Porex is a micro-expanded PTFE product that allows gasses to permeate but has a high barrier for liquid water. Porex can be used in instances where gas permeation is desired, but liquid is not. This material is perfect for vents, gas/liquid separation membranes, etc. It is not a Proton Exchange Membrane (PEM) material like Nafion and is a non-conductive insulator.

The evolution of the battery to more energy-dense, rapid-charging systems has brought new uses for porous materials such as membranes, separators, catalytic support, and fuel cell membranes. Battery systems can still expand with heat and contract during normal use, so numerous venting configurations are offered to equalize battery pressure and to allow heat flow. Advanced electrode materials, diffusion barriers, and electrolyte carriers are also available to optimize performance in a variety of battery and fuel cell configurations.

Porex Microporous PTFE Breathable Membranes Offer:

• High water intrusion pressure resistance

• High temperature use

• High tensile strength

• IP 65, 66, 67 & 68 ratings

• UL-94 V-0 rating @ 0.1 mm, 5VA rated @ 0.75 mm

• UL 746C rated

Porex PM21M Membrane Properties Sheet

Membrane Properties
Thickness	130 microns (5.1 mil)
Max Temperature	260°C (500°F)
Water Intrusion Pressure	350 mb
Airflow ml/min/cm2 @ 70mb	1500
Filtration >99.99%	0.5 microns
Salt Fog	No pen.