abstract |
Disclosed herein are soft and stiff compositions, i.e., compositions which have a flexural modulus that is greater than the value that is expected based on the composition's hardness. The compositions preferably have a hardness/modulus relationship represented by the formula n H ≦11.889 Ln( M )+42,n n where H is the hardness of the composition, in JIS-C, and M is the flexural modulus of the composition, in ksi; or a softness/stiffness relationship represented by the formula n if M <56, then H ≦8.5218 Ln( M )+26.5n n if M ≧56, then H ≦8.5218 Ln( M )+28.5,n n where H is the hardness of the composition, in Shore D, and M is the flexural modulus of the composition, in ksi. |