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Chitosan is a polysaccharide resulting from chitin deacetylation. It has demonstrated interesting characteristics in the field of adhesion but loses most of its adhesive resistance in moist environment. A chemical crosslinking of chitosan with genipin has been implemented to improve its adhesive properties in the presence of water. The study of crosslinking kinetics using rheology revealed its dependency on crosslinking rate and chitosan concentration. The capacity of the chitosan-genipin systems for water absorption has been quantified as their Free Swelling Capacity. The cross-linkage of chitosan by genipin (1% w/w) decreased significantly its ability for water absorption. Finally, the adhesive strength of several chitosans be they supplemented or not with genipin and/or glycerol used as plasticizer have been performed on Thick Adherent Shear Test samples of beech wood according to standard EN 204:2016 and EN 205:2016. The chitosan adhesive formulation containing genipin and glycerol exhibits the better adhesive properties on wood and presents higher water resistance compared to the native chitosan formulation. [ABSTRACT FROM AUTHOR]

The purpose of this study is to determine the rheological properties of cross-linked inulin solutions in two different polymerization degrees (native and degree of polymerization of >23%). Thus, the effect of cross-linking, a new approach applied to support a specific property (stabilization) of inulin, which has many benefits, has been demonstrated. Sodium hexametaphosphate was used as a cross-linking agent at three different ratios (0.375%, 0.500%, and 0.750%). The cross-linked inulin solutions were lyophilized, and the lyophilized mixture was then reconstituted at 25 °C and 45 °C to obtain cross-linked inulin solutions with 1% and 5% (w/v) concentrations. The control samples (native and with a high degree of polymerization) were treated similarly without a cross-linking agent. The samples were subjected to a dynamic frequency sweep test in the range of 0.01–10 Hz as well as shear viscosity measurements at 1–500/s shear rates for the determination of rheological properties. The thixotropic curves were analyzed as the shear rate increased from 0.1/s to 300/s in the first 120 s (up curve), and then decreased to the same point in the subsequent 120 s. Results indicated that cross-linking increased inulin solution viscosity, particularly at 5% concentration, and solubility. Solutions with 5% inulin containing 0.750% and 0.375% cross-linker yielded the highest viscosities at 45 °C and 25 °C, respectively. Samples with 5% inulin concentration exhibited solid-like behavior in the oscillation test. Thixotropic curves revealed antithixotropy at low shear rates and thixotropy at high shear rates. The study demonstrated the impact of cross-linking on inulin stabilization, providing insights for future applications. Results indicated that cross-linking increased inulin solution viscosity, particularly at 5% concentration, and solubility. Solutions with 5% inulin containing 0.750% and 0.375% cross-linker yielded the highest viscosities at 45 °C and 25 °C, respectively. Samples with 5% inulin concentration exhibited solid-like behavior in the oscillation test. Thixotropic curves revealed antithixotropy at low shear rates and thixotropy at high shear rates. The study demonstrated the impact of cross-linking on inulin stabilization, providing insights for future applications. [ABSTRACT FROM AUTHOR]

The use of the cross-linked marine seaweeds Lessonia nigrescens Bory and Macrocystis integrifolia Bory to remove 2-nitrophenol and 2-chlorophenol from aqueous solutions at room temperature was investigated. The effect of the initial pH, adsorbent dose, and initial concentration of the pollutant were evaluated in batch experiments. The mathematical adsorption models of Langmuir and Freundlich show a mixed adsorptive mechanism of both phenolic compounds by the algae. The calculated parameters demonstrate a high adsorbent to pollutant affinity ratio, indicating the potential effectiveness of these marine seaweeds in the removal of these phenolic compounds from diluted aqueous solutions. [ABSTRACT FROM AUTHOR]

A modified cashew nut shell oil coating film (CNSO-CF) was produced from the biomass of the oil obtained from the nut of Anacardium occidentale Linn . It dries more quickly than the conventional CNSO-CF. It is, therefore, more suitable to mass production on assembly lines. The modified CNSO-CF was analyzed by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), and its structures were compared with those of the conventional CNSO-CF and of urethane coating film. It was found that the modified CNSO-CF had a urethane coupling structure in addition to the same structures as the conventional CNSO-CF: the methylene cross-linked and autoxidative side chain-side chain C─C coupling structures. The addition of the urethane coupling structure accelerates the drying rate and expresses the most important functions for industrial use – extreme hardness and insolubility. [ABSTRACT FROM AUTHOR]