The conventional purification process of ethyl tert-butyl ether (ETBE), one of the most promising biofuels in Europe, is highly energy intensive. A membrane separation process, such as pervaporation (PV), could be a simple, clean and economical alternative. The main challenge in pervaporation is to develop high performance membranes that are both highly permeable and highly selective. A multi-block poly(urea-imide) (PUI) with outstanding selectivity and excellent film-forming character, was selected as a promising membrane polymer but its permeability had to be improved for this application. In this project, we aim at developing novel membrane materials by plasticizing this promising polymer with selective polymethacrylate soft grafts in order to increase its permeability ideally without interfering with its excellent selectivity. Novel grafted PUIs were obtained by an original synthesis scheme based on 3 orthogonal chemistries: Polycondensation, polymer functionalization and grafting by 'click' chemistry. The functional grafts were prepared by controlled radical polymerization (ATRP). Dense membranes were then obtained for the different grafted PUIs. Their sorption and permeability properties were assessed for the purification of ETBE by PV. An analysis in terms of structure-morphology-property relationships showed that membrane permeability increased strongly with the graft content while the excellent selectivity decreased very slightly. This strategy enabled to overcome the common permeability/selectivity trade-off and led to polymer membranes, which are amongst the best ones reported so far for ETBE purification. Figure 1. <img src='https://acs-archive-assets2.s3.amazonaws.com/mwrm/uploads/60844_scheme_1_diana_crain_1_.jpg' alt='' />

Multi-block copolymers grafted by "click" chemistry: A new strategy for high performance membranes for ethyl tert-butyl (ETBE) bio-fuel purification

248th National Meeting (2014)

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