A polymer having a contact angle with water that is greater than or equal to 90.degree. and a contact angle with 1,3-propane diol that is less than 90.degree.. A pervaporation membrane comprising the polymer and a process for purifying a fermentation broth using a pervaporation membrane comprising the polymer is also described.
FEDERAL RESEARCH STATEMENT
 This invention was made with government support under Grant #DE-EE000311.6 awarded by the U.S. Department of Energy. The government has certain rights in the invention.