Controlled synthesis of amphiphilic poly(methacrylate)-g-[poly(ester)/poly(ether)] graft terpolymers

摘要

Graft copolymers represent valuable polymeric materials with the unique ability to vary a large variety of molecular parameters, i.e. main and side chain polymer type, degree of polymerization and polydispersity of main and side chain, graft density and distribution of the grafts (graft uniformity). Using specific controlled polymerization techniques tailor-made graft copolymers can be produced, which encounter specific needs. Such a control usually results from a combination of different "living" or controlled polymerization mechanisms. With this respect, this paper focuses on the synthesis and characterization of poly(methacrylate)-g-[poly(aliphatic ester)/poly(ether)] graft terpolymers (Scheme 1) by successively coupling atom transfer radical copolymerization (ATRP) of methyl methacrylate (MMA), 2-hydroxyethyl methacrylate (HEMA) and poly(ethylene glycol) methyl ether methacrylate (PEGMA) initiated by ethyl 2-bromoisobutyrate ((EiB)Br) and catalyzed by NiBr_2(PPh_3)_2, and the "coordination-insertion" ring-opening polymerization (ROP) of L,L-dilactide (LA) or ε-caprolactone (CL) after activation of the pending hydroxyl functions by tin (II) bix(2-ethylhexanoate) (Sn(Oct)_2).