1 research outputs found
Free Volume Manipulation and <i>In Situ</i> Oxidative Crosslinking of Amine-Functionalized Microporous Polymer Membranes
Membranes for gas separations are limited by the trade-off
relationship
between permeability and selectivity. In this study, we demonstrate
an in situ thermal oxidative crosslinking strategy
for amine-functionalized polymers using tert-butoxycarbonyl
(tBOC) groups to improve separation performance. The use of labile
tBOC groups offers two major benefits for inducing thermal oxidative
crosslinks: (1) they trigger free radical chain reactions at more
moderate temperatures, preventing polymer backbone degradation pathways
that otherwise occur at elevated temperatures, and (2) they enable
free volume manipulation (FVM) conditions that yield increased free
volume and narrower free volume element size distribution. This thermal
oxidative crosslinking strategy is demonstrated using an amine-functionalized
polymer of intrinsic microporosity (PIM-NH2). The resulting
crosslinked polymer yielded up to a 22-fold increase in H2/CH4 selectivity while retaining 96% of H2 permeability
from pristine PIM-NH2 films. By combining thermal oxidative
crosslinks and FVM, we demonstrate an effective approach to overcome
the traditional permeability–selectivity trade-off and offer
a greater resistance to major performance stability issues like plasticization
and physical aging, making membranes better suited for industrial
applications