In this study, xylan-based double-network (DN) hydrogels (xylan-based DN gels) with excellent mechanical properties were prepared using acrylic acid and acrylamide (AM) based on a DN approach. The first layer network was obtained by grafting and crosslinking polyacrylic acid (PAA) molecular chains onto xylan with ammonium persulfate (APS) as the initiator and N, N'-methylenebisacrylamide (MBA) as the crosslinking agent; this network was subsequently immersed into an aqueous AM monomer in the presence of APS and MBA for the preparation of the second layer network. The results showed that the double networks were crosslinked by covalent bonds and that the mechanical properties of the xylan-based DN gels were enhanced. Thus, the xylan-based DN gels exhibited a maximum compression stress of 24.9 MPa. The xylan-based DN gels could also recover 97% of their original height after 15 repeated compression cycles; this indicates that the xylan-based DN gels possessed high resistance to friction and wear. Therefore, the prepared xylan-based DN gels have considerable potential for tissue engineering applications.

In this article, a facile two-step activation method, coupled with phosphoric acid (H₃PO₄)-assisted pretreatment and followed KOH activation, was reported for constructing hierarchical porous carbon (HPC) materials derived from lignin. The introduction of H₃PO₄, cross-linked with lignin sources generated phosphate (and/or polyphosphate) ester groups throughout the lignin structure, which endowed the pre-activated intermediate char (IC) with a hierarchical porous structure. Such phosphate esters contributed to the multi-scale pore structure within the pre-activated IC, which was beneficial for the uniform distribution and impregnation of subsequent KOH activators, thus leading to the formation of HPC materials. The as-prepared HPC exhibited a large specific surface area (SSA) of 1345.1 m²/g, which ensures the accessibility of the ion diffusion pathways. The supercapacitors integrated with HPC delivered a high specific capacitance of 241 F/g (in a three-electrode system) and outstanding rate capability with an 80.9% capacitance retention from 0.5 A/g to an ultra-high current density of 50 A/g.

The potential reactions between natural polysaccharides and iodine and their products have been explored for a long time. Due to the complex factors that can influence these reactions, a clear-cut mechanism has not yet been developed. Starch-iodine complexes, especially the amylose-iodine complex, are the most investigated of the polysaccharide-iodine reactions, and the study of this reaction can be used as a basis for the investigation of other polysaccharide-iodine reactions. In this paper, significant aspects of the reaction were introduced, including the influence of the polysaccharide structure on the properties of the resulting complexes, the relationship between the concentration of CaCl₂ and formation of the final products, as well as the form of the polyiodides in these complexes. The interior structure and the surface morphology of the complexes were discussed, along with the progress in research related to this reaction.