DEVELOPMENT OF CROSS-LINKED POLY(VINYL ALCOHOL) (TYPE-II) AND PERMEATION OF ACETIC-ACID WATER MIXTURES

Crosslinked poly(vinyl alcohol) (type II) membranes where amic acid based on m-phenylene diamine was used as a crosslinking agent were prepared and tested for the prevaporation separation of acetic acid-water mixtures. A membrane containing 12 wt.% crosslinking agent was found to give optimum pervaporation results for ethanol-water mixtures. Good pervaporation results were obtained from these membranes which gave separation factors (water/acetic acid) of 34-176 and permeation rates of 12-722 g(m2-hr) depending on the operating temperature and acetic acid-water mixture composition. Arrhenius plots of permeation rates were used to determine the permeation activation energy and pre-exponential factors for the binary mixtures. Analysis of the pervaporation data were conducted by using the permeation ratio, theta, the permeation separation index (PSI), activation energy, and pre-exponential factors all of which are functions of feed composition to explain the interactions between permeants and polymer and also the plasticization action of permeants.