An efficient method to prepare silver-loaded SMA microspheres with high electrical conductivity

An effective method for preparing conductive composite microspheres based on poly(styrene‑alt‑maleic anhydride) (SMA) microspheres was developed. Cross‑linked SMA microspheres were first synthesized via self‑stabilized precipitation polymerization of styrene and maleic anhydride using divinylbenzene as the crosslinker. Based on the high reactivity of the maleic anhydride groups, abundant amino groups were modified on the surface of SMA microspheres by 1,4‑butanediamine (SMA-NH2 microspheres). These amino groups served as effective anchoring sites for the dense immobilization of silver nanoparticles (AgNPs) through in-situ reduction, creating highly active catalytic centers. Subsequent secondary silver growth, mediated by ascorbic acid, facilitated the formation of a uniform and continuous silver shell.The resulting SMA@Ag microspheres exhibited excellent electrical conductivity, reaching 2578 S/cm. Notably, this amine-mediated strategy obviates the conventional requirement for heavy-metal-based sensitizers and activators (e.g., Sn2+, Pd2+), thereby streamlining the process and enhancing its environmental sustainability. This approach provides a straightforward and eco-friendly route for the production of high-performance conductive polymer composites.