Xueping Song

A flexible solid-state electrolyte for wide-scale integration of rechargeable zinc–air batteries

Rechargeable zinc–air batteries, having high energy densities and cost-effectiveness, are important environmentally-benign energy storage solutions. Here we developed a facile strategy for fabricating a nanoporous alkaline-exchange electrolyte membrane from natural cellulose nanofibres, exhibiting high ionic-conductivity and water retention as well as high bending flexibility. These advantages render the membrane a promising solid-state electrolyte for rechargeable zinc–air batteries in lightweight and flexible electronic applications.

A kinetic model for oxidative degradation of bagasse pulp fiber by sodium periodate.

In this paper, some key parameters, such as the system pH, the periodate concentration, and the reaction temperature, on the influence of the bagasse fiber degradation were studied based on the oxygenant of periodate. And the feasible reaction mechanism was also discussed through the FTIR characterization for bagasse fiber before and after the oxidizing reaction. As the results shown, the crystallinity of bagasse fiber decreased with the oxidation level increasing. It was interesting that the aldehyde content of the reaction system rose gradually along with cellulose degradation. Based on this result, the selective oxidation kinetics was constructed by introducing of variable factor R (the ratio of aldehyde content to the degradation of cellulose fiber), and the results shown that there was a better correlation between the dynamic model and the experimental data, so the oxidation degree of bagasse fiber oxidized by periodate can be quantitative evaluated based on this model.

Surface characterization and chemical analysis of bamboo substrates pretreated by alkali hydrogen peroxide.

The surface characterization and chemical analysis of bamboo substrates by alkali hydrogen peroxide pretreatment (AHPP) were investigated in this study. The results tended to manifest that AHPP prior to enzymatic and chemical treatment was potential for improving accessibility and reactivity of bamboo substrates. The inorganic components, organic solvent extractives and acid-soluble lignin were effectively removed by AHPP. X-ray photoelectron spectroscopy (XPS) analysis indicated that the surface of bamboo chips had less lignin but more carbohydrate after pre-treatment. Fiber surfaces became etched and collapsed, and more pores and debris on the substrate surface were observed with Scanning Electron Microscopy (SEM). Brenauer-Emmett-Teller (BET) results showed that both of pore volume and surface area were increased after AHPP. Although XRD analysis showed that AHPP led to relatively higher crystallinity, pre-extraction could overall enhance the accessibility of enzymes and chemicals into the bamboo structure.

Removal of hexenuronic acid by xylanase to reduce adsorbable organic halides formation in chlorine dioxide bleaching of bagasse pulp.

Xylanase-aided chlorine dioxide bleaching of bagasse pulp was investigated. The pulp was pretreated with xylanase and followed a chlorine dioxide bleaching stage. The ATR-FTIR and XPS were employed to determine the surface chemistry of the control pulp, xylanase treated and chlorine dioxide treated pulps. The hexenuronic acid (HexA) could obviously be reduced after xylanase pretreatment, and the adsorbable organic halides (AOX) were reduced after chlorine dioxide bleaching. Compared to the control pulp, AOX could be reduced by 21.4-26.6% with xylanase treatment. Chlorine dioxide demand could be reduced by 12.5-22% to achieve the same brightness. The ATR-FTIR and XPS results showed that lignin and hemicellulose (mainly HexA) were the main source for AOX formation. Xylanase pretreatment could remove HexA and expose more lignin, which decreased the chlorine dioxide demand and thus reduced formation of AOX.

Enzyme-assisted mechanical production of microfibrillated cellulose from Northern Bleached Softwood Kraft pulp

This paper examines the mechanism of an enzyme pre-treatment on mechanical preparation of microfibrillated cellulose (MFC), the effects of hemicellulase and cellulase, on enhancing of the PFI refining efficiency of Northern Bleached Softwood Kraft pulp for fiber’s devillicate, and changing of morphologies and physical characteristics on fibers, such as specific surface area were investigated, respectively. It was revealed that the enzyme pre-treatment could promote (1) an acceleration of fine productivity from the fibers, (2) intensive reduction of the size of the fibers through mechanical cutting and (or) fibrillation, and (3) energy efficiency in the reduction of fiber length without productivity impairment. However, distinct mechanical actions on the fibers pre-treated with hemicellulase and cellulase were indicated, according to the dissimilar fibrillation patterns and morphological properties found in the MFC product through intensive mechanical refining.

Acetylation improves thermal stability and transmittance in FOLED substrates based on nanocellulose films

Bleached softwood pulp was used to prepare nanofibrillated cellulose (NFC) by mechanical grinding and a high-pressure homogenization process. Acetylation improved the aspect ratio and dispersion of the NFC; however, highly acetylated NFC was not able to form a film by vacuum filtration if the NFC : acetic anhydride (AA) ratio was greater than 1 : 6. An NFC film prepared by acetylated NFC has potential as a flexible organic light-emitting device (FOLED) substrate. Acetylation improved the thermal stability and transmittance of NFC films, which were optimal at 5.43 ppm K−1 and 65%, respectively, when the ratio of NFC : AA was 1 : 3. Moreover, both the mechanical properties and flexibility of the NFC films were well maintained when the NFC : AA ratio was 1 : 3. Additionally, all NFC films prepared by acetylated NFC were smooth, flat, and uniform.

Transparent and Water-Resistant Composites Prepared from Acrylic Resins ABPE-10 and Acetylated Nanofibrillated Cellulose as Flexible Organic Light-Emitting Device Substrate

Acetylated nanofibrillated cellulose (ANFC)/acrylic resin ABPE-10 composite film was prepared by impregnating ABPE-10 into ANFC films under negative pressure, which can enhance properties of ANFC films by forming an interpenetrating polymer network structure between ABPE-10 and the ANFC film. The ANFC/ABPE-10 composite film met the high performance flexible organic light-emitting diode substrate requirement, even when the ANFC dosage was as high as approximately 70%. The transparency of films with different ANFC dosages significantly increased from 67% (42 µm) to 88% (45 µm), as determined by ultraviolet-visible analysis. The composite film inherited the properties of AFNC, with a low coefficient of thermal expansion and a ductile compact structure. The contact angles of ANFC films increased from 49.2° to 102.9° after dipping in ABPE-10. Additionally, the composite films had good surface smoothness and mechanical properties.

Effects of Pectinase Treatment on Pulping Properties and the Morphology and Structure of Bagasse Fiber

Bagasse was pretreated by pectinase, and both the control and pretreated bagasse were subjected to soda-anthraquinone (AQ) pulping. There were significant improvements in pulp properties after pectinase treatment, such as relative increases of brightness (5.5%), breaking length (17.1%), burst factor (16.5%), and tear factor (7.0%). The samples were analyzed by a fiber analyzer, scanning electron microscope (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The pectinase treatment changed the material properties, which would improve the efficiency of subsequent pulping, such as increasing the fiber length (20.0%), lowering the fines length (10.6%), and increasing the percentage of flexible fiber. Pectinase treatment removed some non-cellulose components; in particular, the pectin and alcohol-benzene extractives were decreased by 19.4% and 37.3% after enzymatic treatment. The hemicellulose and lignin were decreased by 5.5% and 1.9%, respectively. A bulkier and more collapsed fiber surface was observed in the treated fibers, which suggested greater pore volume and more accessible surface area. Treatment caused a slight incline by 4.8% in the crystallinity index. Some chemical structures in pectin, hemicellulose, and lignin were partly broken, showing the effect of pectinase treatment on the degradation of non-cellulose components. Pectinase treatment prior to pulping is therefore recommended, given its efficiency and eco-friendly nature.