Synergistic Crosslinking Research Articles

Effect of epigallocatechin gallate/transglutaminase synergistic cross-linking on the flavor of surimi gels

Epigallocatechin gallate (EGCG) and transglutaminase (TGase) can improve the structure of surimi gels, and have a significant impact on their texture and flavor quality. The formation and release of volatile odors due to EGCG, TGase and EGCG/TGase synergistic cross-linking of surimi gels were investigated. The characteristic flavor components of the surimi gels were aldehydes. Compared with the blank group, the total content of volatile compounds in EGCG, TGase, and EGCG/TGase groups decreased by 14.43, 11.69, and 20.07 %, indicating that the flavor of EGCG/TGase group was more affected by EGCG than by TGase. The free fatty acid content in these groups decreased by 17.28, 1.30, and 43.98 mg/100 g, indicating that the degree of fatty acid degradation in the EGCG/TGase group was lower during a two-stage heating process, which may be ascribed to EGCG's inhibition of oxidative degradation of fatty acids, thereby reducing the production of flavor substances.

Enhanced high-temperature energy storage performance in all-organic dielectric films through synergistic crosslinking of chemical and physical interaction

Advanced electronic devices and energy systems urgently require high-temperature polymer dielectrics that can offer both high discharge energy density and energy storage efficiency. However, the capacitive properties of most polymers sharply deteriorate at elevated temperatures, due to the significant rise in leakage current density and energy loss. Herein, a new design approach is adopted to fabricate high-temperature polyetherimide (PEI) dielectrics with chemical and physical cooperative crosslinking networks, the dual-crosslinked PEI dielectrics are prepared through amine crosslinking agent and the electrostatic interaction of oppositely charged phenyl groups between triptycene (TE) and PEI chain segments. Benefiting from the increased crosslinking sites, the dual-crosslinked PEI films achieve the simultaneously enhancement in Tg, modulus and bandgap compared to un-crosslinked and single-crosslinked polymers. Meanwhile, the PEI with dual-crosslinked network displays higher chain packing density, effectively reducing the mean motion pathways of charge carriers and the conduction loss inside polymer dielectric. Consequently, the dual-crosslinked PEI containing 0.25 wt% TE delivers an outstanding discharge energy density of 2.69 J/cm3 and retains excellent cyclability after 100,000 charge–discharge cycles at 200 ℃. Additionally, finite element analysis and molecular dynamics simulation further confirm that less Joule heat and tighter chain structure are formed in the dual-crosslinked polymer dielectric. This research offers a novel methodology to prepare high-performance polymer dielectrics for high-temperature applications.

Cross‐Scale Interface Engineering for Fabricating Super‐Strong and Super‐Tough Aramid nanofiber film

AbstractPoly (p‐phenylene terephthalamide) (PPTA), known for its exceptional mechanical properties under the brand name Kevlar, finds extensive use in high‐performance applications despite the challenges it presents in processing and integration with other materials. Existing top–down methods for preparing PPTA composites result in significantly reduced strength (<200 MPa) and toughness (<10 MJ·m−3) due to insufficient interfacial interactions, limiting their application. Here, a cross‐scale interface engineering strategy is reported for fabricating super‐strong and super‐tough PPTA composite films. At the microscale, a synergistic crosslinking strategy of physical entanglement and hydrogen bonding to crosslink PPTA nanofibers is employed. At the macroscale, the network using a cyclic freeze–thaw and the stretch‐drying method is reinforced. The PPTA nanofiber composite film is super‐strong (854.6 MPa), super‐tough (106.2 MJ·m−3), and has a high‐temperature resistance (300 °C). Moreover, the bottom–up approach enables the direct synthesis of PPTA nanofibers, significantly reducing the preparation time from 7 days to 0.5 h. Furthermore, it is demonstrated that the composite film can be integrated into a robust and intelligent sensing‐display device that responds to external mechanical and heat injuries for firefighter's protection. This work provides an efficient strategy for fabricating high‐performance PPTA composites, paving the way for their practical use as durable protective materials.

