and high carbon content of biochar facilitates interface bonding of polylactic acid (PLA) composites, but uneven dispersion by its irregular morphology is becoming a new challenge in damaging properties. Based on this, the novelty of this study is using carbon quantum dots (CQDs) to overcome the performance defects of caused PLA composites by biochar while the ultimate goal is to reveal the influence mechanism of CQDs on structure, characteristics, and properties of PLA composites based on disclosing the forming mechanism of CQDs. It was found that adding CQDs accelerated the degradation of PLA from the results of Phosphate Buffer Saline (PBS) degradation, hydrolysis, and soil degradation. PLA/CQDs composite films also showed better thermal properties due to the excellent thermal stability of CQDs, and nucleation effect of CQDs should be responsible for the improvement of PLA crystallization. Additionally, having good activity, regular morphology, and uniform size of CQDs facilitated uniform dispersion and good interface combination in PLA system and thereby improved the tensile strength, tensile modulus, and elongation at break simultaneously. As a comparison, the tensile strength, tensile modulus, and elongation at break of 1 wt% PLA/CQDs composite films are 55.00 MPa, 1.76 GPa, and 9.84 %, this provides a promising, sustainable, and eco-friendly solution for reinforcing PLA composites.

Development of bio-based active packaging systems for lipid stabilization presents critical importance in preserving lipid integrity and ensuring food safety. Zein/citric acid (Z/CA) composite films containing grape seed ethanol extract (GSEE) (0-8% w/w) were prepared by the solvent casting method. The structural, functional, and environmental properties of the films, including physical and chemical properties, mechanical properties, antioxidant capacity, antibacterial activity, oxidation inhibition effect, and biodegradability, were comprehensively characterized and evaluated. Progressive GSEE enrichment significantly enhanced film thickness (p < 0.05), hydrophobicity, and total phenolic content, while increasing water vapor permeability by 61.29%. Antioxidant capacity demonstrated radical scavenging enhancements of 83.75% (DPPH) and 89.33% (ABTS) at maximal GSEE loading compared to control films. Mechanical parameters exhibited inverse proportionality to GSEE concentration, with tensile strength and elongation at break decreasing by 28.13% and 59.43%, respectively. SEM microstructural analysis revealed concentration-dependent increases in surface asperity and cross-sectional phase heterogeneity. Antimicrobial assays demonstrated selective bacteriostatic effects against Gram-negative pathogens. Notably, the composite film containing 6 wt% GSEE had a remarkable restraining effect on the oxidation of lard. The soil degradation experiment has confirmed that the Z/CA/GSEE composite film can achieve obvious degradation within 28 days. The above results indicate that the Z/CA/GSEE composite material emerges as a promising candidate for sustainable active food packaging applications.

Preparation and characterization of biopolymer-based packaging materials have significantly gained importance because of sustainability, biodegradability, and eco-friendly nature. In this study, novel wheat gluten (WG)/cloisite 30B (C30B) organoclay-based bionanocomposite (BNC) films were prepared by solution casting method at various C30B concentrations (5%, 10%, and 15%). X-ray diffraction and field emission scanning electron microscopy revealed intercalation/exfoliation of C30B sheets into the WG matrix. WG-C30B 10% film was thermostable. It showed low surface roughness along with higher water barrier properties and surface hydrophobicity. The tensile strength values of WG and WG-C30B 10% films were found to be 0.7 +/- 0.02 and 1.11 +/- 0.01, respectively, indicating improvement in mechanical properties. WG-C30B 10% film demonstrated antibacterial activity against both Staphylococcus aureus and Salmonella enterica. Shelf life of green grapes was monitored under different conditions: 4 degrees C, ambient conditions, and 42 degrees C. WG-C30B 10% film proved effective in extending shelf life up to 18 days under ambient conditions. More than 50% of the bionanocomposite films were degraded in agricultural soil within 2 weeks, while completely degraded in sewage sludge soil after a few days. WG-C30B 10% film appeared to be promising regarding the demonstrated physico-chemical and antibacterial properties. This report would be useful in preparing biodegradable biopolymer-based packaging materials.

