Method for manufacturing hollow fiber membranes

A method of potting a plurality of perfluorinated thermoplastic polymer hollow fiber membranes having an inner diameter, an outer diameter, and a porous wall between, arranged lengthwise, having two ends, wherein a portion of one or both ends of said plurality of perfluorinated hollow fiber membranes is potted with a perfluorinated thermoplastic polymer, and wherein at least one potted end is open to fluid flow through said inner diameter, said method comprising:

• a) preparing said plurality of perfluorinated thermoplastic polymer hollow fiber membranes into a fiber bundle with at least one end of said bundle restricted to flow of melted perfluorinated thermoplastic polymer potting material through the inner diameter of said fibers,
• b) making a temporary recess in an amount of a perfluorinated thermoplastic polymer potting material,
• c) placing said hollow fiber membrane bundle by the closed end in a fixed position in said temporary recess,
• d) holding said perfluorinated thermoplastic polymer potting material at a temperature below the melting point or softening point of said perfluorinated hollow fiber membranes and above the melting temperature or softening temperature of said potting material, wherein said thermoplastic polymer potting material flows around and up said hollow fiber membranes completely filling the interstitial spaces between fibers of said portion with said perfluorinated thermoplastic polymer,
• e) cooling said perfluorinated thermoplastic polymer potting material and said hollow fiber bundle to solidify said perfluorinated thermoplastic polymer potting material to form a first potted end,
• f) optionally, repeating steps a) through d) on second hollow fiber membrane ends to form a second potted end,
• g) cutting through at least one said potted ends to open said potted hollow fiber membrane ends, and,
• h) optionally, sealing unpotted hollow fiber membrane ends opposed to a cut potted end.