Deanna L. Gomochak, William S. Bryant, and Harry W. Gibson
National Science Foundation Science and Technology Center:
High Performance Polymeric Adhesives and Composites, and
Department of Chemistry
Virginia Polytechnic Institute and State University
Blacksburg, VA
Silica gel can be used as a model for glass in order to develop a technique for modifying the surface via a controlled/"living" radical polymerization. The two major types of controlled/"living" radical polymerizations are Stable Free Radical Polymerization (SFRP) and Atom Transfer Radical Polymerization (ATRP). The controlled/"living" radical polymerization produces polymers whose molecular weights and molecular weight distributions can be controlled as has been demonstrated in the literature for both SFRP and ATRP. In our work the initiator 2,2¢-azobis [2-methyl-N-(2-hydroxyethyl)propionamide] (VA-086) has been functionalized by trimethylchlorosilane to produce trimethylsilane azo-initiator (TMSA), which was tested for SFRP. The TMSA was prepared as a model for an azo-initiator attached to a silica gel surface. TMSA has been shown to be an efficient initiator for the SFRP of styrene. Chain extension and block copolymerization reactions have been performed on an isolated polymer prepared with TMSA and 2,2,6,6-tetramethylpiperidine-N-oxide (TEMPO).