Yuting Dai

UV-curable electromagnetic shielding composite films produced through waterborne polyurethane-acrylate bonded graphene oxide: preparation and effect of different diluents on the properties

Abstract UV-curable electromagnetic shielding composite films (UV-EMSF) were prepared with graphene oxide/polyurethane-acrylate (GO-PUA) oligomers, different diluents (styrene-butyl acrylate or tripropyleneglycol diacrylate-butyl acrylate or trimethylol propane triacrylate-butyl acrylate) and photoinitiator (2-hydroxy-2-methyl-1-phenyl-1-propanone). The chemical structures, morphology, crystallinity and thermal behavior of UV-EMSF were investigated by Fourier transform-infrared spectroscopy, scanning electron microscope, X-ray diffraction and thermogravimetric analysis. The stability, optical transparency and electrical conductivity of emulsions were measured. The effects of different diluents on the properties such as gel content, solvent resistance, hardness, tensile strength, contact angle and adhesion force were systemically studied. It was found that the emulsions had a good stability and the electrical conductivity of the emulsions indicated that the addition of GO had an effect on the electric conductivity. The prepared UV-EMSF composites with low-cost, low pollution and easy-to-prepare low resistivity have a great potential application in different areas such as electronic, electrical, communications, plastic coatings and wood finishes.

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.

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.

Fabrication of UV-curable waterborne fluorinated polyurethane-acrylate and its application for simulated iron cultural relic protection

In this study, UV-curable waterborne fluorinated polyurethane-acrylate (UV-WFPUA) coatings were investigated to evaluate their potential application for protecting iron cultural relics. A series of UV-WFPUA materials were synthesized with different contents of hexafluorobutyl methacrylate (HFBMA) and characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. When the content of HFBMA was 10%, the UV-WFPUA-3 material exhibited good mechanical properties and excellent hydrophobicity. The iron sheet was selected to simulate an iron artifact sample in this study. The obtained results indicated that the prepared UV-WFPUA material could provide excellent protective properties for simulated iron artifacts.

Hierarchical Porous BiOCl/LDHs Composites Templated from Cotton Fibers for Efficient Removal of Dyes from Aqueous Solution

Hierarchically structured BiOCl/LDHs composites with well-developed porosity and high surface area have been prepared by an in situ growth of BiOCl on the surfaces LDHs fibers, and their adsorption capacities and photocatalytic activities are investigated by using methylene blue (MB) as model pollutants. The results indicate that the BiOCl/LDHs composites possess high surface area up to 126.2 m2/g. The as-prepared BiOCl/LDHs composites exhibited higher adsorptive ability and improved photocatalytic activity compared to bare BiOCl particles and LDHs fibers based on the removal of MB in aqueous solution, showing that BiOCl/LDHs composites can be used as efficient environmentally friendly materials for dye wastewater treatment.

Preparation, thermal property and morphology analysis of waterborne polyurethane-acrylate

A series of waterborne polyurethane-acrylate (WPUA) dispersions were prepared with isophorone diisocyanate (IPDI), polyether polyol (NJ-210), dimethylol propionic acid (DMPA), hydroxyethyl methyl acrylate (HEMA), different proportions of methyl methacrylate (MMA) and ethyl acrylate (MMA and EA) and initiating agent by the emulsion co-polymerization. The structures, thermal properties and morphology of WPUA films were characterized with FT-IR, DSC, SEM and AFM. Performances of the dispersions and films were studied by means of apparent viscidity, particle size and polydispersity, surface tension and mechanical properties. The obtained WPUA have great potential application such as coatings, leather finishing, adhesives, sealants, plastic coatings and wood finishes.

Effect of different photoinitiators on the properties of UV-cured electromagnetic shielding composites

Abstract A series of UV-cured electromagnetic shielding composites (UV-EMSC) containing different content of graphene oxide (GO) were prepared with oligomer, acrylate active diluents and different photoinitiators (Darocur 1173, Irgacure 184 or Irgacure 651). To fabricate conductive oligomer with low resistivity, polyurethane-acrylate (PUA) was used as the polymer matrix to help construct two-dimensional conductive networks consisting of GO. For forming conductive network structure, the surface functional groups (-OH, -COOH) of GO served as slightly conductive particles bonded with -NCO from the chain of polyurethane. The UV-EMSC exhibited a low resistivity of approximately 402 Ω·cm and an outstanding enhanced electrical conductivity of 249 mS/m at a GO content of 0.0200%. The effects of different photoinitiators on the properties of UV-cured films were investigated. The results indicate that the prepared UV-EMSC has great potential applications in different regions, such as in coatings of electronic, electrical, communications, plastic coatings and wood finishes.