Synthesis, hydrogen absorption properties and molecular simulation of Alkyne-PVA

An organic hydrogen-absorbing material has been prepared by grafting an alkynyl group onto the polymer chain of poly(vinyl alcohol) (PVA) via an etherification reaction and a carbamate reaction to form a alkyne-rich polymer. This material shows broad application prospects in the field of hydrogen adsorption in high-vacuum multi-layer insulation sandwich. The molecular structure and degree of grafting of the product were characterized using nuclear magnetic resonance spectroscopy , and its hydrogen adsorption performance was evaluated. Additionally, molecular modeling was conducted on Alkyne-PVA, and the adsorption performance of the Alkyne-PVA polymer system for H 2 was investigated at the microscopic level through molecular simulation . The Monte Carlo method was employed to investigate the adsorption process of Alkyne-PVA on hydrogen at temperatures of 77 K, 90 K, 273 K, and 298 K, with pressures varying from 1 × 10 −5 Pa to 1 × 10 4 Pa. The results demonstrate that the adsorption of hydrogen on Alkyne-PVA is an exothermic process, and low temperature and high pressure facilitate this process. The stable adsorption configuration and adsorption energy of −0.96 eV after hydrogen adsorption on Alkyne-PVA were determined using DFT and transition state (TS) search methods, indicating that the process is thermodynamically favorable. • Alkyne-PVA is produced by grafting alkynyl groups to PVA, and its application is in H 2 absorption in MLI. • The maximum adsorption capacity of Alkyne-PVA is 903.81 Pa L/g by the H 2 adsorption test. • The adsorption of H 2 by Alkyne-PVA was simulated using molecular dynamics and GCMC simulations. • DFT and TS search indicates that the stable structure of Alkyne-PVA after adsorption of H 2 is symmetrical.