Homogeneous Blend PVDF Porous Membrane Without Pore-Forming Agent for Water Treatment

Heterogeneous blending and addition of pore-forming agents are common methods to prepare porous membranes, but they are easy to form large interface pores on the surface and inside of the membrane, which affects the mechanical properties and rejection performance, while homogeneous blending has better system compatibility, forms homogeneous interface surface pores, is not easy to form macroporous defects, and the obtained membrane has better structure and mechanical properties. Therefore, PVDF homogeneous blended membranes were prepared, in this study, by homogeneous blending without adding pore-forming agents. The partial compatibility of the homogeneous blending system promoted the formation of homogeneous interface pores and improved the membrane structure stability and mechanical properties. The pure water flux of the homogeneous blended PVDF membrane was 18.54 L·m⁻²·h⁻¹·bar⁻¹, which was 8 times higher than that of the pure PVDF membrane, and the protein rejection rate was maintained at 92.83%. The strength and elongation at break of the homogeneous blended PVDF membrane were 5.63 MPa and 28.26%, respectively. The mechanical properties were better than the heterogeneous blended membrane reported in the literature, mainly because of the formation of homogeneous interface pores, which enhanced the membrane structure stability and improved the mechanical properties.