Pyrolytic preparation and modification of carbon black recovered from waste tyres.

The medium temperature pyrolysis process using a fixed-bed reactor at atmospheric pressure was utilised to recover carbon black from motorcycle and automobile tyres. Experimental results have shown that the ash and volatile contents of several recovered carbon blacks are high, the elongation at break of the vulcanised natural rubber filled with recovered carbon blacks from motorcycle tyres is better than that from motorcycle tyres and standard carbon black 7#, while the other mechanical properties are worse. In order to improve the reinforcing effect of recovered carbon blacks, the modification of recovered carbon black was performed by high-energy electron bombardment and non-oxidising acid. The specific surface area of the pyrolytic carbon blacks increased after high-energy electron bombardment. The ash content of the pyrolytic carbon black was reduced from 22.5% to 8.4% after rinsing with hydrochloric acid, and the tensile stress at 300% was increased by about 2.2 MPa.

Polyacrylic acid and ß-cyclodextrin polymer cross-linking binders to enhance capacity performance of silicon/carbon composite electrodes in lithium-ion batteries.

Binders play a key role in maintaining the integrity of high-capacity silicon anodes, which otherwise experience serious capacity decay during cycling caused by huge volume variation of the silicon. With an aim to developing a highly efficient polymeric binder to mitigate this capacity decay, we present a novel binder synthesized from polyacrylic acid (PAA) and polymerized ß-cyclodextrin (ß-CDp) for Si anodes for the lithium-ion batteries. This PAA-ß-CDp binder has a 3D network structure, which provides strong adhesion between the active material and the current collector. PAA-ß-CDp binder makes silicon anode achieve a specific capacity of 2326.4 mAhg-1 at the current density of 0.2 A g-1 with a capacity retention of 64.6% after 100 cycles. The experimental results show that the PAA-ß-CDp binder can effectively mitigate the huge volume change and improve the capacity and cycling performance of Si anodes.

Preparation and Characterization of Graphene Oxide/Polyaniline/Polydopamine Nanocomposites towards Long-Term Anticorrosive Performance of Epoxy Coatings.

To address the challenging issues of metal materials corrosion in industries, which has caused huge economic losses and security threats to many facilities in marine environments, functional polymer coatings have been widely used and regarded as one of the simplest and most effective methods to prevent such an undesirable event. In this study, a new type of coating filler consisting of graphene oxide/polyaniline/polydopamine (GO-PANI-PDA) nanocomposites has been successfully synthesized. The morphology, structure, composition, and corrosion resistance performance of the GO-PANI-PDA (GPP) nanocomposites were investigated via a series of characterization methods. The results from our electrochemical impedance spectroscopy, potentiodynamic polarization curve and salt spray experiment showed that the best corrosion resistance performance of the coating is from GPP 21 with the epoxy/GO-PANI:PDA ratio of 2:1, which exhibited a positive corrosion potential (-0.51 V) shift from epoxy/GO-PANI coating (-0.64 V). The corrosion current density (3.83 × 10-8 A/cm2) of GPP 21 is nearly an order of magnitude lower than that of epoxy/GO-PANI (7.05 × 10-7 A/cm2). The good anti-corrosion performance was fascinatingly observed in salt spray tests even without obvious corrosion phenomenon after 30 days of testing. Due to these remarkable properties, GPP nanocomposites can be an outstanding candidate for the rapid development of broadband shielding and anticorrosive materials.

Continuous preparation of a nontoxic magnetic fluid as a dual-mode contrast agent for MRI.

Ultrasmall nanoparticle contrast agents provide dual-mode MRI. However, the application of ultrasmall nanoparticle contrast agents is limited by low manufacturing outputs and cumbersome preparation processes. Herein, we report a novel continuous-flow coprecipitation method for the preparation of the Fe3O4 nanoparticles magnetic fluid (CFCPFe) coated with ultrasmall cysteine-terminated polymethacrylic acid (Cys-PMAA). The preparation process is more coherent, simpler, and less expensive. Compared with magnetic fluids prepared by the conventional method (Cys-PMAA@Fe3O4), CFCPFe has smaller particle sizes (3.27 ± 0.93 nm). Moreover, CFCPFe demonstrates excellent stability for >180 days with different pH values (pH = 2-12) and salt concentrations (up to 2 mol/L). In addition, HEK293T cytotoxicity tests, hemolysis tests, and H&E tissue sections show excellent in vitro and in vivo biocompatibility. In vitro magnetic resonance imaging (MRI) at 1.5 T shows that the r2 value (50.51 mM-1·s-1) of CFCPFe is slightly lower than that of Combidex (r2 = 65 mM-1·s-1) and that the r1 value (9.54 mM-1·s-1) is 2.7 times higher than that of Gd-DTPA (r1 = 3.5 mM-1·s-1). Finally, in vivo imaging shows that CFCPFe reaches the tumor region of the mouse liver cancer model, and a small tumor can be observed in dual-mode imaging. This work offers an effective method for the preparation of a low-cost, stable, and biocompatible ultrasmall contrast agent exhibiting a strong magnetic-imaging effect for dual-mode imaging.

Preparation and characterization of chitosan poly(acrylic acid) magnetic microspheres.

