Tensile strength and elongation at break of membranes are measured, wherein the results as Fig. 4 shown.From Fig. 4 shown the physical strength of WPU membranesare different with the different hard segment content. Obviously,the order of elongations at break is PU-8 > PU-1 > PU-3 > PU6 > PU-4 > PU-7 > PU-2 > PU-5. However,the tensile strength of PU-1membrane is approximately 1.7-fold than that of PU-8 membrane,which means TDI has rigidity benzene rings in hard segment andthat lead to higher tensile strength than that of IPDI. Similarly thehigher content of hard segment has, the bigger value of tensilestrength we get. Conversely the more content of hard segment inWPU membrane exist, the lower values of elongation at break is,just as PU-5 membrane shown in Fig. 4.