25 research outputs found
Preparation, structure, properties, and applications of co-crystals and nanoporous crystalline phases of syndiotactic polystyrene
Three different co-crystalline phases of syndiotactic polystyrene with a nitroxide radical
Interactions of Volatile Organic Compounds with Syndiotactic Polystyrene Crystalline Nanocavities
The interaction of some volatile organic compounds, namely, 1,2-dichloroethane, 1,2-dibromoethane, and
1,1,2,2-tetrachloroethane, included in the δ crystalline phase of syndiotactic polystyrene (sPS) has been studied
in terms of conformation, orientation, and dynamical behavior. By combination of X-ray diffraction (XRD),
Fourier-transform infrared (FTIR), and solid-state 2H NMR analyses, it has been shown that despite the
differences in guest molecular properties (mass, boiling temperature, and volume), stable sPS/guest δ-clathrate
cocrystals are formed since the nanoporous δ crystalline form has a flexible structure able to adapt itself to
the guest molecule. As a consequence of inclusion, it has been shown that the guest diffusivity is strongly
reduced and the dynamical processes are constrained, particularly when these guests are in trans conformation.
This suggests the nanoporous sPS δ form to be an efficient tool for water and air purification through volatile
organic compound absorption
Polymorphism of Syndiotactic Polystyrene: gamma Phase Crystallization Induced by Bulky Non-Guest Solvents
A Clear-Cut Experimental Method to Discriminate between In-Plane and Out-of-Plane Molecular Transition Moments.
Layers of Close-Packed Alternated Enantiomorphous Helices and the Three Different Uniplanar Orientations of Syndiotactic Polystyrene.
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 a//c//, a//c⊥ and a⊥c//, i.e., by a nomenclature which also presents the advantage to be
independent of the helical crystalline or co-crystalline s-PS phase