To improve the membrane’s anti-swelling and anti-mechanical damage properties, a sandwich structure Polypropylene/Polydimethylsiloxane/Polyamide (PP/PDMS/PA)composite membrane was fabricated as substitute for traditional dual-layer PDMS/PA composite membrane. In the sandwich structure, top PP layer protected the fragile active layer-PMDS layer, which was inlaid outside in the PDMS/PA membrane, from directly exposing to the complex fermentation broth and the external mechanical damage; middle dense PDMS functioned as the separation layer and glued the PP and PA layer together; bottom porous PA functioned as the supportive layer and enhanced the mechanical property. The swellings of the PP/PDMS/PA membrane in water, ethanol and fermentation broth were 153%, 141% and 175%, which were decreased by 21%, 6% and 17%, respectively, compared with those of the PDMS/PA membrane. The Tensile strength, Young’s modulus, breaking strength and anti-impact property of the PP/PDMS/PA membrane were 21 MPa, 218 MPa, 19 MPa and 24 N, which were increased by 223%, 18%, 724% and 196%, respectively, compared with that of PDMS/PA membrane. During separation for ethanol water solution, the flux and separation factor of the PP/PDMS/PA membrane were 956 gm-2h-1 and 8.4, respectively. During the separation for fermentation broth, the PP/PDMS/PA membrane performed better anti-fouling features compared with PMDS/PA membrane
