Amphiphilic block copolymers as bile acid sorbents:: 1.: Synthesis of polystyrene-b-poly(N,N,N-trimethylammoniumethylene acrylamide chloride)

The systematic investigation of the synthesis of polystyrene-b-poly(N,N,N-trimethylammoniumethylene acrylamide chloride) was accomplished by employing both polystyrene-b-poly(tert-butyl acrylate) and its hydrolyzed derivative, polystyrene-b-poly(acrylic acid) (PS-b-PAA) as starting materials, and coupling them with N,N-dimethylethylenediamine (DMED). The various reactions and intermediates we examined include aluminum amides. acid chlorides, and imides derived from carbodiimides, all in a variety of solvents. We present below our investigation of several synthetic routes and conclude that the carbodiimide coupling of PS-b-PAA with DMED followed by quaternization and counterion exchange is the most effective method of achieving the target. A brief discussion of the merits of each procedure in the context of block copolymers is given. and IR spectroscopic evidence for the postpolymerization synthesis of the poly (acrylamide) block is provided.