alexa An Ab Initio Investigation of the Chain-Length Dependence of the Addition–Fragmentation Equilibria in RAFT Polymerization
Bioinformatics & Systems Biology

Bioinformatics & Systems Biology

Journal of Theoretical and Computational Science

Author(s): Ching Yeh Lin, Michelle L Coote

Abstract Share this page

Ab initio molecular orbital theory has been used to study and explain the effects of chain length on the addition–fragmentation equilibrium constant in reversible addition–fragmentation chain transfer (RAFT) polymerization. New data is presented for azobisisobutyronitrile-initiated t-butyl dithiobenzoate-mediated polymerization of methyl methacrylate, and 2-(((ethylthio)carbonothioyl)thio)propanoic acid-mediated polymerization of acrylamide, and compared with published results for a dithiobenzoate-mediated polymerization of styrene and a trithiocarbonate-mediated polymerization of methyl acrylate. The effects of primary and penultimate substituents on the addition–fragmentation equilibrium constants in RAFT polymerization can be very large (up to eight orders and four orders of magnitude respectively) and should be taken into account in kinetic models. Antepenultimate unit effects are relatively small, implying that, for most systems, chain length effects have largely converged by the dimer stage. However, for sterically bulky monomers capable of undergoing anchimeric interactions such as hydrogen bonding, the onset and convergence of these substituent effects is delayed to slightly longer chain lengths. The magnitude and direction of chain-length effects in the addition–fragmentation equilibrium constants varies considerably with the nature of the RAFT agent, the initiating species, the propagating radical, and the solvent. The observed substituent effects arise primarily in the differing stabilities of the attacking radicals, but are further modified by homoanomeric effects and, where possible, hydrogen-bonding interactions.

This article was published in Australian Journal Of Chemistry and referenced in Journal of Theoretical and Computational Science

Relevant Expert PPTs

Relevant Speaker PPTs

Recommended Conferences

Relevant Topics

Peer Reviewed Journals
Make the best use of Scientific Research and information from our 700 + peer reviewed, Open Access Journals
International Conferences 2017-18
Meet Inspiring Speakers and Experts at our 3000+ Global Annual Meetings

Contact Us

Agri, Food, Aqua and Veterinary Science Journals

Dr. Krish

1-702-714-7001 Extn: 9040

Clinical and Biochemistry Journals

Datta A

1-702-714-7001Extn: 9037

Business & Management Journals


1-702-714-7001Extn: 9042

Chemical Engineering and Chemistry Journals

Gabriel Shaw

1-702-714-7001 Extn: 9040

Earth & Environmental Sciences

Katie Wilson

1-702-714-7001Extn: 9042

Engineering Journals

James Franklin

1-702-714-7001Extn: 9042

General Science and Health care Journals

Andrea Jason

1-702-714-7001Extn: 9043

Genetics and Molecular Biology Journals

Anna Melissa

1-702-714-7001 Extn: 9006

Immunology & Microbiology Journals

David Gorantl

1-702-714-7001Extn: 9014

Informatics Journals

Stephanie Skinner

1-702-714-7001Extn: 9039

Material Sciences Journals

Rachle Green

1-702-714-7001Extn: 9039

Mathematics and Physics Journals

Jim Willison

1-702-714-7001 Extn: 9042

Medical Journals

Nimmi Anna

1-702-714-7001 Extn: 9038

Neuroscience & Psychology Journals

Nathan T

1-702-714-7001Extn: 9041

Pharmaceutical Sciences Journals

John Behannon

1-702-714-7001Extn: 9007

Social & Political Science Journals

Steve Harry

1-702-714-7001 Extn: 9042

© 2008-2017 OMICS International - Open Access Publisher. Best viewed in Mozilla Firefox | Google Chrome | Above IE 7.0 version