Radical polymerization is a chemical reaction that sequentially adds together small molecules (called monomers) to form long polymer chains that consist of hundreds or thousands of repeating units. Radical polymerization is a powerful synthetic method. It is used to make nearly half of all polymers (plastics), about 100 million tons worldwide each year. Atom transfer radical polymerization (ATRP) is a special type of radical polymerization that can prepare polymers with precisely controlled chain lengths. In addition, depending on the chemical structure of the monomer, it can produce a variety of shapes, such as stars, combs, brushes or rings and each of these has specialty applications. While ATRP is a common technique, some monomers, especially those with acidic functionalities, are difficult to polymerize using ATRP. Polymers formed from acidic monomers are desirable because they have unique properties that make them useful in a variety of applications. With the support of the Macromolecular, Supramolecular and Nanochemistry Program of the Chemistry Division, Professor Matyjaszewski at Carnegie Mellon University is developing ATRP methods for the controlled polymerization of acidic monomers. The project, which could enable the creation of new commercially-scaled plastics that benefit society, trains undergraduate and graduate students in polymer science. The research team also works with members of the Controlled Radical Polymerization (CRP) Consortium at Carnegie Mellon University to develop new materials for use in a range of industrial markets.
The intellectual challenge of this research comprises understanding, improving, and expanding direct ATRP of acidic monomers without neutralization or protection. Controlled ATRP of acidic monomers requires a fundamental understanding of the kinetics and thermodynamics of ATRP and the associated side reactions. New copper catalyst complexes are developed to achieve higher selectivity and stability under acidic conditions. Iron catalysts and metal-free organic photoredox catalysts are studied to further reduce an environmental impact of ATRP. New synthetic pathways are explored to economically produce acidic polymers by direct ATRP of unprotected monomers. The new polymers with well-controlled complex architectures, including organic-inorganic hybrids such as nanocomposites, functionalized surfaces, and bioconjugates are of both academic and commercial importance. The process saves time and energy and reduces cost in academic and industrial laboratories. The results of this research are disseminated through Professor Matyjaszewski's website, timely publications, student presentations at (inter)national conferences, and through the industrial CRP Consortium at Carnegie Mellon University.
