Yes it can be done using emulsion method.

Yes, polybenzoxazine membranes can be made for oil-water separation without using a fabric or sponge substrate. The fabrication of these freestanding membranes often involves creating a porous structure through methods like phase inversion or electrospinning.

the process typically begins with synthesizing a benzoxazine monomer. This monomer is then dissolved in a suitable solvent to create a polymer solution. A porous structure is created either by using the solution to cast a film that undergoes phase inversion, where the solvent is exchanged with a non-solvent to induce phase separation and pore formation, or by using electrospinning to create a nanofiber membrane directly from the polymer solution. The resulting porous film or nanofiber mat is then thermally cured to initiate the ring-opening polymerization of the benzoxazine, forming a cross-linked polybenzoxazine membrane. This process yields a robust, self-supported membrane with intrinsic hydrophobicity and oleophilicity, making it effective for oil-water separation.

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