the integrity of the potted seal has been shown to test the strength of the bond between the fiber and the potted assembly a pull test has been developed that measures the force required to extract a single fiber from the potted end of the bundle or break the fiber attempting extraction the test consists of using a chatillon force gauge on an individual fiber from one of the potted ends of the bundle the bundle is placed under the slotted support bracket to hold it in place an individual fiber is randomly selected placed through the slotted support bracket and tied to a u201c j u201d hook attached to the top of the force gauge the force gauge is activated and extends upward pulling on the individual fiber to achieve separation from the potted bundle or breaking of the individual fiber whichever comes first once the end point is reached the machine automatically stops and displays the break force value in newtons twenty hollow fibers with an outer diameter of 1 5 mm and an inner diameter of 1 0 mm and a porosity of 55 were potted using an epoxy potting compound formulated by henkel corporation loctite u00ae for use with fluoropolymer resins two samples were prepared with the fibers for the first sample left untreated while the fibers for the second sample were treated with a corona discharge to promote adhesion with the epoxy the corona discharge consisted of five second exposures four times followed by rotation of the fiber by 90 u00b0 and repeating the treatment until the fiber had been rotated 360 u00b0 the epoxy was loctite product x263572 developed expressly for use with fluoropolymers and other low surface energy polymers.