Polyvinylchloride (PVC) powders containing (or not) calcium carbonate were mechanochemically modified using a ball mill. Membranes prepared by phase inversion of the modified PVC were tested by scanning electron microscopy, infrared spectroscopy, thermogravimetry, and differential scanning calorimetry to compare the structure and properties before and after mechanochemical modification. The results showed that after mechanochemical modification, pure water flux of the phase inversion PVC membrane reached up to 378.6 L/(m(2) h), significantly higher than that before modification [123.3 L/(m(2) h)]; calcium carbonate enhanced the dechlorination effect of mechanochemical modification and further increased pure water flux of the membrane to 454.2 L/(m(2) h). Mechanochemical modification increased the tensile strength of the PVC membrane by 4.1 % and decreased crystallinity of the PVC powder by about 34 %.