Thin-film composite poly(esteramide)-based membranes

The permeation and chlorine tolerance of various thin-film composite poly(esteramide) membranes were investigated. The membranes were synthesized interfacially by reacting trimesoyl chloride with an aqueous phase containing m-phenylene diamine plus either m-aminophenol (m-AP), bisphenol-A. (Bis-A) or hydroquinone (HQ). The amount of ester groups actually incorporated in the membranes at various starting stoichiometric ratios was quantified. Membranes incorporating Bis-A or HQ gave complete sucrose rejection while the salt rejections decreased in the order: HQ > m-AP > Bis-A based systems. The HQ:m-PDA system showed permeation characteristics approaching those of polyamide membranes synthesized from m-PDA alone. The membrane chlorine tolerance was significantly increased by the incorporation of ester linkages.