This part of GB/T 20042 specifies the terms and definitions of test methods for proton exchange membrane used for proton exchange membrane fuel cells, the thickness uniformity test, the proton conductivity test, the ion exchange equivalent weight test, the gas permeability test, tensile property test, the swelling rate test, the water absorption test, etc.
This part is applicable to all types of proton exchange membranes.
2 Normative references
The following documents contain provisions which, through reference in this part of GB/T 20042, constitute provisions of this part. For dated references, subsequent amendments (excluding corrections) to, or revisions of, any of these publications do not apply. However, parties to agreements based on this part are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest editions apply to this part.
GB/T 1040.3-2006 Plastics - Determination of tensile properties - Part 3: Test conditions for films and sheets (ISO 527-3:1995, IDT)
GB/T 1462-2005 Test methods for water absorption of fiber reinforced plastics
GB/T 6672-2001 Plastics film and sheeting - Determination of thickness by mechanical scanning (ISO 4593:1993, IDT)
GB/T 20042.1 Proton exchange membrane fuel cell - Terminology
3 Terms and definitions
For the purposes of this part, the terms and definitions given in GB/T 20042.1 and the following apply.
3.1
proton conductivity
the ability of the membrane to conduct protons is the inverse of the resistivity, expressed in S/cm
Note: It is an electrochemical index to measure the proton conductivity of the membrane, and it reflects the magnitude of proton migration velocity in the membrane.
3.2
equivalent weight (EW)
the mass of dry film contained per mole of ionic group, expressed in g/mol
Note: It is inversely related to the ion exchange capacity (IEC), which indicates the ion exchange capacity, and reflects the acid concentration in the proton exchange membrane.
3.3
tensile strength
the ratio of the maximum stretching force to the membrane thickness and width before the specimen breaks, expressed in MPa, while a stretching force is applied to a standard membrane specimen at a given temperature, humidity and stretching speed
3.4
water uptake
the amount of water absorbed per unit mass of dry membrane at a given temperature and humidity, expressed as the mass percentage (wt%)
3.5
swelling rate
the dimensional change in the transverse, longitudinal and thickness directions relative to the dry membrane at a given temperature and humidity, expressed in %
