To characterize the nano CaCO3 on the mechanical properties of the porous membranes, stress-strain curves of membranes were recorded and the results are shown in Table 2 andFigure 4a . The neat membrane manifested a tensile strength of 4.7 MPa. The tensile strength increased with the increased adding mass of CaCO3. Specifically, the tensile strength of cellulose/CaCO3-0.5 membrane reaches 5.8 MPa. In particular, cellulose/CaCO3-1 manifests a tensile strength of as high as 7.7 MPa, which is 63.8% increase compared to that of the initial membrane. Additionally, the introduction of nano CaCO3 also slightly affects the elongation at break of the membrane. The elongations at break of neat CA, cellulose/CaCO3-0.5 and cellulose/CaCO3-1 membranes are 6.0%, 6.8% and 5.6%, respectively.