| abstract |
The present invention is directed to ultrafiltration membranes comprising a microporous material, said microporous material comprising:n (a) a polyolefin matrix present in an amount of at least 2 percent by weight, (b) finely divided, particulate, substantially water-insoluble silica filler distributed throughout said matrix, said filler constituting from about 10 percent to about 90 percent by weight of said microporous material substrate; and (c) at least 35 percent by volume of a network of interconnecting pores communicating throughout the microporous material. nn The present invention is also directed to methods of separating suspended or dissolved materials from a fluid stream such as a liquid or gaseous stream, comprising passing the fluid stream through the ultrafiltration membrane described above. |