Free Radical Polymerization of Dimethyl Amino Ethyl Methacrylate Initiated by Poly(3-Hydroxybutyrate Macroazo Initiator: Thermal and Physicochemical Characterization

Abstract

A novel macro intermediate based on poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) was synthesized for use in the copolymerization with dimethyl amino ethyl methacrylate (DMAEMA). Methyl amino ethanol was reacted with PHBHHx to prepare a dihydroxy terminated polyester. The hydroxyl ends of the obtained PHBHHx derivatives were capped with 4,4'-azobis cyanopentanoic acid to obtain the PHBHHx macroazo initiator (PHBHHx-AI) for free radical copolymerization of DMAEMA at 70(o)C. A steady increase in DMAEMA units in the synthesized block copolymer as a function of time was observed. The overall rate constants for the free radical polymerization of DMAEMA initiated by PHBHHx-AI was k = 2.33 x 10(- 4) Lmol(-1)s(-1). Block copolymers were characterized using the (1) H NMR, FTIR, DSC and TGA techniques.