title: Mechanical and Transport Properties of Poly(propylene-co-1-heptene) Copolymers and Their Dependence on Monoclinic and/or Mesomorphic Polymorphs.
abstract: Poly(propylene-co-1-heptene) copolymers have been evaluated in a wide 1-heptene content range. Two different polymorphs can be observed in this interval under the processing conditions imposed: monoclinic crystallites and mesomorphic entities. The unique presence of one or the other lattice at specific content or the coexistence of both of them at the intermediate composition interval is a key factor affecting some of the exhibited properties. The influence is observed in characteristics mainly dependent on either crystalline structure, like rigidity, or the amorphous regions, as location and intensity of glass transition. To get a deeper understanding, the transition from mesophase to monoclinic crystallites has also been studied by DSC and by WAXS and SAXS experiments using synchrotron radiation. It is observed that this transformation is only partial and just involves one-third of the initial ordered mesomorphic entities. Permeability to different gases is mainly dependent on amorphous content and hindrance that monoclinic or mesomorphic entities impose on those disordered regions.
authors: Instituto de Ciencia y Tecnología de Polímeros (ICTP-CSIC) , Juan de la Cierva 3, 28006 Madrid, Spain.
authors: Alberto
authors: A
authors: García-Peñas
authors: Instituto de Ciencia y Tecnología de Polímeros (ICTP-CSIC) , Juan de la Cierva 3, 28006 Madrid, Spain.
authors: José M
authors: JM
authors: Gómez-Elvira
authors: Grupo de Investigación "POLímeros: Caracterización y Aplicaciones" (U. A. del ICTP-CSIC), E.T.S.I. Industriales, Universidad Politécnica de Madrid , José Gutiérrez Abascal 2, 28006 Madrid, Spain.
authors: Vicente
authors: V
authors: Lorenzo
authors: Instituto de Ciencia y Tecnología de Polímeros (ICTP-CSIC) , Juan de la Cierva 3, 28006 Madrid, Spain.
authors: Ernesto
authors: E
authors: Pérez
authors: Instituto de Ciencia y Tecnología de Polímeros (ICTP-CSIC) , Juan de la Cierva 3, 28006 Madrid, Spain.
authors: María L
authors: ML
authors: Cerrada