Otro
Kinetic study of crystallization of PHB in presence of hydroxy acids
Registro en:
Journal of Thermal Analysis and Calorimetry. Dordrecht: Springer, v. 97, n. 2, p. 525-528, 2009.
1388-6150
10.1007/s10973-009-0358-z
WOS:000271108200025
0000-0002-7984-5908
Autor
Souza, Josiane de Lima
Kobelnik, Marcelo
Ribeiro, Clovis Augusto
Vieira Capela, Jorge Manoel
Crespi, Marisa Spirandeli
Resumen
Poly(3-hydroxybutyrate), PHB, has been structurally modified through reaction with hydroxy acids (HA) such as tartaric acid (TA) and malic acid (MA). The crystallization kinetic of the samples was evaluated by isoconversional method through nonlinear fitting to obtain the estimation for activation energy (E (a) ) and pre-exponential (A) values. The thermal behavior of the crystallization temperature, 44.8 and 58.9 A degrees C at 5 A degrees C/min, and results obtained to the average activation energy, 73 +/- A 9 kJ mol(-1) and 63 +/- A 1 kJ mol(-1), to PHB/MA and PHB, respectively, are suggesting that malic acid may be deriving plasticizer units from its own PHB chain. PHB/TA show increase in the medium value of E (a), 119 +/- A 2 kJ mol(-1) and T (c) = 48.2 A degrees C (at 5 A degrees C/min), indicating that tartaric acid is probably interacts in different way to the of PHB chain (E (a)=73 +/- A 9 kJ mol(-1), T (c) = 44.8 A degrees C at 5 A degrees C/min). Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)