Showing papers by "Rosario Benavente published in 1997"
TL;DR: In this article, the crystallization behavior of seven fractions of a copolymer of propene and 1-hexane has been analyzed and the variation of different thermal parameters with the composition of these fractions has been analysed, as well as the crystallinity, determined by differential scanning calorimetry, X-ray diffraction and density measurements.
26 citations
TL;DR: The phenomenology of the physical ageing of glassy materials can be described by using the activation energy spectrum model as discussed by the authors, which was originally developed for relaxations in metallic and oxide glasses and applied it to a liquid crystalline polymer, poly(diethylene glycol p, p′-bibenzoate) (PDEB), in the glassy state.
Abstract: The phenomenology of the physical ageing of glassy materials can be described by using the activation energy spectrum model. This model was originally developed for relaxations in metallic and oxide glasses and this paper applies it to a liquid crystalline polymer, poly(diethylene glycol p, p′-bibenzoate) (PDEB), in the glassy state.
12 citations
TL;DR: In this article, the characteristic ratios of three samples of poly(1-hexadecene) with different tacticities were evaluated from intrinsic viscosity and molecular weight data obtained with a size exclusion chromatograph with dual (concentration plus viscoity) detector.
Abstract: The characteristic ratios of three samples of poly(1-hexadecene) with different tacticities were evaluated from intrinsic viscosity and molecular weight data obtained with a size exclusion chromatograph with dual (concentration plus viscosity) detector. No significant differences were found for the characteristic ratio in the studied range of tacticities. Theoretical calculations for the unperturbed dimensions were also performed for these samples by using the rotational isomeric state model, and compared with the experimental results.
5 citations
Journal Article•
TL;DR: In this paper, an analisis termico muestra la formacion de tres fases diferentes in el proceso de enfriamiento desde el fundido.
Abstract: Las transiciones termicas de las formas meso y R del poli [p,p'-bibenzoato de 3-metilhexametileno] se han estudiado por calorimetria diferencial de barrido. El analisis termico muestra la formacion de tres fases diferentes en el proceso de enfriamiento desde el fundido. El correspondiente estudio mediante rayos X indica que la secuencia de fases para ambos polimeros es: Sa, Sc y fase esmectica hexagonal. Sin embargo, en el ciclo de fusion el poli [p,p'-bibenzoato de (R)-3-metilhexametileno] presenta una conducta mono-tropica, frente al comportamiento enantiotropico de la forma meso. Por otra parte, el analisis mecano-dinamico muestra la presencia de tres relajaciones en ambos polimeros.
1 citations