title: Carboxylate-induced degradation of poly(3-hydroxybutyrate)s.
abstract: This communication shows that thermal degradation of poly(3-hydroxybutyrate)s (PHBs) is induced by carboxylate groups via a newly proposed E1cB mechanism. In PHBs with end groups in the form of carboxylic acid salts with Na+, K+, and Bu4N+ counterions, the proposed mechanism explains the dependence of thermal stability on the size of the counterion. The degradation via intermolecular alpha-deprotonation by carboxylate is suggested to be the main PHB decomposition pathway at moderate temperatures. The results of the present study show the ability to control the degradation and stability of poly(3-hydroxybutyrate)s as well as of their blends via chemical structure and concentration of the carboxylate polymer end groups.
authors.affiliation: Centre of Polymer Chemistry, Polish Academy of Sciences, 34, M. Curie-Sklodowska Street, 41-819 Zabrze, Poland.
authors.forename: Michal
authors.initials: M
authors.lastname: Kawalec
authors.forename: Grazyna
authors.initials: G
authors.lastname: Adamus
authors.forename: Piotr
authors.initials: P
authors.lastname: Kurcok
authors.forename: Marek
authors.initials: M
authors.lastname: Kowalczuk
authors.forename: Ismaela
authors.initials: I
authors.lastname: Foltran
authors.forename: Maria Letizia
authors.initials: ML
authors.lastname: Focarete
authors.forename: Mariastella
authors.initials: M
authors.lastname: Scandola
mesh_terms: D002264:Carboxylic Acids / Q000737:chemistry*; D002384:Catalysis; D006885:Hydroxybutyrates / Q000138:chemical synthesis* / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D015394:Molecular Structure; D011091:Polyesters / Q000138:chemical synthesis* / Q000737:chemistry; D012680:Sensitivity and Specificity; D013696:Temperature; D013818:Thermogravimetry; D000094122:Polyhydroxybutyrates
chemical_list: D002264:Carboxylic Acids; D006885:Hydroxybutyrates; D011091:Polyesters; C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates