Tube sheets for permeators

In a method for forming a tube sheet having a plurality of hollow fiber membranes suitable for fluid separations embedded therein comprising introducing into a mold the plurality of hollow fiber membranes and a liquid resin and then curing the liquid resin, the improvement wherein the liquid resin comprises polyglycidyl resin and imidazole curing agent have the structure ##STR7## wherein R.sub.1 is hydrogen, alkyl of 1 to about 12 carbon atoms, lower acyl or mono or bicyclic aryl or aralkyl of 6 to about 15 carbon atoms and R.sub.2, R.sub.3 and R.sub.4 are hydrogen, halogen, hydroxy, nitro, alkoxy of 1 to about 6 carbon atoms, alkyl of 1 to about 12 carbon atoms, lower acyl, or mono or bicyclic aryl or aralkyl of 6 to about 15 carbon atoms, said imidazole curing agent being provided in an amount between about 2 to 40 percent of the amount required for complete reaction through one ring nitrogen with the epoxy moieties of the liquid resin on a stoichiometric basis.