Relationship of Processing Conditions to Structure and Properties in PMDA‐ODA Polyimide

Abstract

A combined wide angle X-ray diffraction (WAXD)/small-angle X-ray scattering (SAXS)/scanning electron microscopy (SEM)/density study of structure and morphology was carried out for a large series of pyromellitic dianhydride-oxydianiline (PMDA-ODA) polyimide (PI) samples processed using different powder metallurgy techniques. Using a combined DSC/creep rate spectroscopy (CRS)/long-term creep resistance (LTCR) approach, their molecular dynamics, thermal and elastic properties, and creep resistance in the temperature range from 20 to 4708C were also studied. Both a choice of the method of formation of fine PI particles and the order of applying high pressure relative to high temperature to form the monolithic samples led to the observation of significant property differences. Relationships between the processing conditions, structure, and properties were determined. As a result, the conditions for optimizing certain PMDA-ODA polyimide properties, especially creep resistance and elastic properties at extreme temperatures, were determined.

Effects of aromatic regularity on the structure and conductivity of polyimide‐poly(ethylene glycol) materials doped with ionic liquid

“…The more streamlined, less bulky aromatic portion of the polymer chain is more rigid and planar. The rigidity and planarity lead to a regularity in the orientation of the repeat unit of the polyimide that manifests as an ordered structural feature on the length scale of a few nanometers . The rigidity and planarity of these less bulky aromatic rings give these polymers certain orientations and regularity that are not present in a flexible linear backbone polymer that is able to coil into a wider range of configurations.…”

3D Printing All‐Aromatic Polyimides using Mask‐Projection Stereolithography: Processing the Nonprocessable

“…The polyimide based on pyromellitic dianhydride and 4,4′‐oxydianiline (PMDA–ODA or Kapton) is an all‐aromatic, engineering thermoplastic with a T g of 420 °C and a melting point ( T m ) above T d . It is commonly available in film form, and an energy‐intensive molding process is the only current method to prepare 3D structures of PMDA–ODA . Structures produced using this method offer limited resolution and complexity.…”

Electrospinning of in situ and ex situ synthesized polyimide composites reinforced by titanate nanotubes

“…The DSC curve of pure, neat polyimide fibers shows a characteristic endothermic peak at 407 ºC of relatively narrow width, which can be associated with glass transition [Figure (a)]. The reported T g for pure ODA‐PMDA polyimide is within that range of temperatures …”