Synthesis of Polyimides in Molecular-Scale Confinement for Low-Density Hybrid Nanocomposites

4 years ago

Synthesis of Polyimides in Molecular-Scale Confinement for Low-Density Hybrid Nanocomposites

Geraud Dubois, Jade I. Fostvedt, Willi Volksen, Reinhold H. Dauskardt, Scott G. Isaacson, Jeffery W. Baur, Krystelle Lionti, Hilmar Koerner

In this work, we exploit a confinement-induced molecular synthesis and a resulting bridging mechanism to create confined polyimide thermoset nanocomposites that couple molecular confinement-enhanced toughening with an unprecedented combination of high-temperature properties at low density. We describe a synthesis strategy that involves the infiltration of individual polymer chains through a nanoscale porous network while simultaneous imidization reactions increase the molecular backbone stiffness. In the extreme limit where the confinement length scale is much smaller than the polymer’s molecular size, confinement-induced molecular mechanisms give rise to exceptional mechanical properties. We find that polyimide oligomers can undergo cross-linking reactions even in such molecular-scale confinement, increasing the molecular weight of the organic phase and toughening the nanocomposite through a confinement-induced energy dissipation mechanism. This work demonstrates that the confinement-induced molecular bridging mechanism can be extended to thermoset polymers with multifunctional properties, such as excellent thermo-oxidative stability and high service temperatures (>350 °C).

Publisher URL: http://dx.doi.org/10.1021/acs.nanolett.7b03725

DOI: 10.1021/acs.nanolett.7b03725