CATIONIC POLYMERIZATION OF 1,3-DIOXEPANE IN THE PRESENCE OF 2,2-BIS(HYDROXYMETHYL)BUTANOL

Cationic polymerization of 1,3-dioxepane (DOP) initiated by triflic ac id was carried out in the presence of 2,2-bis(hydroxymethyI)butanol (B HMB). The structure and molecular weight of the products were characte rized by GPC and NMR spectra. The results showed that molecular weight of the polyacetal obtained could be controlled by the initial mole ra tio of DOP/BHMB. GPC showed that as the mole ratio of BHMB/DOP increas ed, the content of cyclic oligomers also increased. Proton, C-13 and 2 D HMQC-fg NMR demonstrated that no hydroxymethyl group of BHMB appeare d as an end group. It was also illustrated by proton NMR that some BHM B units existed in cyclic oligomers. The mechanism of formation of cyc lic oligomers was discussed. (C) 1998 John Wiley & Sons, Inc.