The cyclopolymerization of a symmetrical nonconjugated diolefin, diallylamine (DA), initiated by peroxomonosulfate (PMS), proceeded only in the presence of ultrasound. The rate of polymerization showed a first-order dependence on DA and a half-order dependence on PMS concentration. The results are adequately explained through a proposed mechanism involving alternate intramolecular and intermolecular propagation reactions. The rate parameters for the cyclopolymerization are evaluated. The role of ultrasound in the initiation of cyclopolymerization is discussed. (c) 2005 Wiley Periodicals, Inc.