In a world increasingly focused on environmental sustainability and the imperative of efficient waste management, innovative approaches in material science are becoming crucial. This research is centered on the synthesis of cellulose nanocrystals (CNCs) from post-use exam waste paper and the development of a chitosan-CNC (CS-CNCs) composite. CNCs were successfully isolated from waste paper by alkali treatment, bleaching, and sulfuric acid hydrolysis with FTIR and XRD analyses confirming successful extraction and a crystallinity index of 66.3%. TEM imaging revealed CNCs with a unique spherical morphology and diameters of 6-7 nm, significantly smaller than those reported in existing literature. Chitosan (CS), derived from shrimp shell waste, was integrated into the CNCs to form a composite thin film. This film, as revealed by SEM, had a homogeneous and consistent structure. The CS-CNCs composite demonstrated superior mechanical properties, with tensile strength increasing from 17.74 megapascal (MPa) in pure CS film to 22.08 MPa in composite, indicating its potential for robust and sustainable packaging materials. Soil degradation tests over 25 days showed a 24.7% degradation for CS-CNCs films, compared to 9.09% for CS films, underscoring their enhanced biodegradability. The composite exhibited notable antibacterial activity against Escherichia coli, suggesting its suitability for medical and hygiene applications. The measured contact angle of 80.4 degrees indicates the film's hydrophilicity, making it an excellent candidate for self-cleaning surfaces, such as textiles and windows. Remarkably, the CS-CNCs composite demonstrated exceptional photocatalytic degradation of Alizarin Red S dye, achieving 99.7% efficiency in 45 min, far surpassing the 87% efficiency of standalone CS films. The study showcases the green-synthesized CS-CNCs composite from waste paper offering an effective, eco-friendly, and economical approach for wastewater treatment due to its dual capabilities in dye degradation and antibacterial properties, while also opening avenues for its prospective application in self-cleaning surfaces, environmental remediation, and packaging thereby presenting a sustainable and economical solution for environmental cleanup and material innovation.

This research investigates the production of biodegradable films using a combination of gum odina (GO) and polyvinyl alcohol (PVA) with varied ratio. The study focuses on the chemical, physical, and mechanical properties of PVA-GO composite films, emphasizing how versatile and biodegradable they may be for a range of packaging applications. Solvent-cast PVA-GO films with different ratios are subjected to a methodical analytical process to determine several parameters like mechanical qualities, thermal stability, biodegradability in soil, contact angle, transparency, water vapor permeability, moisture content, thickness, density, water solubility, microstructure, and FTIR analysis. The outcomes demonstrate that GO improves UV barrier qualities and water vapor permeability. Additionally, the films showed notable biodegradability, acceptable thermal stability, and mechanical qualities. In short, PVA-GO films can provide an eco-friendly packing substitute with adaptable qualities fit for a range of uses. Therefore, this research may further contribute promising information in the field of biodegradable packaging materials in the future. image

Eco-friendly, bioactive and edible films from renewable resources are increasingly regarded as viable replacements for petroleum-based packaging. This study investigates the application of Ulva lactuca macroalgae powder (ULP) as an active additive in crab (Portunus segnis) chitosan-based films for natural food packaging. Films with ULP concentrations of 0.5, 1.5, and 2.5% were prepared using a solvent-casting method with glycerol as a plasticizer. Their physicochemical, mechanical, functional, and biological properties were evaluated comprehensively. Fourier-transform infrared spectroscopy revealed intermolecular interactions between ULP's polyphenolic compounds and the chitosan matrix, enhancing the films' structural integrities. ULP's incorporation reduced the moisture content, water solubility, lightness (L*), redness (a*), and whiteness index values while significantly (p < 0.05) increasing the yellowness (b*), total color difference (Delta E), yellowness index (YI), tensile strength (TS), and elongation at break (EB). The antioxidant activity improved in a concentration-dependent manner, as evidenced by the high free-radical scavenging capacity. Moreover, antimicrobial tests showed significant inhibitory effects against pathogenic strains. Biodegradability tests confirmed that the films decomposed entirely within 12 days under soil burial conditions, reinforcing their environmental compatibility. These results highlight the multifunctional potential of chitosan-ULP composite films, combining enhanced mechanical properties, bioactivity, and sustainability. By utilizing renewable and biodegradable materials, this work contributes to reducing waste and promoting resource efficiency, aligning with the principles of a circular economy and environmental preservation.

