Polyesters from renewable resources: Organocatalytic strategies for controlled polymerization reactions

POLY 260

Robert M. Waymouth, waymouth@stanford.edu1, James L. Hedrick, hedrick@almaden.ibm.com2, Russell C. Pratt, rcpratt@us.ibm.com2, F. Nederberg, fnederberg@almaden.ibm.com3, Bas G. G. Lohmeijer, basloh@us.ibm.com2, Darcy A. Culkin1, Olivier Coulembier, Olivier.Coulembier@umh.ac.be1, Nahrain E. Kamber, nkamber@stanford.edu1, Wonhee Jeong, wonhee@stanford.edu1, Matthew K. Kiesewetter, isotope@stanford.edu1, and Eun Ji Shin1. (1) Department of Chemistry, Stanford University, Stanford, CA 94305, (2) IBM Almaden Research Center, 650 Harry Road, San Jose, CA 95120, (3) IBM Research Center, Almaden Research Center, 650 Harry Rd, San Jose, CA 95120
We have developed a family of organocatalysts for the controlled polymerization of lactones to well-defined polyesters of novel architectures and macromolecular topologies. N-heterocyclic carbenes, thio-ureas, and guanidines are potent catalysts for the ring-opening polymerization of lactones. These organocatalysts are both selective and highly active, exhibiting characteristics of living polymerization with turnover frequencies as high as 18 per second with turnover numbers up to 1000. In the presence of alcohols, N-heterocyclic carbenes are potent catalysts for the ring-opening polymerization of lactide to generate linear polylactides. In the absence of alcohols, N-heterocyclic carbenes mediate the polymerization of lactide to cyclic polylactides of high molecular weight and narrow molecular weight distribution.
 

Polymers from Renewable Resources
8:20 AM-11:45 AM, Monday, August 20, 2007 Westin Boston Waterfront -- Douglas, Oral

Division of Polymer Chemistry

The 234th ACS National Meeting, Boston, MA, August 19-23, 2007