Dynamic Recyclable High-Performance Epoxy Resins via Triazolinedione-Indole Click Reaction and Cation-π Interaction Synergistic Crosslinking.

Thermosetting plastics exhibit remarkable mechanical properties and high corrosion resistance, yet the permanent covalent crosslinked network renders these materials challenging for reshaping and recycling. In this study, a high-performance polymer film (EI25-TAD5-Mg) was synthesized by combining click chemistry and cation-π interactions. The internal network of the material was selectively constructed through flexible triazolinedione (TAD) and indole via a click reaction. Cation-π interactions were established between Mg2+ and electron-rich indole units, leading to network contraction and reinforcement. Dynamic non-covalent interactions improved the covalent crosslinked network, and the reversible dissociation of cation-π interactions during loading provided effective energy dissipation. Finally, the epoxy resin exhibited excellent mechanical properties (tensile strength of 91.2 MPa) and latent dynamic behavior. Additionally, the thermal reversibility of the C-N click reaction and dynamic cation-π interaction endowed the material with processability and recyclability. This strategy holds potential value in the field of modifying covalent thermosetting materials.

Effect of Chemical Composition of Metal-Organic Crosslinker on the Properties of Fracturing Fluid in High-Temperature Reservoir.

To investigate the effect of the chemical composition of a metal-organic crosslinker on the performances of fracturing fluid in high-temperature conditions, four zirconium (Zr) crosslinkers and one aluminum-zirconium (Al-Zr) crosslinker with a polyacrylamide were used. The crosslinkers possessed the same Zr concentration, but they differed in component amounts and the order of the addition of the crosslinker components, leading to different chemical compositions in the crosslinkers. The fracturing fluids prepared by different tested crosslinkers were compared in terms of properties of rheological behavior, sand-carrying ability, microstructure, and gel breaking characteristics. The results showed that the fracturing fluids prepared by zirconium lactic acid, ethanediamine, and sorbitol crosslinkers offered the slowest viscosity development and highest final viscosity compared to the zirconium lactic acid crosslinker and the zirconium lactic acid and ethanediamine crosslinker. The zirconium sorbitol, lactic acid, and ethanediamine crosslinker exhibited a faster crosslinking rate and a higher final viscosity than the zirconium lactic acid, ethanediamine, and sorbitol crosslinker; the crosslinker showed crosslinking density and crosslinking reactivity, resulting in more crosslinking sites and a higher strength in the fracturing fluid. The Al-Zr-based crosslinker possessed better properties in temperature and shear resistance, viscoelasticity, shear recovery, and sand-carrying ability than the Zr-based crosslinker due to the synergistic crosslinking effect of aluminum and zirconium ions. The tertiary release gelation mechanism of the Al-Zr-based fracturing fluid achieved a temperature resistance performance in the form of continuous crosslinking, avoiding the excessive crosslinking dehydration and reducing viscosity loss caused by early shear damage. These results indicated that the chemical compositions of metal-organic crosslinkers were important factors in determining the properties of fracturing fluids. Therefore, the appropriate type of crosslinker could save costs without adding the additional components required for high-temperature reservoirs.

Enhanced probiotic viability in innovative double-network emulsion gels: Synergistic effects of the whey protein concentrate-xanthan gum complex and κ-carrageenan

In this study, the whey protein concentrate and xanthan gum complex obtained by specific pH treatment, along with κ-carrageenan (KC), were used to encapsulate Lactobacillus acidophilus JYLA-191 in an emulsion gel system. The effects of crosslinking and KC concentration on the visual characteristics, stability, mechanical properties, and formation mechanism of emulsion gels were investigated. The results of optical imaging, particle size distribution, and rheology exhibited that with the addition of crosslinking agents, denser and more homogeneous emulsion gels were formed, along with a relative decrease in the droplet size and a gradual increase in viscosity. Especially when the concentration of citric acid (CA) was 0.09 wt%, KC was 0.8 wt%, and K+ was present in the system, the double-network emulsion gel was stable at high temperatures and in freezing environments, and the swelling ratio was the lowest (9.41%). Gastrointestinal tract digestive treatments and pasteurization revealed that the probiotics encapsulated in the double-network emulsion gel had a higher survival rate, which was attributed to the synergistic cross-linking of CA and K+ biopolymers to construct the emulsion gels. Overall, this study highlights the potential of emulsion gels to maintain probiotic vitality and provides valuable insights for developing inventive functional foods.

