Abstract
The diffrences between 1, 4-hexadiene (1, 4-HXD) -EPDM and ethylidenenorbornene (ENB) -EPDM as tread polymers were studied putting emphasis mainly on processability, abrasion resistance and flex crack resistance.
In order to eliminate other factors and clarify the differences between termonomers, molecular weight or composition fractionation, polymerization under the same conditions and blend of polymers were performed.
And it was found that there is not any particular diffrence between ENB-EPDM and 1, 4-HXD-EPDM in hardness, 300% modulus, tensile strength, elongation, resilience, heat build-up and skid resistance when polymers of the same molecular structural factors such as molecular weight and composition distribution are compared. But ENB-EPDM was found to be inferior to 1, 4-HXD-EPDM in abrasion resistance and flex crack resistance. These differences might be ascribable to structures of crosslinkage, branching degree and other structural factors of higher orders in which termonomers play an improtant roll, and further studies are required to clarify the relation between these differences and termonomers.
