Comparative study on the effects of water pressure on water absorption of ultra‐high molecular weight polyethylene and polyformaldehyde

Abstract

The water absorption of ultra‐high molecular weight polyethylene (UHMWPE) and polyformaldehyde (POM) in different hydrostatic pressure has been investigated by means of high pressure immerse experiments and molecular dynamics simulation. Experiment results showed that water absorption of UHMWPE and POM tended to decrease with the rise of environmental pressure of water within 0 ~ 3 MPa. Water absorption of POM was far greater than UHMWPE under all kinds of hydraulic pressure. When the pressure is 3 MPa, the water absorption of POM is reduced by about 15.2% compared with that under normal pressure, while that of UHMWPE is reduced by about 41.64%. Simulation results showed that water molecules were bonded with UHMWPE molecular chain by means of Van der Waals force, and water molecules were bonded with POM molecular chain by means of Van der Waals force and hydrogen bonds, which provided potent theoretical support for the water absorption properties of UHMWPE and POM.