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Blending modification is used to improve the hemocompatibility of cellulose acetate (CA) dialysis membranes while endowing the CA membrane with endotoxin scavenging and antibacterial capabilities. First, polydopamine (PDA) and polyethylenimine (PEI) are used as negatively charged and positively charged moieties, respectively, together with cellulose nanocrystals (CNCs) to construct mixed charge CNCs (PEI‐PDA@CNCs). Then PEI‐PDA@CNCs is blended with the CA casting solution, and the modified CA dialysis membrane is prepared through a phase inversion process. Through biocompatibility, adsorption, antibacterial, and filtration experiments, various properties of PEI‐PDA@CNCs modified CA membrane (PDCA) are systematically tested. The results show that the PDCA membrane exhibited good blood compatibility and noncytotoxicity. At the same time, the PDCA membrane has antibacterial properties and excellent endotoxin adsorption capacity. Compared with the CA membrane, the clearance rates of PDCA membrane for Staphylococcus aureus and Escherichia coli reach 54.0% ± 1.5% and 52.9% ± 5.9% respectively. In the dynamic adsorption experiment, the adsorption capacity of PDCA membrane for endotoxin increases to 2322.1 ± 45.9 EU/g. The research results indicate that PEI‐PDA@CNC‐modified multifunctional CA membrane with endotoxin adsorption and antibacterial properties has potential application prospects in the fields of hemodialysis and blood purification. [ABSTRACT FROM AUTHOR]

A bio‐based nanocomposite optical film was obtained through a simple sol‐gel process and solution casting. The dispersion effect of cellulose nanocrystals (CNCs) gel and the optical properties, mechanical performance and thermal stability of CNC‐doped cellulose triacetate (TAC) films (TAC−X) were systematically evaluated. The results show that CNCs can be well dispersed in hydrophobic organic solvents and TAC matrices through the sol‐gel process. TAC−X film has excellent optical properties, its light transmittance is above 92 %, its haze value and birefringence are low, ranging from 0.21±0.01 % to 0.38±0.02 %, and (1.64±0.26)×10−6 to (2.49±0.50)×10−6 respectively. When doped with 2 wt % CNCs, the tensile strength and Young's modulus of the TAC‐2 film were 33.0 % and 30.1 % higher than those of the pure TAC film, separately. At the same time, the TAC−X film also maintains good thermal stability, with its glass transition temperature and maximum decomposition temperature falling between 215–216 °C and 366–368 °C respectively. The simple sol‐gel process provides a convenient and efficient way to use CNCs doping to enhance the physical and mechanical properties of TAC optical films. [ABSTRACT FROM AUTHOR]

Shape memory polyimides (SMPI) with adjustable shape recovery temperatures have been paid much attention in both fundamental research and practical applications. However, the intrinsically electrical insulation of SMPIs limits their applications. In this article, the electrically conductive shape memory polyimide‐polyaniline (SMPI‐PANI) composite with interpenetrating networks was synthesized by in situ polycondensation. Compared with pure SMPI, the electrical resistivity of SMPI‐PANI composites reduced by about 12 orders of magnitude when the PANI content was 15 wt%. The addition of PANI had less influence on the glass transition temperature and storage modulus in glassy state. But the storage modulus of SMPI‐PANI composites in rubbery state was over 40 times higher than that of pure SMPI, indicating that SMPI‐PANI composites have higher stiffness during shape recovery. The SMPI‐PANI composites demonstrate excellent shape memory performance with shape fixation ratio higher than 97% and shape recovery ratio higher than 93%. The SMPI‐PANI composites also have good thermal stability with the effective decomposition temperatures higher than 150°C. The SMPI‐PANI composite in our work is a potential material for deployable aerospace structure. [ABSTRACT FROM AUTHOR]

Artificial antioxidants are synthesized from fossil sources and are now widely used in the polymer, food, and cosmetics industries. The gradual depletion of fossil resources makes it practically significant and necessary to produce green antioxidants from renewable lignocellulosic resources. Herein, short‐time hydrothermal (STH) treatment was developed for production of lignin‐derived polyphenol antioxidants (LPAs) from poplar wood under conditions of high temperature and high pressure. LPA yields from 21.5 to 37.6 % on the basis of lignin in untreated wood were obtained by STH treatments as result of lignin depolymerization at 190–200 °C and 10 MPa in 5–8 min. Depolymerization reactions were confirmed by the much lower molecular weight of LPA (1076 g mol−1) than that of native lignin (4094 g mol−1). NMR spectroscopy revealed the structural features of lignin in the isolated LPA, namely syringyl and guaiacyl units with well‐preserved interunit linkages. A Folin–Ciocalteu assay indicated that each LPA molecule contained 5.4 phenolic hydroxyl groups on average, much more than other technical lignins. The remarkable antioxidant ability of LPA was verified by the radical‐scavenging index of 53.5–67.3, much higher than 0.2–11.1 of the commercial antioxidants butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA). STH treatment only requires water and heat for production of high‐value antioxidant, which provides a green and sustainable method for the utilization of lignocelluloses. [ABSTRACT FROM AUTHOR]

Whole valorization of carbohydrate and lignin from biomass was achieved by rapid flow‐through fractionation (RFF) within 15 min. Wheat straw was effectively deconstructed into its principle components without degradation by using easily recyclable aqueous formic acid (72 wt %) at 130 °C. The obtained cellulose‐rich solid showed a nearly complete glucan recovery and 73.8 % glucose conversion after enzymatic hydrolysis. Xylan also reached full recovery with negligible furfural formation with a sum of 80 % of oligo/mono xylose in spent liquor and 20 % of xylan remaining in the solid. Up to 75.4 % lignin was dissolved in the spent liquor and further fractionated into water‐insoluble (WIL) and water‐soluble lignin (WSL) by dilution with water. WIL showed a non‐condensed and well‐preserved structure with 84.5 % β‐O‐4 remaining, which is believed to be beneficial for catalytic conversion into low‐molecular‐weight chemicals and fuels. The concentration of employed formic acid was below the formic acid/water azeotrope, and therefore the reaction medium could be restored through simple distillation. Together with the joint valorization of lignin and carbohydrates, the presented RFF is a promising process for sustainable biorefinery. Whole valorization of carbohydrate and lignin from biomass is achieved by rapid flow‐through fractionation within 15 min. Wheat straw is effectively deconstructed into its principle components without degradation by using easily recyclable aqueous formic acid (72 wt %) at 130 °C. The obtained cellulose‐rich solid shows a nearly complete glucan recovery and 73.8 % glucose conversion after enzymatic hydrolysis. [ABSTRACT FROM AUTHOR]