Cellulose　graft　poly(methyl　methacrylate)　copolymers　were　prepared　by　atom　transfer　radical　polymerization　(ATRP)　in　an　ionic　liquid.　Cellulose　chloroacetate,　as　a　macroinitiator,　was　first　synthesized　by　direct　acylation　of　cellulose　with　chloroacetyl　chloride　without　any　catalysts　under　mild　conditions　in　an　ionic　liquid,　1-allyl-3-methylimidazolium　chloride　(BMIMCl).　Then,　the　macroinitiator　was　used　for　the　ATRP　of　MMA　mediated　by　the　CuBr　and　2,2＇-bipyridine　(bpy)　catalysis　system.　The　copolymerization　was　carried　out　in　BMIMCl　without　homopolymer　byproduct.　The　polymers　were　easily　separated　from　the　catalyst　when　the　ionic　liquid　was　used　as　reaction　medium.　The　grafting　copolymers　were　characterized　by　means　of　H-1　NMR,　AFM　and　GPC.　The　results　showed　that　the　obtained　copolymers　had　grafted　polymer　chains　with　well-controlled　molecular　weight　and　polydispersity,　and　the　polymerization　was　a　＂living/controlled＂　system.　Further,　through　AFM　observation,　it　was　found　that　the　cellulose　graft　copolymer　in　solution　Could　aggregate　and　self-assembly　into　sphere-like　polymeric　structure.　(C)　2009　Elsevier　Ltd.　All　rights　reserved.