Oreste Tarallo

Publications (4)1.53 Total impact

• Article: Advanced materials based on polymer cocrystalline forms

  Gaetano Guerra, Christophe Daniel, Paola Rizzo, Oreste Tarallo
  Journal of Polymer Science Part B Polymer Physics 01/2012; 50(5):305 - 322. · 1.53 Impact Factor
• Article: Layers of Close-Packed Alternated Enantiomorphous Helices and the Three Different Uniplanar Orientations of Syndiotactic Polystyrene

  Alexandra R. Albunia, Paola Rizzo, Oreste Tarallo, Vittorio Petraccone, Gaetano Guerra
  [show abstract] [hide abstract]
  ABSTRACT: Thorough analyses of X-ray diffraction patterns of syndiotactic polystyrene (s-PS) films, exhibiting different crystalline and co-crystalline phases, and related evaluations of degrees of orientation have allowed to give a more accurate as well as simpler description of the three known uniplanar orientations. This new description involves the three simplest orientations of the high density ac layers (i.e. of the layers of close-packed alternated enantiomorphous s-PS helices) with respect to the film plane. On this basis it is proposed that the three uniplanar orientations should be named ac, ac and ac, i.e., by a nomenclature which also presents the advantage to be independent of the helical crystalline or co-crystalline s-PS phase.
  10/2008;
• Article: Nanoporous Polymer Crystals with Cavities and Channels

  Vittorio Petraccone, Odda Ruiz de Ballesteros, Oreste Tarallo, Paola Rizzo, Gaetano Guerra
  [show abstract] [hide abstract]
  ABSTRACT: A cheap, commercial, and easy-to-process hydrocarbon polymer (syndiotactic polystyrene, s-PS) can be crystallized in two different nanoporous phases (δ and ε) that show large uptake of several guest molecules and hence are suitable for applications in chemical separations and air/water purification as well as in sensorics. The recently discovered ε phase of s-PS is characterized by channel-shaped cavities crossing the unit cells along the c axis rather than by isolated cavities as observed for the already known δ phase. Guest sorption from the δ and ε nanoporous phases eventually leads to two different classes of polymer cocrystals, where planar guest molecules present their planes roughly perpendicular and parallel to the polymer chain axes. The ε phase channels allow cocrystal formation with guest molecules much longer than the chain axis periodicity and, due to possible reactions between guest molecules, open the possibility to achieve new hybrid materials.
  05/2008;
• Article: An Intercalate Molecular Complex of Syndiotactic Polystyrene

  Vittorio Petraccone, Oreste Tarallo, Vincenzo Venditto, Gaetano Guerra
  [show abstract] [hide abstract]
  ABSTRACT: The crystal structure of the molecular complex of syndiotactic polystyrene (s-PS) with bicyclo[2.2.1]hepta-2,5-diene (norbornadiene, NB) is presented. In analogy to the already described s-PS molecular complexes, this structure presents a monoclinic unit cell (cell constants a = 17.5 Å, b = 14.5 Å, c = 7.8 Å, and γ = 107.8°) in which the s(2/1)2 polymer helices and guest molecules are packed according to the space group P21/a. However, the structure of the s-PS/NB complex presents layers of contiguous guest molecules alternated with layers of enantiomorphous polymer helices and hence can be described as an intercalate phase. On the other hand, all the known structures of other s-PS molecular complexes present isolated molecules (or a couple of small molecules) into the cavities typical of the nanoporous s-PS δ form and hence can be described as clathrate phases. The molar ratio between the monomeric unit and the guest is 2/1 for the s-PS/NB intercalate phase, while it is generally 4/1 for the s-PS clathrate phases.
  07/2005;