Jicheng Xu

Adsorption Behavior of Azo Dye Eriochrome Black T from Aqueous Solution by β-Cyclodextrins/Polyurethane Foam Material

β-cyclodextrin/polyurethane (β-CD/PU) materials were prepared by foaming technique. The adsorption behavior of EBT on β-CD/PU material and the influences on the adsorption efficiency were investigated. Under the optimal experimental conditions, the maximum adsorption efficiency of EBT was 93.14%. The kinetics characteristic and thermodynamic parameters were analyzed. The experimental isotherms data were analyzed using Langmuir and Freundlich isotherm equations and the results indicated that the Langmuir isotherm showed a better fit for EBT adsorption. The experimental results suggest that the β-CD/PU foam materials have potential application for the wastewater treatment containing EBT dye.

Preparation, characterization and properties of UV-curable waterborne polyurethane acrylate/SiO2 coating

The UV-curable waterborne polyurethane acrylate (UV-WPUA) oligomer was first prepared based on isophorone diisocyanate (IPDI), polyether polyol (NJ-220), dimethylol propionic acid (DMPA), and hydroxyethyl methyl acrylate (HEMA) via an in situ method. With the different content tetraethoxysilane (TEOS) and 3-glycidyloxypropyltrimethoxysilane (GLYMO) as coupling agents, a series of waterborne UV-WPUA/SiO2 oligomers were prepared by the sol–gel process. The physical and mechanical properties of the UV-WPUA and UV-WPUA/SiO2 hybrid coating materials were measured. The UV-WPUA and WPUA/SiO2 hybrid materials were characterized using FTIR spectra, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscope (SEM), transmission electron microscope (TEM), and X-ray diffraction (XRD) measuring apparatuses to determine their structures, thermal properties, surface morphologies, etc. The results showed the SiO2 particles of the hybrid materials had wide dispersion, forming a good interfacial bonding layer on surfaces. The tensile strength, water resistance, and thermal properties of the hybrid materials were better than those of the UV-WPUA. The resulting UV-WPUA/SiO2 hybrids are promising for a number of applications, e.g., for high-performance water-based UV-curable coatings.

Preparation, Characterization and Dye Decolorization Application of Chitosan/Polyurethane Foam Material

A series of chitosan/polyurethane (Cs/PU) materials were prepared from polyether polyol, isophorone diisocyanate, chitosan, n-hexane as foaming agent, dibutylbis (lauroyloxy) tin as catalyst and silicon oil as stabilizer by foaming technique. The materials were characterized by FT-IR, DSC and TGA. Cs/PU materials were used to decolorize azo dye. Decolorizing process was spontaneous at ambient temperature and presented an exothermic characteristic. The decolorization experiments were carried out and around 78% of the azo present in solution could be removed. The experimental results suggest that the Cs/PU materials have potential applications as decolorizing agent for the treatment of dye effluents.

Fabrication of fluorescent carbon dots-linked isophorone diisocyanate and β-cyclodextrin for detection of chromium ions

A water-soluble fluorescent carbon dots (FCDs) from cellulose was prepared using one-pot simple hydrothermal method. In this work, a novel fluorescent probe material, fluorescent carbon dots-linked isophorone diisocyanate and β-cyclodextrin (FCDs-IPDI-CD), was prepared with FCDs, isophorone diisocyanate (IPDI) and β-cyclodextrin (β-CD) as raw materials. The structure and morphology of FCDs-IPDI-CD were characterized using the Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). The as-prepared FCDs-IPDI-CD exhibits excellent emission property and high stability. The fluorescence of the FCDs-IPDI-CD could be quenched by Cr(VI) ions, and the results indicate that FCDs-IPDI-CD can be used as an effective fluorescent probe for the detection of Cr(VI) ions with good selectivity and sensitivity in an aqueous solution. The influences of environment factors (such as pH, reaction time) on relative fluorescence intensity were studied. According to the optimum conditions, a new sensitive method detecting Cr(VI) ions was established. The method has been successfully applied to detect Cr(VI) ions in water and soil samples with satisfactory results.

Preparation and Properties of Graphene Oxide-Modified Waterborne Polyurethane-Acrylate Hybrids

A series of graphene oxide-modified waterborne polyurethane-acrylate (GEO/WPUA) hybrids were prepared and characterized by FT-IR, SEM, TEM and XRD. The result shows that graphene oxide in the hybrid has good dispersion. The mechanical property, thermal stability and water resistance of hybrids with different content of GEO were investigated. The results indicate that GEO/WPUA films have bigger tensile strength and hardness than pure WPUA. When the content of GEO is 0.015%, the hybrid has the best water resistance. The obtained GEO/WPUA hybrids have great potential application such as coatings, leather finishing, adhesives, sealants, plastic coatings and wood finishes.

A novel water-soluble chitosan linked fluorescent carbon dots and isophorone diisocyanate fluorescent material toward detection of chromium(VI)

In this work, a NCO-capped intermediate was first prepared from fluorescent carbon dots (FCDs) and isophorone diisocyanate (IPDI) via an in situ method in the presence of dibutyltin dilaurate as the catalyst. Based on the fact that –NCO groups can react with the hydroxyl and amino groups in chitosan polymeric chains, a novel water-soluble chitosan linked fluorescent carbon dots and isophorone diisocyanate (FCDs–IPDI–CTS) fluorescent material was obtained from the NCO-capped intermediate and chitosan. The prepared FCDs–IPDI–CTS material shows blue fluorescence under UV exposure. The structure and morphology of the as-prepared FCDs–IPDI–CTS material were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The as-prepared FCDs–IPDI–CTS material exhibits excellent fluorescence properties and good stability. It could be quenched by chromium(VI) and has been further used as a novel fluorescent probe for selective detection of chromium(VI). The optimum conditions for sensing Cr(VI) were investigated. Based on the optimum conditions, a new sensitive method for sensing Cr(VI) was established. This method has been successfully applied to detect Cr(VI) in water and soil samples with satisfactory results.