Supramolecular assembly of dual crosslinked nanocomposite polysaccharides hydrogel: Integration of injectable, self-healing, and pH-responsive platform for sustained delivery of polyphenols

This study introduces an innovative approach in the field of biomaterials through the development of a multifunctional, printable scaffold designed for the advanced delivery of polyphenols. Addressing challenges of burst-release, poor compounds solubility and bioavailability, we engineered a supramolecular-assembled dual crosslinked hydrogel combining fucoidan (F) and chitosan (CS) encapsulating nanoliposomes. The novel integration of dibenzaldehyde-terminated PEG (DB) within the hydrogel, created a synergistic crosslinking through the formation of the covalent Schiff base bonds and physical interactions which enhanced the hydrogel's overall characteristics. Tailoring F content (DBCS-F), allowed the crosslinking density modulation, yielding a robust gel network structure with enhanced mechanical properties, evidenced by a remarkable compressive stress resistance of 1.73 MPa at 60% strain, coupled with high compressive resilience (79.31% stress recovery after 6 cycles), surpassing single crosslinked hydrogel (DBCS). The rheological analysis further confirmed the hydrogel's improved viscoelasticity, stable network structure, and shear-thinning behavior, affirming its excellent injectability and suitability for 3D printing applications. Most notably, the incorporation of catechin/juglone-loaded nanoliposomes contributed to a pH-responsive sustained release of polyphenols in simulated gastrointestinal conditions. The developed dual crosslinked hydrogel, integrating injectability, self-healing, and pH-responsiveness presents a significant advancement in biomaterials and holds a promising approach for the fabrication of personalized 3D printed scaffolds aimed for sustained and targeted polyphenols release.

Camellia meal-based adhesive with synergistic crosslinking of physical and chemical interaction for preparing aldehyde-free, anti-mildew, water-resistant wood-based composites

Wood adhesives containing toxic aldehyde-based adhesives play a vital role in the performance of wood-based panels, while the mechanical properties and water and mildew resistance of aldehyde-free adhesives are lacking. In this study, a high-strength aldehyde-free adhesive was constructed via a combination of physical and chemical crosslinks. Inexpensive alum was used to ensure a high degree of crosslinking and to increase the crystallinity. Metal ions in alum opened the protein helix, exposed the active groups, increased the number of hydrogen bonds, and ultimately improved the internal physical crosslinking ability of the adhesive. The compound formed by the Schiff base reaction formed coordination bonds with metal ions, thus forming a covalently-crosslinked network. The high-strength polymer produced in this study contained multiple physical and covalent crosslinks, resulting in significantly improved mechanical properties of the adhesive. Its water-resistant adhesive strength reached 1.96 MPa, which was 180.2% higher than that of ordinary phytogenic protein adhesive (0.69 MPa), and it can still reach 1.28 MPa after hot water circulation soaking experiment. The adhesive also possessed antifungal properties and flame-retardant capabilities, achieving a V-1 rating in the UL-94 test. This strategy expanded the application of phytogenic protein adhesives in environmentally friendly wood composite materials by replacing synthetic resins that released formaldehyde and provided an economical and feasible industrial scale production method for the preparation of high strength, water, and mildew resistant, flame retardant indoor and outdoor wood-based panels.

