Structure−Adhesion Relationship in Citric Acid-Crosslinked Cellulose Based Adhesives

Structure–thermal–morphological correlation in starch–PVA reinforced cactus mucilage bio-based composite films

This study presents a systematic investigation of the structural, thermal, and morphological characteristics of starch–PVA reinforced cactus bio-based composite films using FTIR, DSC, XRD, TGA, DMA, and SEM analyses. FTIR results suggested enhanced intermolecular hydrogen-bonding interactions among starch, PVA, and cactus-derived polysaccharides, with possible minor ester-link formation in the presence of citric acid. DSC analysis showed a glass transition temperature (Tg) in the range of 38–40 °C and a minor endothermic transition near 83 °C associated with bound moisture relaxation. The thermal transitions observed using the PerkinElmer DSC 9 were reproducible across replicate measurements, indicating good thermal consistency of the developed composite system. XRD analysis indicated a predominantly amorphous morphology with limited semi-crystalline domains and a crystallinity index of approximately 23.32%. TGA results suggested improved thermal stability relative to plasticized starch systems, while DMA results indicated moderate storage-modulus retention and viscoelastic stability over the investigated temperature range. SEM observations of tortuous crack propagation pathways and localized deformation mechanisms. The combined results indicate that the developed composite exhibits balanced thermal and structural performance and potential for sustainable flexible bio-based material applications. However, additional mechanical, durability, water-resistance, and comparative performance studies are necessary to evaluate its suitability as a leather substitute.

Microstructural insights and mechanical properties of physically crosslinked starch hydrogels via two-way amylose regulation.

Physical starch hydrogels have attracted significant attention due to their biodegradability and biocompatibility as clean-label hydrogels. In this work, we investigate the combined effect of maize starch amylose content and concentration on the formation of physically crosslinked low- and high-amylose hydrogels, prepared through a three-step physical process (swelling, gelatinization, retrogradation). Rheological characterization, including steady-state and dynamic measurements, was used to evaluate the texture profile analysis (TPA), hardness, fluid release and consistency coefficient (K). High-amylose maize hydrogels display 5-7 fold increase in hardness and 5-16 fold decrease in cohesiveness, with the dynamic mechanical loss tangent (tan δ) value being 0.12 for the hardest high-amylose studied sample. The microstructure and the correlation to the mechanical properties, retrogradation and syneresis were investigated by complementary scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). The role of hydrogen bonding between water molecules and polysaccharide chains with different order of organization, is highlighted. Our results provide insight into starch re-organization, including the formation of single-stranded amylose helices (V-amylose) within the crystalline and amorphous regions. Overall, we demonstrate that the mechanical properties and syneresis behavior of starch-based hydrogels could be effectively tailored by the proposed two-way amylose regulation, offering a promising strategy for developing bioinks for 3D printing in functional food applications.

Effects of Different Lignin Contents and Water Contents on the Performance of DES-Based Hydrogels

This study fabricated choline–acrylic acid deep eutectic solvent (DES) hydrogels via in situ free-radical polymerization and systematically investigated the individual and co-optimization effects of lignin dosage and water content on the chemical structure, micromorphology, compressive mechanical properties, swelling behavior, and thermal stability of the hydrogels. This work quantitatively uncovers the co-optimization mechanism between the two variables in modulating crosslink density and pore architecture, thereby filling a research gap in the dual-factor co-optimization of biomass-based DES hydrogels. The results reveal that a moderate lignin dosage (0.02 g) generates abundant dynamic hydrogen bonds, densifying the crosslinked network and raising the maximum compressive stress from 0.378 MPa to 0.426 MPa, whereas excessive lignin triggers molecular aggregation and deteriorates mechanical performance. Higher water content dilutes crosslinking sites, reduces network compactness, boosts the swelling ratio while lowering compressive strength, and exerts negligible impacts on thermal degradation characteristics. FTIR analysis confirms that lignin participates in network formation solely through non-covalent hydrogen bonds, without forming new covalent bonds. A comprehensive performance evaluation identifies the optimal formulation as 0.02 g lignin and 60 g water. Although this two-factor optimization strategy provides clear experimental and theoretical guidance for designing sustainable soft materials, the present work still has limitations, including the use of only static laboratory characterizations, with no cyclic mechanical measurements or aging assessments. This study advances the customized performance tuning of lignin-derived DES hydrogels and facilitates the high-value valorization of lignin, which is promising for multifunctional green-material applications, including adsorption, flexible electronics, and biological carriers.

Synthesis and investigation of superabsorbent polymer networks based on AMPS and VPA monomers

Glyoxal-crosslinked acacia gum hydrogel reinforced with graphene oxide and zinc ferrite for antibacterial and biomedical applications

The development of multifunctional hydrogels with balanced mechanical strength, swelling behavior, cytocompatibility, and antibacterial performance remains a key challenge in wound-dressing applications. In this study, a glyoxal-crosslinked acacia gum (AG) hydrogel reinforced with graphene oxide (GO) nanosheets and zinc ferrite (ZnFe₂O₄) nanoparticles was developed as a tri-component nanocomposite system. The incorporation of GO and ZnFe₂O₄ within the crosslinked AG network produced formulation-dependent structural and functional changes. The peak compressive strength was numerically higher in the final formulation (0.682 vs. 0.173 MPa), while the equilibrium swelling ratio decreased significantly from 463% to 292%. Rheological analysis showed elastic-dominant behavior, indicating stable gel-like viscoelastic properties under the tested conditions. Biological evaluation demonstrated high extract-based cytocompatibility toward MG-63 cells. Furthermore, preliminary antibacterial testing showed activity against Staphylococcus aureus and Escherichia coli , with inhibition values of 99.0% and 93.4%, respectively, in the representative CFU dataset. The proposed membrane-perturbation and oxidative-stress-related mechanisms are literature-supported and were not directly validated in this study. Overall, the ternary formulation showed higher peak compressive strength, significantly lower equilibrium swelling, favorable extract-based cytocompatibility, and preliminary antibacterial activity under the tested conditions. These findings support further investigation of this material as an antibacterial wound-dressing candidate following additional biological validation.

Photopolymerization of sustainable HEMA-citronellol copolymer hydrogels: in silico evaluation, physicochemical properties, and antibacterial performance