Prof. Dr. Axel Müller

Macromolecules, 37 (20), 7548 -7558, 2004. 10.1021/ma0358834 S0024-9297(03)05883-2
Web Release Date: September 11, 2004

Kinetic Investigation of Self-Condensing Group Transfer Polymerization

Peter F. W. Simon and Axel H. E. Müller

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 M_w = 38 000 at a polydispersity of M_w/M_n 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 M_w/M_n 2.8. The addition of methyl methacrylate (MMA) to a living MTSHEMA core yielded a "hyperstar" polymer.