Synergistic crosslinking effect of hydroxyethyl cellulose and montmorillonite on the improvement of mechanical and electrochemical properties of polyvinyl alcohol hydrogel

Flexible solid-state zinc-ion battery is promising energy technology with low cost, excellent performance, and safety. However, the mechanical properties of flexible electrolytes are severely limited. Here, hydroxyethyl cellulose (HEC) and montmorillonite (MMT) were introduced into a polyvinyl alcohol (PVA) matrix to prepare a novel composite hydrogel using a repeated freeze-thaw method. Both organic HEC and inorganic MMT could form hydrogen bonds with PVA molecular chains, acting as crosslinkers to construct a well-networked hydrogel structure. The synergistic effect of these two crosslinkers significantly enhanced the mechanical properties of the composite hydrogel. The composite hydrogel prepared with 3 wt% HEC and 2 wt% MMT (denoted as P–H3%-M2%) exhibited a 242.6% increase in tensile strength, 78.6% increase in elongation at break, and 970.1% increase in compressive strength compared to pure PVA hydrogel. P–H3%-M2% hydrogel also demonstrated a high electrolyte uptake rate (199.15%) and ion conductivity (24.6 mS cm−1). When assembled in a Zn symmetric battery, it maintained stable operation for 3000 h with a low polarization voltage of approximately 70 mV. Furthermore, P–H3%-M2% hydrogel assembled in a Zn//MnO2 battery exhibited a discharge specific capacity of 218 mAh g−1 at a current density of 0.15 A g−1, with 91% capacity retention after 450 cycles. At a higher current density of 1.5 A g−1, it showed a discharge specific capacity of 108 mAh g−1, which is 4.5 times higher than that of the PVA hydrogel battery, demonstrating excellent rate performance.

A High-Performance Food Package Material Prepared by the Synergistic Crosslinking of Gelatin with Polyphenol-Titanium Complexes.

This study aims to enhance gelatin film performance in the food industry by incorporating polyphenol-titanium complexes (PTCs) as crosslinkers. PTCs introduce multiple linkages with gelatin, including coordination and hydrogen bonds, resulting in synergistic crosslinking effects. This leads to an increased hydrodynamic volume, particle size, and thermal stability of the gelatin films. Compared to films crosslinked solely by polyphenols or titanium, PTC-crosslinked gelatin films exhibit significant improvements. They show enhanced mechanical properties with a tensile strength that is 1.7 to 2.6 times higher than neat gelatin films. Moreover, these films effectively shield UV light (from 82% to 99%), providing better protection for light-sensitive food ingredients and preserving lutein content (from 74.2% to 78.1%) under light exposure. The incorporation of PTCs also improves film hydrophobicity, as indicated by water contact angles ranging from 115.3° to 131.9° and a water solubility ranging from 31.5% to 33.6%. Additionally, PTC-enhanced films demonstrate a superior antioxidant ability, with a prolonged polyphenol release (up to 18 days in immersed water) and a higher free radical scavenging ability (from 22% to 25.2%). Overall, the improved characteristics of gelatin films enabled by PTCs enhance their performance, making them suitable for various food packaging applications.

Molecule structure design by synergistic crosslinking in the PVA matrix and its physical properties regulation

Environmentally friendly polyvinyl alcohol (PVA) has a broad range of potential applications in membrane science. This article describes the co-crosslinking used to adjust the water resistance and swelling level of PVA molecules and broaden their applications. To integrate functional groups and carbon chains in the PVA matrix, the crosslinking agents glutaraldehyde (GA) and ammonium persulfate (APS) were used, the complexity of the PVA crosslinking structure can be dramatically increased. The results showed that the crosslinked PVA film's water resistance and thermal stability qualities have improved. The synergistic crosslinked film's swelling percentage, maximum decomposition temperature, and diffusion constant altered from 590 %, 242.9 ℃, and 1.13 × 10−11 m2/s to 129 %, 344.7 ℃, 0.02 × 10−11 m2/s respectively. The synergistic crosslinked film's swelling percentage, maximum decomposition temperature, and diffusion constant were altered with the molecule structure design. This method can give a novel reference to the performances design of hydrophilic polymers in different applications.

Enhancement of Starch Gel Properties Using Ionic Synergistic Multiple Crosslinking Extrusion Modification.

