Strong and optically transparent biocomposites reinforced with cellulose nanofibers isolated from peanut shell

Cellulose nanofibers–reinforced PVA biocomposites were prepared from peanut shell by chemical–mechanical treatments and impregnation method. The composite films were optically transparent and flexible, showed high mechanical and thermal properties. FE-SEM images showed that the isolated fibrous fragments had highly uniform diameters in the range of 15–50 nm and formed fine network structure, which is a guarantee of the transparency of biocomposites. Compared to that of pure PVA resin, the modulus and tensile strength of prepared nanocomposites increased from 0.6 GPa to 6.0 GPa and from 31 MPa to 125 MPa respectively with the fiber content as high as 80 wt%, while the light transmission of the composite only decreased 7% at a 600 nm wavelength. Furthermore, the composites exhibited excellent thermal properties with CTE as low as 19.1 ppm/K. These favorable properties indicated the high reinforcing efficiency of the cellulose nanofibers isolated from peanut shell in PVA composites.     

覆铜箔板纸的技术进展

介绍了覆铜箔板纸的用途,覆铜箔板的制造过程和应用.分析了覆铜箔板纸的性能与覆铜箔板性能的关系,总结了玻璃纤维覆铜箔板纸和纺纶纤维覆铜箔板纸的技术概况.提出了造纸行业要加强与其他行业的协作,在原料、制造工艺方面不断革新,开发出满足覆铜箔板行业发展需要的新产品.     

微胶囊制备技术及其在造纸工业中的应用

概述了应用于造纸印刷业制备微胶囊的主要技术和最新研究发展以及微胶囊技术在造纸方面的应用和应用前景。     

Highly porous graphitic materials prepared by catalytic graphitization

Ultrathin graphitic nanostructures are grown inside solid activated carbon particles by catalytic graphitization method with the aid of Ni. The graphitic nanostructures consist of 3–8 graphitic layers, forming a highly conductive network on the surface of disordered carbon frameworks. Owing to the ultrathin characteristic of the produced graphitic nanostructures, the resulted porous graphitic carbons show a high specific surface area up to 1622 m²/g. A detailed investigation reveals that the features of the growing graphitic nanostructures are strongly associated with the catalytic temperature as well as the state of Ni nanoparticles. Some well-dispersed fine Ni particles with diameter below 15 nm are found to be the key to form the ultrathin graphitic nanostructures at appropriate catalytic temperature. Also, a novel mechanism is proposed for the catalytic formation of the ultrathin graphitic nanostructures. As the electrode material of electrochemical capacitors, the porous graphitic carbon exhibits much higher high-rate capacitive performance compared to its activated carbon precursor.     

Evaluation of high throughput screening methods in picking up differences between cultivars of lignocellulosic biomass for ethanol production

We present a unique evaluation of three advanced high throughput pretreatment and enzymatic hydrolysis systems (HTPH-systems) for screening of lignocellulosic biomass for enzymatic saccharification. Straw from 20 cultivars of winter wheat from two sites in Denmark was hydrothermally pretreated and enzymatically processed in each of the separately engineered HTPH-systems at 1) University of California, Riverside, 2) National Renewable Energy Laboratory (NREL), Colorado, and 3) University of Copenhagen (CPH). All three systems were able to detect significant differences between the cultivars in the release of fermentable sugars, with average cellulose conversions of 57%, 64%, and 71% from Riverside, NREL and CPH, respectively. The best correlation of glucose yields was found between the Riverside and NREL systems (R² = 0.2139), and the best correlation for xylose yields was found between Riverside and CPH (R² = 0.4269). All three systems identified Flair as the highest yielding cultivar and Dinosor, Glasgow, and Robigus as low yielding cultivars. Despite different conditions in the three HTPH-systems, the approach of microscale screening for phenotypically less recalcitrant feedstock seems sufficiently robust to be used as a generic analytical platform.     

Natural Rosin-based Phosphate Diester Surfactant Assisted One-step Synthesis of 3D Flowerlike β-Ni(OH)2/g-Ni(OH)2 Composite Nano-microspheres

