We report the preparation, mechanisms and thermal properties of core-shell structured polymer/inorganic nanoparticle composite microspheres prepared by Pickering emulsion polymerization. Stable Pickering emulsion was firstly fabricated by using surface-modified nano-SiO2 particles as stabilizer. And then, two kinds of polystyrene/nano-SiO2 (PS/SiO2) composite microspheres with different sizes and morphologies were synthesized using hydrophobic azobisisobutyronitrile (AIBN) and hydrophilic ammonium persulfate (APS) as initiator, respectively. The possible mechanisms of Pickering emulsion polymerization initiated by different initiators were proposed according to the results of transmission electron microscope (TEM) and scanning electron microscope (SEM). The chemical structure and molecular weight of the composite microspheres were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffractometer (XRD) and gel permeation chromatography coupled with a multi-angle laser light scattering photometer (GPC-MALLS). Thermogravimetric analysis (TGA) and differential scanning calorimeter (DSC) were used to comparatively analyze the thermal properties of nanocomposites and corresponding pure polymer. The results indicated that the decomposition temperature and glass transition temperature (Tg) of nanocomposites were elevated to a certain degree due to the existence of nano-SiO2

This article selects studies on the preparation of fluorinated polyurethane-nano-alumina composite coating materials, and analyzes the anti-wear, water resistantance, and surface microstructure. Attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) shows that the polyurethane synthesized in this study does not contain hydrophilic –CH2OH groups. The cavitation wear test depicts that the actual cavitation amount C of the Al2O3-FPU (4) (fluorinated polyurethane) coating is 0.9035 × 10−3 kg, and the anti-wear ability increases by 61.9% compared with FPU-0.5. The water-resistant test shows that the contact angle of water droplets on the surface of the coating increase from 95.3° of FPU-0.5 to 123.1° of Al2O3-FPU (4), and the water absorption decreases from 2.52% to 1.04%. Scanning electron microscopy (SEM) observation confirms that alumina particles can protrude on the coating surface and resist strong wear, while the C-F chain with high bond energy at the near-surface exhibits high strength and water resistance, which prevents wear from spreading deep into the coating. Differential scanning calorimetry (DSC) results show that the Tg(HS) value of the hard segment phase decreases with higher external force. Notably, when the coating is subjected to erosion, which enhances the crystallinity of the hard segment phase, the tensile strength of the hard segment phase of the coating surface is improved, which supports the wear resistance. Herein, we show that the addition of nano-alumina to fluorinated polyurethanes can control high water and abrasion resistance.