Yes, that (nail polish) might work — in advance.
I don’t think one could roll an already frayed end back into a thin thread held together by the nail polish. The adhesion of the nail polish to latex or vinyl gloves would likely be as great or greater than the nail polish’ adhesion to the Kevlar fibers.
However, let’s say one needs a 2 ft. section of thread with no fraying at either end. If the fraying at the loose end is under 3/4”, one could thinly “paint” on nail polish from 3/4” to 1-1/4”, and again from 24-3/4” to 25-1/4”. Let dry, then cut at 1” and 25”.
Some sources seem to indicate similar, with shellac or even white glue may work.
I have not yet seen any method that will “fix” an already frayed end, however, the way moisture will work with cotton string.
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