Polymer grafted gibbsite nanoplatelets via direct initiator tethering and surface-initiated atom transfer radical polymerization

An efficient method for the preparation of polymer grafted gibbsite nanoplatelets (NPs) was proposed by direct preparation of initiator-tethered gibbsite (gibbsite-Br) NPs followed by surface-initiated atom transfer radical polymerization (SI-ATRP) to obtain gibbsite particle brushes. By adding portion of water-soluble solvent (e.g., alcohol), individual ATRP initiator-tethered gibbsite NPs were fabricated using 2-bromo-2-methylpropionic acid as a tetherable initiator avoiding the aggregation of gibbsite NPs which are ready for polymer grafting process. To verify the efficiency of the tethered initiator, various polymers grafted gibbsite NPs were fabricated by SI-ATRP. The results indicated that initiator anchored gibbsite NPs and various gibbsite-g-polymers (e.g., gibbsite-g-poly2-(dimethylamino) ethyl methacrylate, gibbsite-g-polyacrylonitrile, gibbsite-g-polymethyl methacrylate) were synthesized successfully. The thermal stabilities of gibbsite-g-polymer hybrid materials have been enhanced significantly. Compared with PMMA matrix, the fire-retardant behavior of gibbsite-g-polymethyl methacrylate was strengthened due to the incorporation of gibbsite NPs. This work proposed a versatile and convenient method for producing initiator-immobilized solid NPs and polymer grafts, which thereby enables promised properties of polymer hybrid materials depending on the orientation and interactions of particle brushes.