Melamine-formaldehyde/polyvinyl alcohol (MF/PVA) composite membranes modified by nano silica (SiO 2 ) and silane coupling agent KH570 modified SiO 2 (KH570-SiO 2 ) were prepared. The surface properties and morphology of KH570-SiO 2 were characterized using fourier transform infrared spectrometer (FTIR), thermogravimetric analysis (TGA), contact angle measurement instrument and X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and particle size analyzer. The morphology and properties of nanoparticles modified MF/PVA membranes were also studied with scanning electron microscopy (SEM), TGA, dynamic mechanical analysis (DMA) and tensile tester. The results show that KH570 is grafted on the surface of nano SiO 2 . KH570-SiO 2 has better dispersion in MF/PVA resin than that of unmodified SiO 2 . The thermal stability, mechanical and crystallizing properties of MF/PVA membrane are increased after modified with nano SiO 2 . KH570-SiO 2 makes MF more compatible with PVA resin, and further increases the mechanical properties and thermal stability of MF/PVA membrane.
Hao Yanjun,Zheng Xuecheng,Fan Wei,Chen Siqi,Ye Zhongbin,Tai Lei
In view of the extremely developed bedding of shale formations, which are dominated by micro-nano pores and fractures, traditional sealing agents make it difficult to produce a tight seal on shale formations due to their huge particle sizes. Combining the bridging effect of inorganic nanoparticles and the deformation properties of organic particles, this article synthesized a core-shell structure nano-blocking agent through emulsion polymerization, which was called P(MMA-St-BD)/KH570-SiO 2 . The structure of the synthesized nano-plugging agent was characterized utilizing Fourier transform infrared spectroscopy (FT-IR), particle size distribution, thermogravimetric analysis (TGA), and transmission electron microscopy (TEM). Performance characterization was carried out through the effect of nano-blocking agents on emulsion stability, rheological properties, microporous filter membrane plugging experiments, and core pressure-bearing capacity tests. The findings demonstrate that P(MMA-St-BD)/KH570-SiO 2 ’s structure satisfies design specifications, and that the nano-plugging agent has outstanding thermal stability, homogeneous particle size distribution, and good dispersion. Its decomposition temperature also exceeds 400 °C. This study analyzed the plugging efficiency of nano-blocking agents from the temperature perspective, indicating that the nano-blocking agents seal shale formations tightly. Ultimately, through mechanism analysis, nanomaterials can squeeze and deform through the polymer shell and enter the shale micropores and micro-cracks for sealing, forming a high-strength sealing zone.
In this work, an original amphiphilic copolymer P(PEG-PDMS-KH570) combined with SiO 2 nanoparticles (SiO 2 NPs) was utilized to prepare polyether sulfone (PES) nanocomposite ultrafiltration (UF) membrane with enhanced antifouling performance. The enrichment of the organic-inorganic modifier P(PEG-PDMS-KH570)@SiO 2 were realized at the same time as the formation of PES UF membrane via sol-gel non-solvent induced phase separation (NIPS) process. The interaction between the copolymer P(PEG-PDMS-KH570) and SiO 2 NPs furnished a stable and effective antifouling PES UF membrane. Surface morphology, chemical composition characterization and wetting property measurements confirmed the segregation and distribution of the nanocomposite modifier. The multi-defense mechanism from fouling resistance to fouling release of the nanocomposite membranes was investigated by setting bovine serum albumin (BSA) aqueous solution as a model foulant. The antifouling properties of the modified membranes, especially for the PES/T@SiO 2 ∼4% membrane, were effectively improved. The flux decline rate of PES/T@SiO 2 ∼4% membrane was as low as 15.6%, and the flux recover ratio was up to 99.0%. Moreover, the modified membranes also possessed remarkable antifouling stability. Results of this work provide a facile method to construct a hierarchical and heterogeneous membrane surface that could achieve the multi-defense mechanism in efficient water treatment.
危险品化学品经营许可证（带存储）