Immobilization of enzyme could offer the biocatalyst with increased stability and important recoverability, which plays a vital role in the enzyme's industrial applications. In this study, we present a new strategy to build an intelligent enzyme carrier by coating titania nanoparticles with thermoresponsive epoxy-functionalized polymers. Zero-valent copper-mediated living radical polymerization (Cu(0)-LRP) was utilized herein to copolymerize N-isopropylacrylamide (NIPAM) and glycidyl acrylate (GA) directly from an unprotected dopamine-functionalized initiator to obtain an epoxy-containing polymer with terminal anchor for the "grafting to" or "one-pot" modification of titania nanoparticles. A rhodamine B-labeled laccase has been subsequently used as a model enzyme for successful immobilization to yield an intelligent titania/laccase hybrid bifunctional catalyst. The immobilized laccase has shown excellent thermal stability under ambient or even relatively high temperature above the lower critical solution temperature (LCST) at which temperature the hybrid particles could be facilely recovered for reuse. The enzyme activity could be maintained during the repeated use after recovery and enzymatic degradation of bisphenol A was proven to be efficient. The photocatalytic ability of titania was also investigated by fast degradation of rhodamine B under the excitation of simulated sunlight. Therefore, this study has provided a facile strategy for the immobilization of metal oxide catalysts with enzymes, which constructs a novel bifunctional catalyst that will be promising for the "one-pot" degradation of different organic pollutants.
An environment-dependent tight-binding potential model for copper within the framework of quantum theory is developed. Our benchmark calculations indicate that this model has good performance in describing the elastic property, the stability and the vibrational property of bulk copper, as well as in handling the clusters, the surfaces and the defective Cu systems. By combining this model with molecular dynamics, we study how the evolution of structural defects arising from the irradiation of the energetic particles influences the mechanical and the thermal properties of the copper-heat-sinks in fusion reactors. Based on our simulations, the heat blockade in the irradiated Cuheat-sinks is predicted. This finding is valuable for the development of wall materials in fusion reactors.
Due to high flammability setback of most natural and synthetic rubbers, a novel organic/ inorganic hybrid flame-retardant additive by the combination of tricresyl phosphate (TCP) and organomontmorillonite (OMMT) was prepared and used in the preparation of flame-retardant rubber composites. Different types of natural rubber (NR)/TCP/ OMMT composites were prepared with different amounts of this novel additive. Then, the main properties were researched and compared with the composites directly incorporated with TCP or OMMT. The tensile strength and elongation at break of NR/TCP-10/OMMT-5 were 15.5 MPa and 673%, respectively, which increased about 10% and 16% compared with that of NR/TCP-10 composite. Meanwhile, the abrasion loss of NR/TCP-10/OMMT-5 was 0.49 cm 3 , decreased by 26% in comparison with that of NR/OMMT-5 composite, that is, to 0.62 cm 3 . Moreover, the limiting oxygen index value was increased to about 34.0% and the thermal stability of which was also improved with the addition of 10 parts per hundreds of rubber of TCP and OMMT into NR systems. In addition, the plausible mechanism for the improvement of reinforcing, wear resistant, and flameretardant properties were put forward.
Novel methyl vinyl silicone rubber (MVQ)/calcium sulfate whisker (CSW) composites had been prepared. Two types of modification agents, hydrogen silicone oil and silane coupling agent, were used in the preparation of modified calcium sulfate whiskers (MCSW). The morphology and properties of MCSW were analyzed by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). Then, the two types of MCSW were applied in the preparation of MVQ composites. Properties such as cure characteristics, tensile strength, elongation at break, permanent distortion and thermal stability were analysed and compared. Results showed that addition of MCSW could improve the tensile and thermal properties of the silicone rubber composites. A combination of SEM studies was used to characterize the structure and reinforcing mechanism of MCSW.
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