Preparation of PS/Ag microspheres and its application in microwave absorbing coating

PS/Ag microspheres were prepared by electroless silver plating on PS microspheres. The PS microspheres with the average size of 1.6 μm were obtained by dispersed polymerization. Pretreatment was performed to adsorb palladium catalytic active centers on the PS surface, prior to plating. Effect of reaction temperature and loadage was studied. The proper temperature for electroless silver plating is determined to be 20 °C, and the loadage should be restricted in the range of 2.80–3.50 g to achieve ideal silver coating. It is found that the density decreases from 2.82 g/cm3 to 2.32 g/cm3 while the loadage increases from 2.86 g to 4.29 g. SEM, EDS, and XRD proved the successful formation of silver coating on PS microspheres. A waterborne microwave absorbing coating, based on PS/Ag microspheres and waterborne acrylic resin as binder, was developed. The result shows that nearly 70% of the incident wave is absorbed by this microwave absorbing coating in the frequency range of 10–18 GHz.