Dynamically Crosslinked Poly(vinyl methyl siloxane) for a High-Capacity, Flexible Hydrogen Getter

Abstract

Flexible hydrogen getters are highly desired in the nuclear industry for closed space hydrogen elimination. However, research on the development of flexible getters is scarce, and the performance of existing flexible getters is far from satisfactory. As a result of the constraints imposed by covalent crosslinks in these getters, chain movement is restricted, and unsaturated groups within polymer segments cannot effectively contact palladium nanoparticles to be hydrogenated, which ultimately leads to low uptake capacity for these getters. In this work, we show that flexible getters with high uptake capacity could be obtained by dynamically crosslinking the getter network. In dynamically crosslinked hydrogen getters (DHGs), chain mobility is enhanced due to the repeated exchange of dynamic bonds, and the chances of unsaturated bonds-palladium catalyst contact are therefore greatly increased. Hydrogen absorption tests show that the uptake capacity of DHGs is higher than 80 mL (standard temperature and pressure condition, STP) per gram, much larger than covalent getters with an uptake capacity of less than 17 mL per gram. Further optimizing the recipe for preparation gives a flexible getter with an uptake capacity of 193.4 mL/g and a mechanical strength of 1.53 MPa, demonstrating the power of the current method based on dynamic design. The developed method based on the dynamic strategy is also simple and could be readily scaled-up for flexible getter production.