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.

To meet polymeric material sustainability requirements of the modern polymer industry, a novel diphenyl-based monomer, dimethyl 2,2'-((carbonylbis(4,1-phenylene))bis(oxy))diacetate (DPBD), was prepared from 4,4'-dixydroxybenzophenone, derived from potentially bio-sourced 4-hydroxybenzoic acid. The diester monomer DPBD was polymerized with either 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, or 1,4-cyclohexanedimethanol as aliphatic diols to afford aliphatic/aromatic copolyesters (P1-P4). The copolyesters were characterized using gel permeation chromatography, differential scanning calorimetry, thermogravimetric analysis, dynamic mechanical analysis, and tensile testing, as well as biodegradation and earthworm acute toxicity assays. The effects of diol carbon chain length and cyclic diol monomers on polyester properties were investigated. From the results, the weight-average molecular weight (Mw) of the polyesters ranged from 37.5 to 45.5 kg/mol, glass transition temperature (Tg) ranged from 65 to 78 degrees C, initial thermal decomposition temperature (Td,5%) varied from 324 to 353 degrees C, yield strength varied from 45 to 56 MPa, and elongation-at-break ranged from 215 to 290%. The properties can be adjusted by tuning the monomer structure, which induced a degradation rate of up to 4.6% after incubation in soil for 30 weeks, in contrast to poly(ethylene terephthalate) (PET) which showed no degradation under the same conditions. The ecotoxicity of the polyesters to earthworms remained low, even at high concentration polymer concentration tested (4000 mg/kg soil), the survival rate was above 82%. Therefore, polyesters offer a good combination of structure-to-property serving as potential alternatives to petroleum-based materials.

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.

To address the depletion of non-renewable resources and align with the principles of green development, researchers increasingly turned to natural plant extracts to synthesise bio-based waterborne polyurethanes (BWPU) as a sustainable alternative to conventional petroleum-derived BWPUs. Although BWPU demonstrated low emissions and non-toxic characteristics, they still exhibited limitations in heat resistance and relatively reduced biodegradability. Thus, to enhance the overall performance of BWPU, sorbitan monooleate (SP) and quercetin (QC) were incorporated into the formulation of hybrid waterborne polyurethane (CWPU). As natural bio-based hybrid materials, QC and SP facilitated the formation of cross-linking networks and hydrogen bonds, enhancing intermolecular interactions and conformational stability in self-cross-linking CWPU. The research concentrated on investigating the chemical structure, mechanical properties, thermal characteristics, and biodegradability of CWPU. The results demonstrated that the introduction of QC constructed a dense cross-linking network, leading to an increase in elongation at the break of CWPU from 460 % to 864 %. Under the condition of 5 % weight loss (T5%), the thermal stability of CWPU was significantly enhanced, with the decomposition temperature increasing from 200 to 243 degrees C. In addition, after degradation in soil and in a 0.6 % lipase PBS buffer for 28 days, the weight of CWPU decreased to 53 % and 48 %, respectively. CWPU can optimise the utilisation of BWPU in biomedical and packaging applications, thereby contributing to innovations in environmentally friendly materials.

The extensive use of non-biodegradable and petroleum derived polymers in industry exacerbates environmental problems associated with plastic waste accumulation and fossil resource depletion. The most promising solution to overcome this issue is the replacement of these polymers with biodegradable and bio-based polymers. In this paper, novel biocomposites were prepared from bio-based polyamide 5.6 (PA56) with the addition of olive stone powder (OSP) at varying weight concentrations by melt compounding method. The degradability of the prepared biocomposites is investigated through soil burial test, and assessed by reduction in their mechanical properties. The biodegradability of bio-based polyamide 5.6 is shown to be improved by addition of olive stone powder, and its effects on the properties of polymer matrix are elucidated. The Fourier transform infrared (FTIR) spectrum of the biocomposites indicate the successful incorporation of OSP into PA56 polymer matrix. After six-month soil burial test, scanning electron microscopy and FTIR show the degradation of PA56 through morphological and structural changes, respectively. Differential scanning calorimetry reveals the changes in the transition temperatures of the polymer matrix and an increase in crystallinity. Thermogravimetric analysis is used on the biocomposite to determine the fraction of its components, polymer and biofiller, and the results show that 2.67% (w/w) of the polyamide 5.6 is biodegraded at the end of the six-month soil burial.

