A series of cellulose grafted alternating cyclic anhydride (CA) and epoxide (EPO) copolyesters (cell- g -P(CA-alt-EPO)) have been prepared in the novel DBU/DMSO/CO 2 cellulose solvent system. The DBU acted both as a reagent for cellulose dissolution and as a catalyst for ring-opening copolymerization (ROCOP) of cellulose with EPO and CA. The structural features and thermal performances of cell- g -P(CA-alt-EPO) were characterized via MALDI-TOF, FT-IR NMR, TGA, DSC and XPS. Perfectly alternating sequence distributions and controlled molecular weights of a series of cell- g -P(CA-alt-EPO) were easily achieved by a variation of the CA or EPO. The cell- g -P(CA-alt-EPO) also had satisfactory UV-absorbing properties and cellulose grafted phthalic anhydride and glycidyltrimethylammonium chloride exhibited outstanding antibacterial behavior. Antibacterial activity against Escherichia coli and Staphylococcus aureus were 96.7% and 99.4% respectively. Thus, cell- g -P(CA-alt-EPO) with good solubility, melt processability, UV absorption and antibacterial properties have potential applications in UV-shielding and antibacterial agent fields.
Polyvinyl chloride (PVC) is the world’s third-most widely manufactured thermoplastic, but has the lowest recycling rate. The development of PVC-like plastics that can be depolymerized back to monomer contributes to a circular plastic economy, but has not been accessed. Here, we develop a series of chemically recyclable plastics from the reversible copolymerization of cyclic anhydride with chloral. The copolymerization is highly efficient through the anionic or cationic mechanism under mild conditions, yielding polyesters with tunable structure and properties from multiple commercial monomers. Notably, these polyesters manifest mechanical properties comparable to PVC and polystyrene. Meanwhile, such polyesters are flame-retardant like PVC due to high chloride content. Of significance, these polyesters can be depolymerized back to starting monomers at high temperatures owing to the reversibility of the copolymerization, leading to a circular economy. Overall, the readily available monomers, simple synthesis, advantageous performance, and practical recyclability make the polymers promising for applications.
In this study, a new method for preparing macroporous rigid agarose microspheres was developed by one-step pre-crosslinking method with cyclic anhydride. Three different cyclic anhydrides, namely, maleic anhydride, succinic anhydride, and glutaric anhydride, were used to pre-crosslink agarose. The reaction temperature and the amount of cyclic anhydride in the pre-crosslinking process were optimized to endow agarose with stronger cross-linking. Under the optimal cross-linking condition, macroporous rigid agarose microspheres with homogeneous particle size were successfully obtained by adjusting emulsification method. Cryo-scanning electron microscopy was used to characterize the morphology of cross-linked agarose gel and microspheres. The addition of cyclic anhydride increased the gel aperture of cross-linked agarose microspheres, thereby making the macropores in the microspheres more dense and enhancing the mass transfer in the particles. Under low pressure , the cross-linked agarose microsphere column can effectively separate model proteins at linear flow rates three times higher than the agarose microsphere column. These results indicate that the developed agarose microspheres are a promising high-speed chromatographic medium.
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