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Copolymerization of γ‐butyrolactone and β‐butyrolactone
Author(s) -
Lee Chan Woo,
Urakawa Ryuichi,
Kimura Yoshiharu
Publication year - 1997
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.1997.021980414
Subject(s) - copolymer , monomer , polymer chemistry , reactivity (psychology) , chemistry , polymer , polyester , catalysis , molecule , nuclear magnetic resonance spectroscopy , stereochemistry , organic chemistry , medicine , alternative medicine , pathology
The copolymerization of a 4‐membered β‐butyrolactone (βBL) and a thermodynamically stable 5‐membered γ‐butyrolactone (γBL) proceeds in the bulk state with BF 3 · OEt 2 as a catalyst at room temperature to give poly[(3‐hydroxybutyrate)‐ co ‐(4‐hydroxybutyrate)] (P(3HB‐ co ‐4HB)) whose structure is identical with that of a polyester formed by microorganisms. The copolymer structure was confirmed by 1 H and 13 C NMR spectroscopy. The monomer reactivity ratios were r (γBL) = 0.48 and r (βBL) = 0.58, respectively, and the unit composition of 4HB increases to 56% at high γBL to βBL ratio in the feed. End group analysis of the copolymer suggests the presence of a hydroxyl group and a carboxyl group at the ends of each polymer molecule. It was postulated that the monomers activated by BF 3 react with the hydroxy group derived from the water contaminant in the monomers.