Crosslinking is a promising method to modulate the gel properties of food-grade starch gels. Still, the poor crosslinking effect of a single type of crosslinker limits the application of this method in starch gel modification. In this study, an Ca2+ synergistic multiple crosslinking modification method was proposed to prepare crosslinked starches with good gel properties and setting. The rheological properties of the samples were tested. The modified sample (SC-Ca-N3, G' = 1347 ± 27) showed a 79% improvement compared to the starch without synergistic crosslinking modification (SC-N, G' = 752 ± 6). The elastic modulus of starch gels can be adjusted by changing the degree of the crosslinking reaction. The results of nonlinear rheological Lissajous curve analysis showed that the synergistically crosslinked gel system strongly resisted deformation. In addition, the microstructure of the modified samples was characterized using scanning electron microscopy. The XPS, FTIR, and XRD results indicated that multiple molecular forces participate in the synergistic crosslinking reaction.

Modulation of the properties of starch gels by a one-step extrusion modification method based on Ca2+-citric acid synergistic crosslinking

Citric acid (CA) is a green and safe food-grade crosslinking agent for starch, but its high crosslinking temperature limits its application. In this study, a “one-step” extrusion modification method based on Ca2+-esterification synergistic crosslinking was proposed for the preparation of high gel performance crosslinked starch at low temperatures (90 °C). The linear and nonlinear rheological properties of crosslinked starch were comprehensively characterized, and the enhancement effect of synergistic crosslinking reactions on starch gel properties was quantitatively studied. The results show that the elastic modulus of the synergistically crosslinked starch (SC-0.5Ca2+, G' = 3116 ± 36) was significantly increased by 879 % compared to the elastic modulus of starch without synergistically crosslinked modification (SC, G' = 318 ± 9). The elastic modulus of starch gels can be adjusted by changing the ion concentration. Nonlinear rheological Lissajous curve analysis results show that the synergistic crosslinked gel system has a stronger anti-deformation ability. In addition, the honeycomb porous structure and smaller pore size distribution of the synergistic crosslinked gels were characterized using scanning SEM. The XPS, FTIR and XRD results suggest that the synergistic crosslinking enhancement effect may involve various molecular forces such as electrostatic attraction, hydrogen bonding and ester bonding.

Novel synergistic cross-linking ameliorate ready-to-eat sea cucumber deterioration and its quantum chemical analysis

Synergistic cross-linkers could improve the taste acceptability of ready-to-eat sea cucumber (RSC). Besides, the hardness of RSC was increased by 331.00% and 266.87% after synergistic cross-linking. Synergistic cross-linking treatment could ameliorate the non-enzymatic degradation of RSC collagen and polysaccharides. Gaussian calculations results showed that dipeptides containing asparagine residues may have different reaction pathways. The main cleavage pathways of CH3CO-Asn-Gly-NHCH3 (NG) might be water-assisted side chain cyclization, stepwise cyclamide hydrolysis via a Gemdiol Intermediate, deamination, and peptide bond breakage. The relative free energy of cyclamide hydrolysis process of NG was increased by 8.2 kcal/mol after synergistic cross-linking. The mass spectrometry results showed that typical peptides could cleavage at NG, CH3CO-Asn-Lys-NHCH3 (NK) and CH3CO-Asn-Leu-NHCH3 (NL) sites after heating, which justified the breakage pattern of peptides in Gaussian calculations. It can offer a comprehensive theoretical basis for the processing of the ready-to-eat sea cucumber with storage stability.

Construction and properties of a carbon dots-decorated gelatin-dialdehyde starch hydrogel with pH response release and antibacterial activity

