Facile preparation of isocyanate-functionalized poly(styrene-co-maleimide-co-maleic anhydride) particle and its application as a versatile support for nano-sized TiO2 photocatalyst

Polymer-supported catalysts have attracted intensive research attentions due to easy handling, facile separation and outstanding recycling performance. Herein, a simple, efficient and universal strategy was developed to fabricate isocyanate-functionalized polymer microspheres bearing highly reactive surface isocyanate groups, which could serve as a versatile support for the immobilization of photocatalyst. Firstly, self-stabilized precipitation polymerization of maleimide, maleic anhydride and styrene was performed in the presence of divinyl benzene (crosslinker) to prepare imide-functionalized poly(styrene- co -maleimide- co -maleic anhydride) (PSMM) microspheres. By simply adjusting the solvent composition and monomer feed ratio, monodisperse PSMM particles with diameter in the range of 0.52–1.01 μm were successfully obtained, which were further modified with hexamethylene diisocyanate (HDI). As a proof-of-concept, TiO 2 nanoparticles were readily and covalently bound to the surface of HDI-functionalized PSMM (PSMM-HDI) particles through reaction with isocyanate groups, leading to the formation of PSMM-HDI supported TiO 2 (PSMM-HDI@TiO 2 ). Furthermore, anhydride groups on the surface of PSMM was hydrolyzed to endow PSMM-HDI@TiO 2 with better dispersibility and adsorption performance. The degradation of methylene blue under UV-light was performed to evaluate the photocatalytic performance of the resultant PSMM-HDI@TiO 2 . Compared with pristine TiO 2 , the PSMM-HDI@TiO 2 exhibited not only higher degradation efficiency, but also facile separation and better reusability.