Self-assembled uniform 3D flowerlikeβ-Ni(OH)₂/g-Ni(OH)₂ composite nano-microspheres with hollow interiors were successfully synthesized via a facile aqueous-ethanol mixed solvothermal method, using nickel sulfate as a precursor, urea as a precipitant, and dehydroabietic based phosphate diester sodium (DDPDS) as a surfactant. The prepared 3D flowerlikeβ-Ni(OH)₂/g-Ni(OH)₂ composite nano-microspheres were tested as supercapacitors in a two-electrode cell with 6 mol/L KOH electrolyte. In addition, the influence of DDPDS concentration on the morphology and size of 3D flowerlikeβ-Ni(OH)₂/g-Ni(OH)₂ composite nano-microspheres was studied at 180℃. X-ray diffraction (XRD), scanning electron microscopy (SEM), BET (Brunauer, Emmett and Teller) techniques, and equity default swap (EDS) were used to characterize the structure, morphology, and size of the as-prepared samples. Moreover, a possible formation mechanism of the 3D flowerlikeβ-Ni(OH)₂/g-Ni(OH)₂composite nano-microspheres was proposed based on the effects of DDPDS concentration and reaction time. The surfactant micelles were used as soft templates to induce the self-assembly of nanosheets. The crystallinity of the 3D flowerlikeβ-Ni(OH)₂/g-Ni(OH)₂ composite nano-microspheres improved with the increase of DDPDS concentration, and the morphology and size of synthetic nano-microspheres could be controlled.     

Conductive Polyaniline/Cellulose/Graphite Composite Films with High Thermal Stability and Antibacterial Activity

Functional composite films were successfully prepared from cellulose, graphite (GP), and polyaniline (PANI) using a combination of physical and chemical processes. Cellulose was dissolved in N-methylmorpholine-N-oxide monohydrate (NMMO) and regenerated in water to form the matrix. GP was dispersed in the NMMO solvent prior to the dissolution of the cellulose, and PANI was deposited on the surfaces of the cellulose/GP films by in situ chemical polymerization. The structures of the PANI/cellusose/GP composite films were investigated using X-ray diffraction analysis, Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), and SEM/energy-dispersive X-ray spectroscopy. The mechanical strengths, thermal stabilities, conductivities, and antibacterial activities of the films were studied in detail. The results showed that GP formed a multilayered structure in the cellulose matrix and that the PANI nanoparticles were tightly wrapped on the film surface. The film thickness increased from 40 m to 100 m after the addition of GP and PANI. The tensile strength of the composite films was 80~107 MPa, with the elongation at break being 3%~10%. The final residual weight of the composite films was as high as 65%, and the conductivity of the composite films reached 14.36 S/m. The cellulose matrix ensured that the films were flexible and exhibited desirable mechanical properties, while the GP filler significantly improved the thermal stability of the films. The PANI coating acted as a protective layer during burning and provided good electrical conductivity and antibacterial activity against Escherichia coli; both of these characteristics were slightly enhanced by the incorporation of GP. These PANI/cellulose/GP composite films should be suitable for use in electronics, antistatic packing, and numerous other applications.     

Comparison of cellulose and chitin nanocrystals for reinforcing regenerated cellulose fibers

In this study, regenerated cellulose fibers reinforced by cellulose nanocrystals (CENC) and chitin nanocrystals (CHNC) were prepared by blending the nanocrystals suspensions with the cellulose solution in NaOH/urea/water solvent at room temperature. The effect of nanocrystals' addition on the properties of spinning dopes and regenerated fibers were investigated and compared. Results showed that the obtained CENC and CHNC had different dimensions, and both of them increased the viscosity and decreased the transparency of the spinning dopes. However, the dissolution state of cellulose was not changed. CHNC had a greater influence on the properties of spinning dopes, while CENC had more obvious effect on the performance of regenerated fibers. The CENC reinforced fibers showed a higher crystallinity index as compared to the CHNC reinforced fibers. The tensile strength of the regenerated fibers was evidently improved when 3 wt % CENC or 2 wt % CHNC were added, while the elongation at break of the fibers was slightly decreased with the increase of nanocrystals content. The morphology and thermal stability of the regenerated fibers was not affected by the addition of nanocrystals. This study suggested that the dimension, group and content of nanocrystals were important factors for the reinforcement of regenerated cellulose fibers. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44880.     

In situ grown Cu-Based metal-organic framework on copper foam as high-performance electrocatalysts for oxygen evolution reaction

It is of great significance to develop highly efficient and robust oxygen evolution reaction (OER) electrocatalysts derived from earth-abundant and inexpensive elements for future hydrogen economy via electrochemical water splitting. Herein, Cu-based metal-organic framework (MOF) is directly supported on conductive Cu foam (CF) by a simply chemical oxidation of Cu substrate to grow Cu(OH)₂ nanowire arrays, followed by solvothermal treatment to obtain in situ grown Cu-based MOF electrode (MOF [Cu(OH)₂]/CF). The as-prepared 3D electrode shows superior OER activity with a low potential of 330 mV to deliver a current density of 10 mA cm⁻², a Tafel slope of 108 mV dec⁻¹, and excellent durability in alkaline media (1.0 M KOH). After electrolysis, XRD confirms that the initial MOFs have been transformed into CuO species, which are essentially active components for OER performance. This demonstrates that the MOFs can serve as efficient precursors for formation of highly active Cu oxide catalysts towards OER. This work provides a new strategy to develop MOFs-derived electrocatalysts for future clean energy conversion and storage systems.