TABLE OF CONTENTS Perfluorinated sulfonic acids (PFSAs) have unique properties and require special handling. Even though PFSAs are as thermally and chemically stable as polytetrafluoroethylene (PTFE), they are vastly different from PTFE. PFSAs are highly hydrophilic in comparison with total hydrophobicity of PTFE. PFSAs are acidic whereas PTFE is neutral. Skin contact with PFSAs is safe because of the immobility of acid groups inside the polymer structure. This chapter describes safe handling procedures and precautions that should be followed with perfluorinated sulfonic acids.
Fluorinated ionomer products in the precursor form, in general, do not require special precautions in handling and storage. Products in the ionic form (hydrogen, sodium, potassium, etc.) are subject to mechanical damage, particularly when folded or creased. In addition, products in the free sulfonic acid form also tend to pick up contaminants from the environment. For more information about standard safety practices please refer to Nafion Safety in Handling and Use Bulletin and the material safety data sheet. Chlor-alkali customers should refer to Nafion User's Guide. All three guides are available from DuPont Company (www.Nafion.com).
Damage by sharp objects obviously must be avoided. Sharp folding will leave a permanent set in a sheet. Most damaging is folding in two different directions (like a table cloth). For storage, large sheets can be rolled up on a core of at least 5 cm, preferably 10 cm diameter.
Products in the free sulfonic acid form will pick...