In light of the growing plastic waste problem worldwide, including in agriculture, this study focuses on the usefulness of both conventional, non-degradable plastics and environmentally friendly bioplastics in the agricultural sector. Although conventional plastic products are still essential in modern, even ecological agriculture, the increasing contamination by these materials, especially in a fragmented form, highlights the urgent need to search for alternative, easily biodegradable materials that could replace the non-degradable ones. According to the literature, polymers are widely used in agriculture for the preparation of agrochemicals (mostly fertilizers) with prolonged release. They also play a role as functional polymers against pests, serve as very useful super absorbents of water to improve crop health under drought conditions, and are commonly used as mulching films, membranes, mats, non-woven fabrics, protective nets, seed coatings, agrochemical packaging, or greenhouse coverings. This widespread application leads to the uncontrolled contamination of soil with disintegrated polymeric materials. Therefore, this study highlights the possible applications of bio-based materials as alternatives to conventional polyolefins or other environmentally persistent polymers. Bio-based polymers align with the strategy of innovative agricultural advancements, leading to more productive farming by reducing plastic contamination and adverse ecotoxicological impacts on aquatic and terrestrial organisms. On the other hand, advanced polymer membranes act as catching agents for agrochemicals, protecting against environmental intoxication. The global versatility of polymer applications in agriculture will not permit the elimination of already existing technologies involving polymers in the near future. However, in line with ecological trends in modern agriculture, more green polymers should be employed in this sector. Moreover, we highlight that more comprehensive legislative work on these aspects should be undertaken at the European Union level to guarantee environmental and climate protection. From the EU legislation point of view, the implementation of a unified, legally binding system on applications of bio-based, biodegradable, and compostable plastics should be a priority to be addressed. In this respect, the EU already demonstrates an initial action plan. Unfortunately, these are still projected directions for future EU policy, which require in-depth analysis.

A novel diester monomer synthesized from 4-hydroxybenzoic acid, a compound which can be derived from lignin, was used to obtain aliphatic-aromatic copolyesters (P1-P4) by melt polymerization with 1,4-cyclohexanedimethanol, and either 1,4-butanedioic acid, 1,6-hexanedioic acid, 1,8-octanedioic acid, or 1,12-dodecanedioic acid as aliphatic diacid. Structure-property relations for the copolyesters were established using FTIR and 1H NMR spectroscopy, gel permeation chromatography, differential scanning calorimetry, thermogravimetric analysis, dynamic mechanical analysis and tensile testing. The weight-average molecular weight (Mw) of the samples ranged from 41,400 to 48,300 g/mol. As the spacer length in the aliphatic diacid was increased, the glass transition temperature (Tg) decreased from 90 to 51 degrees C, the melting point (Tm) from 175 to 147 degrees C, the tensile modulus from 1800 to 980 MPa, and the yield strength from 76 to 54 MPa, while the elongation at break increased from 270 to 320%. The thermal stability of the copolyesters also decreased for longer aliphatic diacid spacers. The copolyester derived from 1,12-dodecanedioic acid displayed the highest degradation rate in artificial soil, with 4.4% degradation after 30 weeks, and low ecotoxicity in an earthworm viability test. These findings contribute to understanding structure-property relationships and the environmental impact of aliphatic-aromatic copolyesters as potential sustainable materials.

