Hydroxyfunctional oxetane-inimers with varied polarity for the synthesis of hyperbranched polyether polyols via cationic ROP

Synthesis and characterization of novel hydroxyl-functionalized oxetane-inimers with varied alkyl chain length—3-hydroxymethyl-3-methoxymethyloxetane, 3-hydroxymethyl-3-propoxymethyloxetane, and 3-hexoxymethyl-3-hydroxymethyloxetane—is reported. Cationic ring-opening polymerization of these latent, cyclic AB2-monomers leads to hyperbranched (hb) polyether polyols with degrees of branching between 34 and 69%, confirmed by inverse-gated (IG) 13C NMR spectroscopy. The hyperbranching polymerization yielded apparent molecular weights (Mn) ranging from 500 to 2500 g mol−1 (size exclusion chromatography). Remarkably, by copolymerization of 1,1,1-tris(4-hydroxyphenyl)ethane as a “focal” unit, polymerization under slow monomer addition conditions lead to higher apparent molecular weights up to 11,220 g mol−1. The end groups of the hb polymers were studied via matrix-assisted laser desorption/ionization time of flight mass and NMR spectrometry. By varying the alkyl chain length, tailoring of the solubility and glass transition temperatures of the materials is possible. Potential applications range from macroinitiators with defined polarity to tailoring of surface properties of antifouling materials. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 2850–2859