Preparation and artificial ageing tests in stone conservation of fluorosilicone vinyl acetate/acrylic/epoxy polymers

In this work, a series of fluorosilicone vinyl acetate/acrylic/epoxy (FVAE) polymers for protection of stone relics were prepared with different content of hexafluorobutyl methacrylate (HFBMA) by the seed emulsion polymerization process. Properties and structure of FVAE materials were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG), and transmission electron microscopy (TEM). Viscosity, particle size, surface tension, gel content, adhesion and surface hardness of polymer materials were also determined. Surface morphology of the stone sample was observed by scanning electron microscopy (SEM). Compared with a commercial copolymer, ethyl methacrylate/methyl acrylate (EM/MA, Paraloid B72), protection ability of the prepared FVAE polymer was investigated using artificial ageing tests such as the freeze-thaw aging test, acid aging test and the soluble salts aging test. It was found that the FVAE polymers prepared can effectively prevent corrosion caused by H+, formation of an interface crack and further weathering, which indicates their possible application in stone protection.

Synthesis, mechanical properties and iron surface conservation behavior of UV-curable waterborne polyurethane-acrylate coating modified with inorganic carbonate

The performances of UV-curable waterborne polyurethane-acrylate (WPUA) composite modified with nano calcium carbonate (NCA) were highlighted in this work. The γ-methacryloxy propyl trimethoxyl silane (KH-570) and polysorbate 80 (Tween-80) were used to enhance interfacial interaction between NCA and WPUA matrix. Transmission electron microscopy (TEM), particle size analysis and Fourier transfer infrared (FT-IR) spectrometry were employed to examine the micromorphology and the variation of function group of modified nano calcium carbonate (MNCA). Three different WPUA oligomers were investigated to obtain the optimized R value (the molar ratio of –NCO:–OH) via in situ polymerization and anion self-emulsification process. Results showed that WPUA displayed excellent film-forming ability and mechanical properties when R value was 2.2:1.0. These UV-curable WPUA films modified with MNCA (UV-MNCA/WPUA) were prepared through environmentally friendly UV-curable technology and investigated by thermogravimetric (TG) analysis, scanning electron microscope (SEM), X-ray diffractometer (XRD) and FT-IR. UV-MNCA/WPUA-3-3 film had the best overall performances with MNCA-2 and UV-WPUA at the mass ratio of 3.6%. Finally, the experimental results demonstrated that the as-obtained UV-curable coating had outstanding conservation effect to iron surface, providing a promising way for protection of iron cultural relics.

Preparation and application of modified carboxymethyl cellulose Si/polyacrylate protective coating material for paper relics

There are large numbers of paper cultural relics in China, the country where paper making was invented. However, the paper relics have not been adequately protected so they are at risk of ageing, damage and disappearance. In order to better protect the paper relics, modified carboxymethyl cellulose/Si/polyacrylate protective materials were prepared with acrylicresin and modified carboxymethyl cellulose which has a good affinity with the paper and modified silica, improving the mechanical strength and ability to withstand weathering. The modified CMC/Si/polyacrylate protective material was analysed using infrared spectroscopy, transmission electron microscopy, differential scanning calorimetry and other performance-testing devices. The surface morphology of the paper samples was analysed using scanning electron microscopy. The protective material so prepared was evaluated by subjection to accelerated ageing (dry heat treatment). The results showed the protective material films to have good hydrophobicity, acid/alkali resistance and mechanical strength. When the content of SiO2 is 6 mass %, the protective material has an excellent comprehensive performance. The results of the ageing test reveal that the prepared material can effectively slow down the ageing rate. The prepared material is suited to the protection of paper cultural relics.

Controlled and facile synthesis of a self-assembled enzyme–inorganic catalyst based on flexible metal-coated fiber for an excellent removal of synthetic pollutants from aqueous environment

The development of green sustainable chemistry opens the door to the application of biocatalytic in numerous fields for the research in industry and academia. As a common biological catalyst, enzyme catalysis is ideally suited and widely applicable for various desired reaction. In this work, a hierarchical structure laccase–Cu3(PO4)2·3H2O nanoflower-coated silica fiber (La–CNSF) was successfully fabricated with hundreds of Cu3(PO4)2 nanosheets formed on the processed silica fibers as the petal and laccase as the enzyme catalyst. It included two processes: first, Cu nanoparticles were directly grown on silica fiber cloth as a precursor and three-dimensional (3D) Cu3(PO4)2·3H2O nanoflower was self-assembled on Cu-coated fibers by post-processing. Then, La–CNSF was successfully immobilized via a simple one-step immersion reaction in a laccase-phosphate buffer solution (PBS) solution. The product was characterized by FTIR, XRD, SEM and UV–visible spectroscopy. Congo red was realized using La–CNSF as a biocatalyst. Compared with pure laccase, La–CNSF sample exhibits an enhanced catalytic activity. The flower-like structure assembled on the fiber provided La–CNSF high storage stability and reusability in contrast with free laccase. The superior catalytic performance of La–CNSF supports a potential strategy for purification of water pollutants, and it favors the realization of the engineering of large scale applications of enzyme catalysis.