Accession Number : ADA430036


Title :   Morphology and Viscoelastic Properties of Polystyrene Blended with Fully Condensed Polyhedral Oligomeric Silsesquioxanes


Descriptive Note : Preprint


Corporate Author : MICHIGAN STATE UNIV EAST LANSING DEPT OF CHEMICAL ENGINEERING AND MATERIALS SCIENCE


Personal Author(s) : Namani, Madhu ; Geng, Hai-Ping ; Lee, Andre ; Blanski, Rusty L


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a430036.pdf


Report Date : 18 Oct 2004


Pagination or Media Count : 38


Abstract : Polyhedral oligomeric silsesquioxane (POSS) offers a unique approach to examine the effect of molecularly dispersed nanoscopic fillers on rheological properties of entangled polymer melts. Experiments were performed using a nearly-monodisperse molecular weight polystyrene (PS) blended with varying amounts of two fully condensed POSS molecules surrounded with phenethyl and styrenyl groups. Due to the chemical similarity between these organic moieties surrounding the silicon-oxygen framework (SiO1.5) of POSS and PS, we were able to obtain polymer blends with molecular dispersed nanoscopic fillers needed to study the effect of intermolecular nanoparticle-nanoparticle interactions and the associated intramolecular interactions on the dynamics of the polymer chains. Differential Scanning Calorimetry (DSC), Wide-angle X-ray Diffraction (WAXD) and Transmission Electron Microscopy (TEM) were used to characterize the thermal properties and morphologies of the POSS/PS blends. Smallstrain oscillatory shear and/or tensile method was used to probe the dynamics of polymer chains as influenced by the addition of different chemical moiety of POSS at the glass transition, rubbery state and the terminal-flow transition regions. Results obtained from the thermal and mechanical characterization methods were compared with morphological observations to better understand the structure-property relationship of polymers containing molecularly dispersed nanoscopic fillers.


Descriptors :   *VISCOELASTICITY , *MORPHOLOGY , *POLYSTYRENE , *MIXTURES , *SILOXANES , *OLIGOMERS , THERMAL PROPERTIES , MOLECULES , X RAY DIFFRACTION , MELTS , ELECTRON MICROSCOPY , RHEOLOGY , MOLECULE MOLECULE INTERACTIONS , OSCILLATION , WIDE ANGLES , DISPERSIONS , FILLERS , NANOTECHNOLOGY , DIFFERENTIAL SCANNING CALORIMETRY


Subject Categories : Organic Chemistry
      Polymer Chemistry
      Plastics
      Atomic and Molecular Physics and Spectroscopy
      Mechanics


Distribution Statement : APPROVED FOR PUBLIC RELEASE