An antibacterial carbon dot hydrogel (GDSS-PCD) was constructed based on gelatin, dialdehyde starch (DS) and carbon dots (S-PCDs). The formation mechanism of GDSS-PCD hydrogels was attributed to the synergistic cross-linking of hydrogen bonds and dynamic covalent bonds. With increasing S-PCD content, the mechanical and rheological properties of GDSS-PCD hydrogels can be improved, and the micropore size becomes denser. GDSS-PCD hydrogels had pH-dependent swelling and degradation behavior, with a high swelling rate under acidic conditions and relatively low swelling under neutral and alkaline conditions. The cumulative release of S-PCDs from the same hydrogel in an acidic environment was higher than that in an alkaline environment, indicating that the GDSS-PCD hydrogel had a pH-dependent controlled release ability. The release behavior of S-PCDs conformed to the first-order kinetic release model (R2 > 0.95), and the release mechanism was related to Fickian diffusion. The synergistic antibacterial mechanism of GDSS-PCD hydrogels against Staphylococcus aureus suggested that bacterial metabolism leads to an acidic culture environment, which releases S-PCDs and destroys the bacterial cell membrane for antibacterial purposes. In GDSS-PCD hydrogels, S-PCDs play the main antibacterial role, and the hydrogel plays a synergistic role in trapping bacteria. Carbon dot hydrogels are promising materials to fulfil the functions of antibacterial and controlled release in the food and biomedical fields.

Low temperature preparation of high-performance citric acid crosslinked starch gels with adjustable properties based on cationic esterification synergistic crosslinking

Citric acid (CA) is a commonly used crosslinking agent for good-grade starch gels, but its high crosslinking temperature limits its application. Recent attempts to prepare CA-crosslinked modified starch gels (SC) at low temperatures have resulted in low crosslinking degrees that do not meet application requirements. This study presents a new method for stable preparation of high-strength Fe3+-CA synergistic crosslinked starch gels at low temperatures (90 °C), carried out in a stable and controlled multi-physical field high-shear reaction environment. The enhancement effect of synergistic crosslinking reaction on starch gel properties was quantitatively characterized by linear and nonlinear rheological properties. The results showed that the elastic modulus of synergistically crosslinked modified SC-0.6Fe3+ (G' = 1082.71 ± 21.50) at 0.1% strain was significantly increased by 491.57% compared to the elastic modulus of SC (G' = 183.04 ± 13.32) without synergistic crosslinking modification. SC-0.6Fe3+ demonstrated the largest elastic Lissajous ring area, indicating stronger resistance to deformation in the synergistic crosslinked gel system. Additionally, adjusting the cation concentration allowed for flexible modulation of the rheological properties of starch gels. SEM and N2 adsorption data revealed that SC-0.6Fe3+ had a denser honeycomb porous structure and a smaller pore size distribution. FTIR, XRD, DSC, and TGA results suggested that the synergistic crosslinking enhancement effect might be achieved through electrostatic attraction, hydrogen bonding, ionic dipole interactions, and ester bonding. Our work provides an effective strategy for batch preparation of adjustable high-performance food-grade crosslinked starch gels in low-temperature environments.

Low-temperature self-healing polyurethane adhesives via dual synergetic crosslinking strategy

Abstract Damage to polymer adhesives is one of the most common reasons for structural integrity damage of composite solid propellants. The introduction of self-repairing technology into the adhesive is expected to solve this problem. However, at low temperatures, the self-repairing and mechanical properties of the materials are greatly impaired, thereby limiting the application of self-repairing adhesives in composite solid propellants. In this study, based on the dual synergistic crosslinking strategy, a polyurethane adhesive exhibiting excellent self-healing and mechanical properties at low temperatures was successfully prepared. The adhesive exhibited high self-repairing efficiency and ultra-long elongation at break at low temperatures. Specifically, at a low temperature of −40°C, the self-repair efficiency was over 70% and the elongation at break was over 1,400%, which were much higher than the results of the control group. Moreover, the strength was comparable to that of the control group. This polyurethane adhesive shows excellent self-healing and mechanical properties at low temperatures and is expected to provide the strong self-healing ability and mechanical properties for composite solid propellants, alleviating the problem of structural integrity damage.

