Group-Transfer Polymerization of tert-Butyl Methacrylate and [3-(Methacryloxy)propyl]pentamethyldisiloxane:  Synthesis and Characterization of Homopolymers and Random and Block Copolymers

• Published in: Chemistry of materials 1996-09, Vol.8 (9), p.2272-2281
• Main Authors: Gabor, Allen H, Ober, Christopher K
• Format: Article
• Language: English
• Subjects: Applied sciences; Copolymerization; Exact sciences and technology; Organic polymers; Physicochemistry of polymers; Preparation, kinetics, thermodynamics, mechanism and catalysts
• ISSN: 0897-4756; 1520-5002
• DOI: 10.1021/cm960012c

A synthetic approach for preparing block copolymers consisting of both a [3-(methacryloxy)propyl]pentamethyldisiloxane (SiMA) block and tert-butyl methacrylate (t-BMA) block using group-transfer polymerization (GTP) was developed. The SiMA polymerizes slowly with oxyanion catalysis but at reasonable rates using bifluoride catalysis. A model reaction eliminated a possible explanation for the slow rate of polymerization of SiMA with oxyanion catalyzed GTP. For high conversion of t-BMA to be achieved, additional bifluoride catalyst had to be added to the reactor after the t-BMA addition. Often, especially at −44 °C, after the polymerization stalled, additional conversion of the t-BMA did not occur until a critical concentration of bifluoride catalyst was established. After this level was reached, the polymerization of t-BMA occurred quickly and to high conversion.