As sucrose is less expensive and more readily available than tannin, sucrose-based foams were prepared by incorporating furfuryl alcohol (FA) and glyoxal as a crosslinking agent to obtain sucrose-furan-glyoxal (SFG) resin. Ammonium dihydrogen phosphate (ADP) was then incorporated into SFG and foamed with azodicarbonamide (AC) to form SFGA foam. The study examined the chemical structures, morphology, mechanical properties, thermal properties and flame retardancy of the foams. The findings indicated that the SFGA foam exhibited a closed cell structure characterized by a smooth surface as well as high compressive strength and shore hardness. The closed structure of SFGA provides the foam with good thermal stability and excellent flame retardancy, as demonstrated by its limiting oxygen index (LOI) of 43.3 %. The combustion test demonstrated that the SFGA foam attained the UL-94 V-0 flame retardant classification. During the process of combustion, the primary volatile compounds identified were carbon dioxide, acetic acid, and oxanes. No toxic substances such as alkanes were detected. In addition to its outstanding flame retardant properties, SFGA foam is also capable of biodegradation. After being buried in soil for 30 days, it exhibited a weight reduction of 2.7 %. The SFGA foam underwent a weight reduction of 0.69 % in the laboratory when exposed to Penicillium sp for a duration of 20 days. The study proposed that sucrose can serve as a substitute for tannin in the production of rigid foam, which is suitable for insulation materials.

The market of epoxy resin-based adhesives is constantly growing in the automotive, electronics, and healthcare industries thanks to their unique features such as high bonding strength, durability, and corrosion resistance. In this work, alternative sustainable vitrimer adhesives, containing from 20 to 50 wt% of lignin microparticles, were prepared from epoxidized linseed oil (ELO) and a boronic ester dithiol crosslinker (DBEDT), in the absence of solvents and catalysts. The addition of unmodified commercial Kraft lignin to the composites directly influences their thermal and mechanical properties and determines their bonding capacity between several adherent substrates, also affecting the rewelding potential. The lignin-vitrimer composites and the corresponding neat vitrimer matrix exhibited values of lap shear strengths in the range of 9 to 17 MPa, when tested as adhesives with aluminum, stainless steel, and wood specimens, and good to excellent rewelding capability. The amount of lignin microparticles influences the balance between cohesive and adhesive forces during the separation of the adhered aluminum surfaces and the eventual joint failure. In the case of the composites with 20 wt% of lignin, lap shear strength remains constant even after four cycles of rebonding via compression molding, indicating that the best rewelding performance is associated with previous cohesive failure when the adhesive remains on both aluminum sheets' surfaces. In addition, the adhesion was preserved for 83 % of the initial value after 24 h immersed in water. Importantly, biodegradability in both soil and seawater was enhanced by the presence of the lignin filler. In summary, the simple preparation strategy of bio-based vitrimer composites coming from two natural sources could pave the way to green alternatives for industrial applications, such as epoxy-based adhesives.

Understanding the soil-root mechanical interaction is crucial to advancing the utilisation of vegetation as a nature-based approach to designing more stable slopes and resilient urban forestry against tree windthrown. Although numerical and analytical models for detailed analysis of soil-root interaction exist, these models are seldom validated due to the lack of field data and the significant challenges in quantifying such interactions due to the complex nature of root system. The centrifuge modelling technique is an effective alternative for unravelling the complexities of the hydromechanical behaviour of vegetated soils by recreating prototype stress levels in small-scale physical models and testing them under more controlled conditions. This work presents a critical review on existing centrifuge modelling methods for vegetated soils, paying particular attention on the (i) fundamentals of centrifuge modelling, where principles, scaling laws and applications relevant to modelling vegetated soils are detailed; (ii) methods for modelling soils, including choice of soil material and sample preparation; and (iii) methods for modelling roots by means of natural plants and root analogues, where the replication of root morphology, mechanical properties and capabilities of modelling transpiration effects are discussed. In every topic, the challenges that could further advance the centrifuge modelling of vegetated soils and the possible ways to address them are highlighted. Finally, the prospect for future studies is discussed, highlighting the potential to enhance the understanding of the underlying mechanisms amongst plant roots, soil, water and external loading.