Green Semi-IPN Hydrogels by Direct Utilization of Crude Wood Hydrolysates

Crude and unmodified acetylated galactoglucomannan containing wood hydrolysate (WH) was directly incorporated into a semi-interpenetrating network (semi-IPN) composed of up to 60% renewable polymers. Semi-IPNs were produced by a facile and green synthetic pathway through cross-linking modified carboxymethylcellulose in the presence of at least 30%(w/w) WH, via free radical copolymerization with acrylic acid and <i>N</i>,<i>N</i>′-methylenebis­(acrylamide). FTIR verified the presence of WH interlaced with CMC in the semi-IPN, and the highly porous microscopic structure of the networks was confirmed by SEM. The gelation process of these networks was monitored in situ, and their individual “gel point” (the <i>G</i>′-<i>G</i>″ crossover) was determined by in situ rheological measurements. Semi-IPN hydrogels with various swelling ratios (<i>Q</i> = 20–225) were obtained within 2.8–20 min of a cross-linking reaction

Thiolated Hemicellulose As a Versatile Platform for One-Pot Click-Type Hydrogel Synthesis

A one-pot synthetic methodology for the thiolation of <i>O</i>-acetyl-galactoglucomannan (AcGGM) was developed to merge hemicellulose chemistry with “click” chemistry. This was realized by the AcGGM-mediated nucleophilic ring-opening of γ-thiobutyrolactone via the activation of the polysaccharide pendant hydroxyl groups. The incorporation of thiol functionalities onto the hemicellulose backbone was visualized by ¹H and ¹³C NMR spectroscopy and was assessed by an Ellman’s reagent assay of the thiol groups. The versatility of the thiolated AcGGM was elaborated and demonstrated by conducting several postmodification reactions together with hydrogel formation utilizing thiol–ene and thiol-Michael addition “click” reactions. The one-pot synthesis of thiolated AcGGM is a straightforward approach that can expand the applications of hemicelluloses derived from biomass by employing “click” chemistry