Editorial Type:
Article Category: Research Article
 | 
Online Publication Date: 15 Jun 2021

CHARACTERIZING THE HYDROGEN TRANSPORT PROPERTIES OF RUBBERY POLYMERS BY GRAVIMETRIC ANALYSIS

,
,
, and
Page Range: 688 – 703
DOI: 10.5254/rct.21.79880
Save
Download PDF

ABSTRACT

We develop an ex situ technique to quantitatively analyze the transport properties of hydrogen gas dissolved under high pressure in rubbery polymers, such as cylindrical and spherical samples of nitrile butadiene rubber (NBR), ethylene propylene diene monomer (EPDM), and fluoroelastomer (FKM), which are potential sealing materials for hydrogen energy infrastructures. The technique consists of real-time gravimetric measurements during the desorption of hydrogen gas from samples using an electronic balance and a self-developed analysis program to determine the total charge (CH0), diffusivity (D), solubility (S) and permeability (P) of hydrogen. Dual absorption behavior is found for all three rubbers as the charging pressure increases. CH0 follows Henry's law at low pressures of up to ∼25 MPa, whereas the Langmuir model applies at high pressures. No significant pressure, size, or shape dependences are observed for D and P. The measured P values are consistent with those from the literature within the combined uncertainty evaluated. The effect of a carbon black filler mixed into rubber is discussed with respect to S and D. This method can be applicable as a standard test for the transport properties versus the pressure of various polymers irrespective of sample shape.

Copyright: 2021
Fig. 1.
Fig. 1.

Flowchart showing the algorithm of the diffusion analysis program.

Fig. 2.
Fig. 2.

Procedure for measuring the charge, solubility, diffusivity, and permeability of hydrogen using an electronic balance.

Fig. 3.
Fig. 3.

Time-dependent hydrogen concentration curve of a spherical FKM sample. (Left) Fitting image of the diffusion parameters (CH0 and D) using the diffusion analysis program and (right) the graph replotted using data and the simulation results.

Fig. 4.
Fig. 4.

Evaluation of the stability of a Sartorius electronic balance considering variations in temperature and humidity over 3 days using a standard weight of 10 g.

Fig. 5.
Fig. 5.

Effect of heat treatment on rubber mass versus elapsed time.

Fig. 6.
Fig. 6.

Charge (left) and diffusivity (right) of hydrogen gas as a function of pressure for cylindrical samples of (a) NBR, (b) EPDM, and (c) FKM rubber.

Fig. 7.
Fig. 7.

Volume dependence of permeability for cylindrical NBR samples.

Fig. 8.
Fig. 8.

Comparison of permeability for rubber samples.

Fig. 9.
Fig. 9.

Hydrogen transport as a function of pressure: (a) penetrated hydrogen content (CH0) and (b) diffusivity (D) for spherical samples of NBR, EPDM, and FKM.

Fig. 10.
Fig. 10.

Correlation between the (a) solubility and (b) diffusivity and filler content of three rubbers; NF denotes a rubber without a CB filler. Drawn fitting curve is arbitrary and intended to show the diffusivity decreases with increasing filler content.

Contributor Notes

*Corresponding author. Ph: 82-55-772-1402; email: chungks@gnu.ac.kr
Received: 01 Dec 2020
  • Download PDF