Spherical microparticles, capable of responding to magnetic fields, were prepared by encapsulating dextran-coated Fe3O4 nanoparticles into chitosan poly(acrylic acid) (PAA) microspheres template. The obtained magnetic microspheres were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray powder diffraction (XRD), and thermogravimetry (TG). The results showed that the microspheres were formed and demonstrated magnetic behavior in an applied magnetic field. In addition, magnetite particles were well encapsulated and the composite particles have high magnetite content, which was more than 40%.

Enhanced activity towards polyacrylates and poly(vinyl acetate) by site-directed mutagenesis of Humicola insolens cutinase.

Previous studies on the hydrolysis of polyacrylates by cutinase have found that cutinase from Humicola insolens can fulfill the requirement for a thermostable cutinase in the treatment of stickies from papermaking, but it has poor hydrolysis ability. To further improve its ability to hydrolyze the polymers in papermaking, we analyzed the structure of cutinase from H. insolens, and constructed three mutants L66A, I169A, and L66A/I169A to reduce the steric hindrance of the substrate binding region. The hydrolysis results for poly(methyl acrylate), poly(ethyl acrylate), and poly(vinyl acetate) showed the catalytic ability of the mutant L66A/I169A most significantly improved. Using polymer macroporous resin composites as substrate, the released products of L66A/I169A were 1.3-4.4 times higher than that of the wild-type enzyme. When polymer suspensions were no longer being deposited, that is, when the turbidity decrease was less than 1%, the amount of L66A/I169A added was reduced by 19%-51% compared with that of the wild-type enzyme. These results indicated that the removal of the gatekeeper structure above the substrate binding region of H. insolens cutinase enhances its ability to hydrolyze polymers, and provided a basis for the application of cutinase in the practical treatment of stickies.

Plasma Exfoliated Graphene: Preparation via Rapid, Mild Thermal Reduction of Graphene Oxide and Application in Lithium Batteries.

A simple, novel approach is proposed for the preparation of plasma-exfoliated graphene (PEGN) by reducing graphene oxide (GO) through a dielectric-barrier discharge (DBD) plasma treatment in a H2 atmosphere. The surface chemistry, microstructures, and crystallinity of the prepared samples were characterized via X-ray photoelectron spectroscopy, transmission electron microscopy, and Raman spectrometry to determine the formation mechanism of the PEGN. The results demonstrated that the prepared PEGN had only a few layers in its structure and that most of the functional groups containing oxygen on the GO surface were removed. The PEGN exhibited a considerably higher capacity, better cycling stability, and favorable electron transfer rate for use as a cathode material for lithium-ion batteries. This proposed approach is fast, convenient, and inexpensive, constituting a novel means of producing graphene.

High-level expression of Humicola insolens cutinase in Pichia pastoris without carbon starvation and its use in cotton fabric bioscouring.

Huimcola insolens cutinase (HiC) was heterologously expressed in Pichia pastoris. To avoid a carbon starvation step, fermentation was conducted using combinations of sorbitol with glycerol and methanol in the cell growth and induction phases, respectively. The cutinase productivity (27.71 U mL-1 h-1) was 9.93 U mL-1 h-1 greater than that achieved using traditional two-phase methods, and a cutinase activity of 2660 U mL-1, using p-nitrophenyl butyrate as substrate, was achieved after only 96 h in a 3-L bioreactor. Subsequently, the combination of HiC with Thermobifida fusca cutinase (TfC) in cotton fabric bioscouring was evaluated by monitoring the wettability and dyeability of the fabric. Treatment with 20 U mL-1 of HiC at 80 °C for 5 min followed by 30 U mL-1 of TfC at 50 °C for 1 h gave the best results. The total treatment time was shorter and performance was better than those seen with the alkali method.

Short-chain aliphatic ester synthesis using Thermobifida fusca cutinase.

Short-chain aliphatic esters are commonly used as fruit flavorings in the food industry. In this study, Thermobifida fusca (T. fusca) cutinase was used for the synthesis of aliphatic esters, and the maximum yield of ethyl caproate reached 99.2% at a cutinase concentration of 50U/ml, 40°C, and water content of 0.5%, representing the highest ester yield to date. The cutinase-catalyzed esterification displayed strong tolerance for water content (up to 8%) and acid concentration (up to 0.8M). At substrate concentrations ⩽0.8M, the ester yield remained above 80%. Moreover, ester yields of more than 98% and 95% were achieved for acids of C3-C8 and alcohols of C1-C6, respectively, indicating extensive chain length selectivity of the cutinase. These results demonstrate the superior ability of T. fusca cutinase to catalyze the synthesis of short-chain esters. This study provides the basis for industrial production of short-chain esters using T. fusca cutinase.

Influence of manure types and pyrolysis conditions on the oxidation behavior of manure char.

Livestock manure can be quickly converted into valuable products (H(2), syn-gas and char) by low temperature gasification. Manure char combustion offers energy for the gasification reactions. In the paper, the influence of manure type and pyrolysis conditions on manure char reactivity is addressed. The results show that the oxidation behaviors of manure char are dependent strongly on manure type and pyrolysis conditions employed. The large difference between the oxidation behaviors of pig and hen manure chars can be attributed to the difference in the organic materials and minerals of the samples. High final temperature, flash pyrolysis and water steam atmosphere used for char preparation promote the resultant char reactivity.