Controlled Synthesis of Linear Polymers with Highly Branched Side Chains by "Hypergrafting": Poly(4-hydroxy styrene)--hyperbranched Polyglycerol.

Linear polymers with hyperbranched side chains are unusual macromolecular structures due to their high number of functional groups in the side chains as well as their potential cylindrical conformation in bulk or solution. In a three-step synthesis combining anionic and oxy-anionic polymerization, hyperbranched polyglycerol was "hypergrafted" from linear poly(4-hydroxy styrene) macroinitiators to yield poly(4-hydroxy styrene)--hyperbranched polyglycerol. Successful grafting with control over molecular weight (10-31 kg·mol) and low PDIs (<1.4) was shown by various characterization techniques. All polymers have a high side chain density, due to rapid transfer of the initiating functional groups to the linear backbone. DSC studies give insight into the thermal properties of the resulting polymers.