INVESTIGADORES
MANFREDI Liliana Beatriz
artículos
Título:
RELATIONSHIP BETWEEN THERMAL PROPERTIES, MORPHOLOGY AND CRYSTALLINITY OF NANOCOMPOSITES BASED ON POLYHYDROXYBUTYRATE
Autor/es:
D.A.DAMICO; L. B. MANFREDI; V.P.CYRAS
Revista:
JOURNAL OF APPLIED POLYMER SCIENCE
Editorial:
JOHN WILEY & SONS INC
Referencias:
Año: 2012 vol. 23 p. 200 - 208
ISSN:
0021-8995
Resumen:
Polyhydroxybutyrate (PHB) has a significant instability at temperature close to the melting point. The aim of this work was to improve the thermal resistance of PHB by the addition of small amounts of two different types of clays: Cloisite® Na+ (CNa+) and Cloisite® 15A (C15A). C15A has more hydrophobic character and interlayer distance than CNa+. It was observed that the addition of the organically modified montmorillonite (MMT) increased by more than 15ºC the thermal resistance of the PHB while the addition of CNa+ reduced it. This result was related to the different morphology of the final materials. The maximum in the degradation temperature of the nanocomposites with 4% of clay was in accordance with the maximum in the percentage of crystallinity. On the other hand, the interlayer gallery distance of the C15A was higher than the CNa+ in the PHB matrix, according to the better thermal stability of the C15A due to the higher barrier effect and the lower chain mobility. A slight increase in the Young modulus of the polymer was observed with the addition of C15A, due to the compatibility between the modified montmorillonite and PHB. The calorimetric and microscopy results showed that clays did not accelerate the formation of PHB spherulites nucleus, but the lamellar velocity was accelerated.