We previously copolymerized 2-bromo-3-hydroxypropionic acid (BrH) with glycolic acid (GA) and lactic acid (LA) by acid-catalyzed polyesterications of the comonomer mixtures to produce a functional group on the backbone of poly(lactic acid-co-glycolic acid).1 However, the molecular weight of the copolymers were less than those of the PLA homopolymers, and the molecular weight of the copolymers decreased with increasing amounts of BrH and GA. This paper will compare the polymerizations of trimers of BrH and GA end-capped with LA units, to that of the corresponding 2:1 comonomer mixtures in order to study the comonomers' relative reactivities, as well as the properites of the resulting sequence-controlled vs. random copolymers. The LA-capped trimers were prepared in analogy to the protection/deprotection routes of Meyer, et al.,2although not exactly the same. As outlined in Scheme 1, the LA-capped trimers were polymerized at both room temperature using carbodiimide coupling, and at elevated temperature by acid-catalyzed polyesterification. We will also present the synthesis and polymerization of two brominated dimers (BrH-LA and LA-BrH).Scheme 1. Synthesis of sequence-controlled brominated PLA.References 1. Pugh, C.;  Banerjee, A.;  Storms, W;  Wright, C. 'Functional Biodegradable Polyesters', WO 2012/015481, filed July 28, 2011.  2. Stayshich, R.S.; Meyer, T. Y. J. Polym. Sci. Part A: Polym Chem. 2008 , 46, 4704-4711.

Synthesis of sequence-controlled brominated PLA and its copolymers by protection/deprotection methods

248th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.