Core-functionalized star polymers by transition metal-catalyzed living radical polymerization. 1. Synthesis and characterization of star polymers with PMMA arms and amide cores

A series of microgel core-functionalized star-shaped polymers were synthesi zed by the polymer linking reaction method in RuCl2(PPh3)(3)-catalyzed livi ng radical polymerization. The synthesis was achieved by the polymer linkin g reaction method; i.e., functionalized divinyl compounds were added in sit u to the solution of linear living poly(MMA)s prepared with the Ru(II)-cata lyzed living radical polymerization. The functionalized microgel cores thus obtained contained acrylamide and methacrylamide. Also, star polymers with varying densities of the microgel cores were prepared from diacrylamides w ith various lengths and structures of the spacer, and by changing the relat ive amounts of MMA (arm length) and divinyl compound (core size) to initiat or, a variety of core-functionalized star polymers could be obtained in hig h yield, These core-functionalized star-shaped polymers have f of 20-640, M -w of 3.3 x 10(5)-1.3 x 10(7), and R-z of 5-42 nm. These results indicated that the cores carry as many as 440-51 000 amide groups in microgel network s.