A Strategy of Thiolactone Chemistry to Construct Strong and Tough Self-Healing Supramolecular Polyurethane Elastomers via Hierarchical Hydrogen Bonds and Coordination Bonds

Self-healing elastomers with extended service life and enhanced reliability have attracted extensive attention in recent years due to their broad application in fields such as protective coatings, wearable electronics, shape memory materials, and health-care monitoring. However, it is challenging to simultaneously optimize the mechanical properties (strength and toughness) and self-healing capacity of the elastomers. Herein, thiolactone chemistry was delicately used as a bridge to address this conundrum by incorporating 2-ureido-4[1H]-pyrimidinone (UPy) motifs and imidazole ligands into the side chains of linear polyurethane. The synergistic cross-linking of UPy H-bonds and Zn2+-imidazole coordination afforded a robust supramolecular network to significantly improve the strength. Meanwhile, these dynamic cross-linking points acted as sacrificial bonds for energy dissipation under external stress, which played a dominant role in toughening. Therefore, the resultant elastomer (PU-Im-UPy-Zn) exhibited a tensile strength of 9.1 MPa, a breaking elongation of 989%, and toughness up to 62.1 MJ m–3. In addition, the reversible exchange of hierarchical hydrogen bonds (single H-bonds between the carbamate groups and quadruple H-bonds of the UPy dimers) and coordination bonds as well as the high mobility of side chains were conducive to repairing under mild conditions. The superficial scratches completely disappeared at 60 °C, and a satisfactory healing efficiency of 78% was observed after 24 h. This work provides some insights into future design of self-healable supramolecular polyurethane elastomers integrated with conspicuous strength and toughness.

Effect of glycerol triglycidyl ether on the dimensional stability and flexibility of photographic gelatine films

The gelatine emulsions used in historical photographs can shrink and become brittle under alternating dry–wet environmental conditions, which would result in curling and fracture of the gelatin paper photographs, thereby degrading their quality and threatening the long-term inheritance of such cultural heritage. To improve the stability and flexibility of gelatine films under dry–wet cycling, glycerol triglycidyl ether (GPE) was employed as a synergistic crosslinking and plasticising agent. The plasticising effect of GPE on the dimensional stability and flexibility of gelatine films in alternating dry–wet environments was firstly studied. Gelatine films with different contents of GPE were prepared and their dimensional changes during dry–wet cycling were investigated. The results indicate that GPE greatly enhances the dimensional stability of the films during cycling. By analysing the swelling behaviour, molecular structure, mechanical strength, fracture cross-sections, and other properties of the gelatine–GPE films, it was confirmed that the addition of GPE greatly reduces the moisture absorption and swelling of gelatine and improves its moisture stability. Furthermore, benefiting from GPE as a crosslinking agent, the mechanical strength and flexibility of the gelatine films were both enhanced. In this study, the modification of gelatin film by GPE provides experimental evidence for the subsequent research on the application of restoration and conservation for the gelatin paper photographs.

3D Hierarchical Porous Carbon Aerogel Electrocatalysts Based on Cellulose/Aramid Nanofibers and Application in High-Performance Zn–Air Batteries

Three-dimensional (3D) carbon aerogels (CAs) are composed of interconnected networks and emerge as appealing platforms for the combination of heteroatom dopants, defective sites, and hierarchical porous structures. Here, we propose an effective and sustainable strategy to construct TOCNF/ANF-Cd hydrogels/aerogels using TEMPO-oxidized cellulose nanofibers (TOCNFs), thermally stabilized aramid nanofibers (ANFs), and low-boiling-point Cd2+. Hierarchical porous N-doped aerogel catalysts (N/CA-Cd) with TOCNF/ANF synergistic cross-linking were obtained by moderate temperature pyrolysis. Apart from serving as a source of N, ANF also improves carbon retention and graphitization, increasing the electrical conductivity of carbon aerogels. Due to the spatially continuous structure and multiscale porous structure and abundant N dopants and edges/defects, the as-obtained N/CA0.5-Cd carbonaceous catalysts manifest an impressive electrocatalytic efficacy with a positive half-wave potential (0.86 V). In particular, the Zn–air batteries assembled with N/CA0.5-Cd as the air cathode catalyst have an excellent peak power density of 186 mW cm–2 and a splendid specific capacity of 730 mA h g–1.