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 (R) Na(+) (CNa(+)) and Cloisite (R) 15A selleckchem (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 15 degrees C 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.

However, the interlayer gallery distance of learn more 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 MMT 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. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123: 200-208, 2012″
“Measurements of isothermal magnetization and electrical transport on Pr0.5Ca0.5Mn0.97Ga0.03O3 have selleck chemical been performed in a magnetic field up to 15 T. Two distinct metamagnetic transitions, which may relate to the collapse of the pseudo-CE-type and CE-type antiferromagnetic phases (CE, a composite antiferromagnetic structure composed of a chequeboard of alternating C and E type), have been observed in the temperature region of 2.5-140 K. Different from the traditional magnetization steps, the two metamagnetic transitions are not dependent on the field sweep rate. These peculiar features are sensitive to the microstructure of the sample. A temperature-field phase diagram has been constructed and found to exhibit a minimum critical field, similar to other phase-separated systems. (C) 2011 American Institute of Physics. [doi: 10.1063/1.