Hyperbranched poly(3-ethyl-3-hydroxymethyloxetane) via anionic polymerization

Anionic polymerization of 3-ethyl-3-hydroxymethyl oxetane was achieved using NaH with coinitiators benzyl alcohol (BA) or trimethylol propane (TMP). Pendent hydroxyls facilitate a multibranching polymerization. NMR confirmed the presence of linear, dendritic, and terminal repeat units. For TMP initiated polymerizations there was an acetone soluble portion which was more branched (DB=0.48) than the acetone insoluble portion (DB=0.20). Polymers were not soluble in water, ether or THF, but were partially soluble in acetone and completely soluble in methanol, benzene, chloroform, and DMSO. MALDI-TOF analysis showed relatively low molecular weights (around 500) and confirmed the presence of both cyclic and TMP endgroups.