Abstracts Book - IMRC 2018

• SB1-O014 Invited Talk
PROPERTY EFFECT OF FLUORINATED MONOMER
INCORPORATION INTO BACKBONE MATRIX OF POLYIMIDE
AEROGELS
Stephanie Vivod 1 , Maryann Meador 1 , Coleen Pugh 2
1 National Aeronautics and Space Administration, Structures and Materials, United States.
2
University of Akron, Polymer Science, United States.
Polyimides are often found in aeronautic and aerospace applications due to
their ability to retain their physical and mechanical properties over a wide range
of temperatures and in chemically demanding environments. Cross-linked
polyimide aerogels retain these same characteristics with added attributes to
their three dimensional structures such as high porosity, low density,
and extremely high surface areas. This results in materials with low dielectric
constants, enhanced acoustic impedance, and reduced thermal conductivity.
Incorporating fluorine moieties into polymers can lead to dramatic
improvements to material properties such as increased solubility in organic
solvents, lower dielectric constant, increased hydrophobicity, higher thermal
and thermo-oxidative stability, better optical transparencies, and increased
flame resistance. The characteristic properties of the 3-dimensional structures
of the polyimide aerogel, formed through gelation of dianhydrides and diamines
in polar aprotic solvents, show a wide range of dependence on polymer
concentration, monomeric structure, and crosslink density. In this study,
formulations were synthesized varying the length of the repeat unit (n),
dianhydride fraction (Pyromellitic dianhydride (PMDA) and 4, 4’-
Hexafluoroisopropylidene dipthalic anhydride (6FDA)), and the weight percent
of total polymer in solution. Previous studies have shown that the use of PMDA
in the polymer backbone results in highly transparent aerogels while 6FDA
incorporation enhances flexibility. Herein we examine and report the effect on
thermal, mechanical, and optical properties via incorporation of fluorinated
monomers into the backbone of polyimide aerogels.
Acknowledgment:
We thank Linda McCorkle (OAI) for SEM photos, Dan Scheiman (QSS) for running
thermal analysis, Spyro Efpraxias and Frank Bremenour (HX5 Sierra) for
operation of the Supercritical Fluid Extractor, and Bill Brown (NASA) for