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

Report Date:

2013-10-01

Pagination or Media Count:

26.0

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 ultravioletvisible UVVis 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.

Subject Categories:

  • Physical Chemistry
  • Properties of Metals and Alloys
  • Plastics
  • Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE