We report on the application of biodegradable cyclic poly(L-lactide) (PLLA) as new stabilizer; synthesis and application of a cyclic PLLA-clay hybrid material as recyclable catalyst support. Cyclic PLLAs were used to stabilize palladium nanoparticles synthesized by a wet chemical method. It was found that the palladium particles were smaller with cyclic PLLA stabilizer (approximate to 5-10 nm) than the particles obtained from linear PLLA. The cyclic PLLA-clay hybrid was prepared by a zwitterionic ring-opening polymerization catalyzed by in situ-generated N-heterocyclic carbene catalyst. Palladium (0) nanoparticles were supported and well dispersed on the cyclic PLLA-clay hybrid to form a new nanocomposite. The nanocomposite was found to be a highly efficient and recyclable catalyst for the aminocarbonylation reactions of aryl halides with various amines. (c) 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4167-4174