Although poly (lactic acid) (PLA) is a good environmentally-friendly bio-degradable polymer which is used to substitute traditional petrochemical-based polymer packaging films, the barrier properties of PLA films are still insufficient for high-barrier packaging applications. In this study, oxygen scavenger hydroxyl-terminated polybutadiene (HTPB) and cobalt salt catalyst were incorporated into the PLA/poly (butylene adipate-co-terephthalate) (PLA/PBAT), followed by melting extrusion and three-layer co-extrusion blown film process to prepare the composite films. The oxygen permeability coefficient of the composite film combined with 6 wt% oxygen scavenger and 0.4 wt% catalyst was decreased significantly from 377.00 cc mil m-2 day-1 0.1 MPa-1 to 0.98 cc mil m-2 day-1 0.1 MPa-1, showing a remarkable enhancement of 384.69 times compared with the PLA/PBAT composite film. Meanwhile, the degradation behavior of the composite film was also accelerated, exhibiting a mass loss of nearly 60% of the original mass after seven days of degradation in an alkaline environment, whereas PLA/PBAT composite film only showed a mass loss of 32%. This work has successfully prepared PLA/PBAT composite films with simultaneously improved oxygen barrier property and degradation behavior, which has great potential for high-demanding green chemistry packaging industries, including food, agricultural, and military packaging. (c) 2024 Institute of Process Engineering, Chinese Academy of Sciences. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co., Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Fenton cellulose nanofibrils (F-CNF) were prepared by Fenton oxidation with the followed homogenization and then F-CNF /PVA composite films with the F-CNF additives from 1% to 20% were prepared by solution casting method. Scanning electron microscopy (SEM), confocal laser scanning microscope (CLSM), Fourier transform infrared spectroscopy (FTIR), universal tensile testing machine, swelling property detection, thermogravimetric analysis and soil burial degradation rate test were used to characterize the microstructure, chemical structure, mechanical properties, hygroscopicity, thermal stability and biodegradability of the composites. The results showed that a large number of hydrogen bonds were formed between F-CNF and PVA molecules and an acetal reaction occurred. F-CNF can be uniformly dispersed in PVA matrix, and both have good interfacial compatibility. After the addition of F-CNF, the tensile strength and elastic modulus of the composite films were significantly improved, the water absorption of the composite material was reduced, and its thermal stability was improved. When the amount of F-CNF was 15%, the tensile strength and Young's modulus of the composite films were 65.27 MPa and 1460.32 MPa, respectively, which were 217.77% and 830.69% higher than those of pure PVA.

The alarming issue of food waste, coupled with the potential risks posed by petroleum-based plastic preservation materials to both the environment and human health necessitate innovative solutions. In this study, we prepared nanoemulsions (NEs) of chitosan (CS) and ginger essential oil (GEO) and systematically evaluated the effects of varying NEs concentrations (0, 10 %, 30 %, 50 %) on the physicochemical properties and biological activities of gelatin films. These films were subsequently applied to blueberry preservation. The scanning electron microscopy confirmed that the NEs were well-integrated with the Gel matrix, significantly enhancing the performance of the Gel films, including improvements of mechanical properties (tensile strength from 7.71 to 19.92 MPa; elongation at break from 38.55 to 113.65 %), thermal, and barrier properties (water vapor permeability from 1.52 x 10(-9)to 6.54 x 10(-10) g & sdot;m/Pa & sdot;s & sdot;m(2)). The films exhibited notable antibacterial and antioxidant activities due to the gradual release of GEO, thereby extending the storage life of blueberries. Moreover, the prepared composite films demonstrated excellent biodegradability and environmental friendliness, with the majority of the material decomposing within 30 days under soil microbial action. In conclusion, the active films loaded with NEs exhibit superior performance and hold significant potential for developing biodegradable materials for food preservation.

Carboxymethyl cellulose (CMC) has attracted considerable interest in research due to its exceptional film-forming properties and compatibility with biological systems. However, CMC films still suffer from mechanical brittleness and structural instability due to the rigid structure and many hydroxyl groups in practical applications. Herein, a nanocomposite film is reported, synthesized via inserting layered montmorillonite (MMT) into a CMC and guar gum (GG) hydrogen bond networks. Incorporating MMT with a high aspect ratio increases the number of hydrogen bond cross-linking sites among constituents, thereby enhancing the mechanical strength and toughness of nanocomposite films. The resulting CMC/GG(10)/MMT6 films show flexibility (elongation at break 83.5 +/- 4.35%), high tensile strength (53.5 +/- 1.10 MPa), and high toughness (32.16 +/- 1.04 MJ/m(3)). These films also integrate hydrophobic (up to 84.78 degrees) and high-temperature resistance (50% degradation temperature up to 304 degrees C) properties to adapt to complex practical application environments. Moreover, they exhibit excellent ultraviolet shielding performance under a wide wavelength range (200-320 nm). Soil burial experiments showed that all the films could be assimilated into the soil within about 9 days. This approach offers a simple and promising route for producing biodegradable CMC-based films for food packaging.