PROCESSOS PARA PRODUZIR UMA MEMBRANA COMPOSITA E PARA SEPARAR HIDROCARBONETOS AROMATICOS

摘要

Thin film composite membranes comprising a thin active selective layer deposited from a solution onto a thicker porous non-selective support layer are disclosed. In particular, a thin film of polyurea/-urethane is coated onto a microporous support substrate from a specific multi-component solvent system. Effective film thicknesses of less than 1 micron ( mu m) can be achieved, said thin films being virtually defect free. Asymmetric-composite membranes consisting of a thin active layer of polyurea/urethane on a microporous support substrate are useful for separating aromatics from saturates, especially under pervaporation or perstraction conditions.