The mechanical properties of polyurethane elastomers are very good, which are shown in Young's modulus, tensile strength, tear strength and load capacity.





Young's modulus and tensile strength are within the elastic limit. The ratio of tensile stress to deformation is called Young's modulus (E) or elastic modulus. When the hardness is Shaul D42 and the tensile stress is 2.25 MPa at 2.5% elongation, the Young's modulus of the polyurethane elastomer is the same as that of other elastomers, and Hooke's theorem is obeyed only at low elongation. But its Young's modulus is much higher than other elastomers. Taking Vulkollan polyurethane elastomer series products developed by Bayer Company in Germany as an example, for materials with 65A hardness, the elongation at break under elastic limit is about 5%, and the Young's modulus is about 5 MPa. For materials with 70D hardness, the above data are 2% and 600 MPa, respectively. The tensile strength of polyurethane elastomer is as high as 70 MPa, which is not comparable to that of rubber plastics. However, the reason for permanent deformation is that the tensile strength exceeds the elastic limit, especially the dynamic load.

The tear strength of polyurethane elastomer is very high, which is more than twice that of natural rubber.

Although the compressive strength of polyurethane elastomer is not high and the load capacity is not large at low hardness, the hardness of polyurethane elastomer can be increased while the elasticity of rubber is maintained, thus achieving high load capacity. Moreover, the compressive stress of polyurethane elastomer increases faster with the increase of compression ratio than that of styrene-butadiene and chloroprene rubber.