No abstract

Polyetherimide (PEI) is a kind of high-performance polymer, which possesses a high glass transition temperature ( Tg), excellent flame retardancy, low smoke generation, and good mechanical properties. In this article, PEI was applied in the fused deposition modeling (FDM)–based 3-D printing for the first time. The entire process from filament extrusion to printing was studied. It was observed that the filament orientation and nozzle temperature were closely related to the mechanical properties of printed samples. When the nozzle temperature is 370°C, the mean tensile strength of FDM printing parts can reach to 104 MPa, which is only 7% lower than that of injection molded parts. It can be seen that the 0° orientation set of samples show the highest storage modulus (2492 MPa) followed by the 45° samples, and the 90° orientation set of samples show the minimum storage modulus (1420 MPa) at room temperature. The above results indicated that this technique allows the production of parts with adequate mechanical performance, which does not need to be restricted to the production of mock-ups and prototypes. Our work broke the limitations of traditional FDM technology and expanded the types of material available for FDM to the high-temperature engineering plastics.

Micro- and nanopatterning of cost-effective addressable metallic nanostructures has been a long endeavor in terms of both scientific understanding and industrial needs. Herein, a simple and efficient dynamic meniscus-confined electrodeposition (MCED) technique for precisely positioned copper line micropatterns with superior electrical conductivity (greater than 1.57 × 10 S/cm) on glass, silicon, and gold substrates is reported. An unexpected higher printing speed in the evaporative regime is realized for precisely positioned copper lines patterns with uniform width and height under horizontal scanning-mode. The final line height and width depend on the typical behavior of traditional flow coating process, while the surface morphologies and roughness are mainly governed by evaporation-driven electrocrystallization dynamics near the receding moving contact line. Integrated 3D structures and a rapid prototyping of 3D hot-wire anemometer are further demonstrated, which is very important for the freedom integration applications in advanced conceptual devices, such as miniaturized electronics and biomedical sensors and actuators.

Abstract:In this study, phosphorylated birchwood xylan was produced under alkali conditions using trisodium trimetaphosphate. Three single-factor experiments were used to explore the influences of time, temperature, and the molar ratio of trisodium trimetaphosphate to xylan on the degree of substitution (DS) and charge density of xylan. The response surface methodology was used to explore the interaction of these three factors. Phosphorylated xylan with a maximum DS of 0.79 and a charge density of −3.40 mmol/g was produced under the optimal conditions of 80 • C, 4 h, and a molar ratio of xylan/sodium trimetaphosphate (STMP) of 1/3. Fourier transform infrared (FTIR), ascorbic acid method analyses, and inductively coupled plasma-atomic emission spectrometer (ICP-AES) analyses confirmed that the phosphate groups were successfully attached to xylan. Thermogravimetric analysis confirmed that phosphorylated xylan was less stable than birchwood xylan. Furthermore, the phosphorylated xylan was applied as a flocculant for removing ethyl violet dye from a simulated dye solution. The results indicated that more than 95% of the dye was removed from the solution. The theoretical and experimental values of charge neutralization for the dye removal were close to one another, confirming that charge neutralization was the main mechanism for the interaction of dye and phosphorylated xylan. The impacts of salts on the flocculation efficiency of phosphorylated xylan were also analyzed.

No abstract

No abstract

Softwood kraft lignin is a renewable type of woody material that can be converted to value-added products, for example, as a paper strength additive in the paper industry. In this study, the monomers of methacryloxyethyltrimethyl ammonium chloride (DMC), acrylic acid (AA), and acrylamide (AM) were grafted on softwood kraft lignin (SKL) to prepare three different SKL copolymers. Fourier-transform infrared, proton nuclear magnetic resonance, charge density, elemental, and molecular weight analyses confirmed that the monomers were successfully grafted onto SKL. The grafting rates of SKL-DMC, SKL-AA, and SKL-AM copolymers were 80.35%, 82.70%, and 79.48%, respectively. The application of SKL copolymers as a paper additive for enhancing paper physical properties was studied. The results indicated that at a 2 wt % dosage of SKL copolymers, the increase in the physical properties of paper is maximum.

The main purpose of this study is to explore the sulfation of xylan to produce an anionic flocculant, sulfated xylan, for removing ethyl violet dye from simulated dye solutions. In this work, xylan was sulfated with chlorosulfonic acid in N, N-dimethylformamide solvent and the reaction conditions were optimized using a response surface methodology. It was observed that the maximum degree of substitution of 1.1 was obtained for sulfated xylan under the conditions of 3.71 chlorosulfonic acid/xylan molar ratio, 70°C and 7 h reaction time. The resulting sulfated xylan had a charge density of -3.12 mmol/g and molecular weight (M ) of 22,300 g/mol. Furthermore, elemental and thermogravimetric analyses, Fourier transform infrared spectroscopy and proton nuclear magnetic resonance ( H-NMR) confirmed the sulfation of xylan. The application of sulfated xylan as a flocculant for decolorizing the simulated ethyl violet dye wastewater was studied. The results indicated that 97% of dye was removed from 50 mg/L dye solution at the sulfated concentration of 175 mg/L and pH 9, but unmodified xylan was ineffective in flocculating and removing dye segments. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:529-536, 2018.