|208. Simon, P.F.W.; Müller, A.H.E.: Kinetic Investigation of SelfCondensing Group Transfer Polymerization, Macromolecules 37, 7548 (2004)|
Copyright © 2004 American Chemical Society
Kinetic Investigation of Self-Condensing Group Transfer Polymerization
Makromolekulare Chemie II and Bayreuther Institut für Makromolekülforschung, Universität Bayreuth, D-95440 Bayreuth, Germany
Received December 11, 2003
Revised Manuscript Received June 13, 2004
Hyperbranched methacrylates were synthesized by self-condensing group transfer polymerization (SCGTP) of 2-(2-methyl-1-triethylsiloxy-1-propenyloxy)ethyl methacrylate (MTSHEMA) and characterized by multidetector SEC and 13C NMR. Depending on the reaction conditions, molecular weights up to Mw = 38 000 at a polydispersity of Mw/Mn 3.8 could be obtained. Kinetic measurements showed that cyclization, i.e., the intramolecular reaction of a functional group with the polymer's vinyl group, limits the molecular weights and lowers the polydispersity. A maximum degree of branching of DB 0.4 and a reactivity ratio of the propagating and initiating groups in the range of 13 < r < 23 were determined. Slow addition of MTSHEMA to the monofunctional initiator, 1-methoxy-3-(trimethylsilyloxy)-2-methyl-1-propene (MTS), enabled the control of molecular weights and decreased the polydispersity to Mw/Mn 2.8. The addition of methyl methacrylate (MMA) to a living MTSHEMA core yielded a "hyperstar" polymer.