A new two-dimensional covalent organic polymer material (ST-1) was synthesized by the condensation of squaric acid and melamine. The preparation is simple and cheap. Fourier transform infrared spectra (FT-IR), X-ray photoelectron spectroscopy (XPS), N2 adsorption–desorption, powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) were employed to characterize the structure and properties of ST-1. This material presents the highest specific capacitance value of 177.6 F g−1 at a current density of 0.3 A g−1 in a three electrode configuration in a 6 M potassium hydroxide electrolyte. The retention rate of the specific capacitance can be maintained at about 60.24% when the current density is increased by 50 times. It is worth mentioning that ST-1 also demonstrates about 94% capacitance retention after 10 000 galvanostatic charge–discharge cycles.
Gang Xie,Yiping Hao,Yang Bai,Xiangyang Xu,Lv Xia,Ting Huang,Weichao Du,Jingjie Ge
Nano-plugging agents have become the key to efficiently extracting shale gas, which is a clean energy source. Poly(St-(1-Octene)-EGDMA) was synthesized by emulsion polymerization of 1-octene, styrene (St), and ethylene dimethacrylate (EGDMA). Fourier transform infrared spectroscopy, laser scattering, thermogravimetric analysis, scanning electron microscopy (SEM), pressure transfer experiment, and artificial mud cake plugging experiments were used to characterize poly(St-(1-Octene)-EGDMA). The results indicate that poly(St-(1-Octene)-EGDMA) has a particle size of 38.8 nm. After 16 h at 180 °C, the particle size is 49 nm. Based on thermogravimetric analysis, poly(St-(1-Octene)-EGDMA) can tolerate temperatures up to 394 °C, demonstrating excellent high-temperature stability. The rheology of the drilling fluid remains unaltered by poly(St-(1-octene)-EGDMA). With the addition of 2% poly(St-(1-octene)-EGDMA) water-based drilling fluid, the permeability decreased to 2.4 × 10–3 mD and the blocking rate increased to 50%. Simulations are performed with Ansys Fluent 19.2 to verify the experimental results. The potential plugging mechanism of poly(St-(1-Octene)-EGDMA) as a plugging agent was explored. Shale nanopores and nanofractures are invaded by poly(St-(1-Octene)-EGDMA) under pressure. Shale nanopores and nanofractures are plugged by poly(St-(1-Octene)-EGDMA). In water-based drilling fluids, poly(St-(1-Octene)-EGDMA) has a broad range of applications as a possible nano-plugging agent.
危险品化学品经营许可证（带存储）