2 research outputs found
Robust and Elastic Polymer Membranes with Tunable Properties for Gas Separation
Polymer
membranes with the capability to process a massive volume of gas are
especially attractive for practical applications of gas separation.
Although much effort has been devoted to develop novel polymer membranes
with increased selectivity, the overall gas-separation performance
and lifetime of membrane are still negatively affected by the weak
mechanical performance, low plasticization resistance and poor physical
aging tolerance. Recently, elastic polymer membranes with tunable
mechanical properties have been attracting significant attentions
due to their tremendous potential applications. Herein, we report
a series of urethane-rich PDMS-based polymer networks (U-PDMS-NW)
with improved mechanical performance for gas separation. The cross-link
density of U-PDMS-NWs is tailored by varying the molecular weight
(<i>M</i><sub>n</sub>) of PDMS. The U-PDMS-NWs show up to
400% elongation and tunable Young’s modulus (1.3–122.2
MPa), ultimate tensile strength (1.1–14.3 MPa), and toughness
(0.7–24.9 MJ/m<sup>3</sup>). All of the U-PDMS-NWs exhibit
salient gas-separation performance with excellent thermal resistance
and aging tolerance, high gas permeability (>100 Barrer), and tunable
gas selectivity (up to αÂ[<i>P</i><sub>CO<sub>2</sub></sub>/<i>P</i><sub>N<sub>2</sub></sub>] ≈ 41 and
αÂ[<i>P</i><sub>CO<sub>2</sub></sub>/<i>P</i><sub>CH<sub>4</sub></sub>] ≈ 16). With well-controlled mechanical
properties and gas-separation performance, these U-PDMS-NW can be
used as a polymer-membrane platform not only for gas separation but
also for other applications such as microfluidic channels and stretchable
electronic devices
Effect of Binder Architecture on the Performance of Silicon/Graphite Composite Anodes for Lithium Ion Batteries
Although
significant progress has been made in improving cycling
performance of silicon-based electrodes, few studies have been performed
on the architecture effect on polymer binder performance for lithium-ion
batteries. A systematic study on the relationship between polymer
architectures and binder performance is especially useful in designing
synthetic polymer binders. Herein, a graft block copolymer with readily
tunable architecture parameters is synthesized and tested as the polymer
binder for the high-mass loading silicon (15 wt %)/graphite (73 wt
%) composite electrode (active materials >2.5 mg/cm<sup>2</sup>).
With the same chemical composition and functional group ratio, the
graft block copolymer reveals improved cycling performance in both
capacity retention (495 mAh/g vs 356 mAh/g at 100th cycle) and Coulombic
efficiency (90.3% vs 88.1% at first cycle) than the physical mixing
of glycol chitosan (GC) and lithium polyacrylate (LiPAA). Galvanostatic
results also demonstrate the significant impacts of different architecture
parameters of graft copolymers, including grafting density and side
chain length, on their ultimate binder performance. By simply changing
the side chain length of GC-<i>g</i>-LiPAA, the retaining
delithiation capacity after 100 cycles varies from 347 mAh/g to 495
mAh/g