<正>Microporous ethylene-vinyl alcohol copolymer （EVOH） flat membranes and hollow-fiber membranes with 38 mol% ethylene content were prepared via thermally induced phase separation （TIPS） using the mixture of 1

4-butanediol and poly（ethylene glycol）（PEG400） as diluents. Effects of the ratio of 1

4-butanediol to PEG400 on the phase diagrams

phase separation mechanism and membrane morphology were studied by small angle light scattering （SALS） measurements

differential scanning calorimetry （DSC）

and scanning electron microscopy （SEM）. It was found that by varying the composition of the binary solvent

the phase diagrams and membrane morphology can be controlled successfully. Moreover

the phase diagrams showed that broader regions of Liquid-Liquid （L-L） phase separation were obtained

as well as closer distances between L-L phase separation lines and Solid-Liquid （S-L） phase separation lines. Interconnected structures observed both in the flat membrane and hollow fiber membrane consist with the above results.