Preparation and characterization of composite hollow fiber reverse osmosis membranes by plasma polymerization. 2. Reproducibility of the plasma polymerization process and durability of the resulting coated membrane

Abstract

The reproducibility of the plasma polymerization process was examined in a semlcontlnuous coating of hollow fibers, 6 fibers In lengths of approximately 12-15 m, by evaluating the performance of reverse osmosis membranes. The uniformity of the coating along the length of hollow fibers, as well as the reproducibility of the process, was found to be satisfactory when electrodes were conditioned In the actual conditions of plasma polymerization to be employed and plasma polymerization conditions were carefully controlled. The durability of the coated hollow fibers was then Investigated In the following test media: hot water, low pH, high pH, and 0.1 % NaOCI solutions. A threshold value of glow discharge parameter W/FM was found to be crucial In the performance of the reverse osmosis membrane and durability of the coated hollow fibers. Plasma polymerized composite membranes showed remarkable durability.