Accession Number : ADA592039


Title :   High-Temperature Transitions in Metallopolymers Crosslinked With 2,6-bis(1'-methylbenzimidazolyl)pyridine Metal-Ligand Complex


Descriptive Note : Final rept. Sep 2012-Aug 2013


Corporate Author : ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE


Personal Author(s) : Jackson, Aaron C ; Lambeth, Robert H ; Rodriguez-Santiago, Victor ; Butler, Brady G ; Beyer, Frederick L


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a592039.pdf


Report Date : Oct 2013


Pagination or Media Count : 26


Abstract : Metallopolymers have reversible bonding properties and strong phase separation behavior that make them useful for a variety of applications. However, relaxation processes within the polymer, specifically relaxation processes within the metal-ligand (ML) rich phase, are not fully understood. This report proposes that scission of the ML bond and softening of the ML-rich phase within the polymer are the primary relaxation processes occurring above room temperature. Dynamic Mechanical Analysis (DMA) tests show that both play a role in the degradation of the mechanical properties above 100 deg C. In polymers containing cobalt and iron, the two relaxation processes were separate while these relaxation processes were interdependent in polymers containing copper and zinc. Under static conditions, no relaxation processes were evident as measured by ultraviolet/visible (UV/Vis) light spectroscopy, small-angle x-ray scattering (SAXS), and x-ray diffraction (XRD). These results highlight the importance of the ligand chemistry and counter ion, two components of metallopolymers that may have a large impact on the softening point of the ML-rich phase. They also highlight a need to study changes in the morphology and spectral response of metallopolymer under mechanical stress.


Descriptors :   *CROSSLINKING(CHEMISTRY) , *FILMS , *HIGH TEMPERATURE , *IONS , *MECHANICAL PROPERTIES , *PHASE TRANSFORMATIONS , *POLYMERS , *PYRIDINES , COPPER , DEGRADATION , DIFFERENTIAL SCANNING CALORIMETRY , LIGANDS , MONOMERS , MORPHOLOGY , NITRILES , NUCLEAR MAGNETIC RESONANCE , OXIDATION , RELAXATION , STRESSES , ULTRAVIOLET SPECTROSCOPY , X RAY DIFFRACTION , X RAY SCATTERING , ZINC


Subject Categories : Physical Chemistry
      Properties of Metals and Alloys
      Plastics
      Mechanics


Distribution Statement : APPROVED FOR PUBLIC RELEASE