Study on dynamic mechanical properties of a nylon-like polyester tire cord

Tires might be the first technically significant composite out of rubber and play a vital role in the overall performance of a car. The essential functions of a tire rely to a great extent on the properties of tire cords. Polyester and nylon cords make up the majority of synthetic fibers used in tires. A new kind of polyester cord has been developed combining the performance characteristics of both polyester and nylon cords. This article examines the dynamic mechanical properties of this nylon-like polyester tire cord by adopting dynamic mechanical analysis, Instron, and DISC fatigue experiments, as well as its dynamic adhesion property using flex fatigue experiment. It demonstrated that the dynamic complex modulus of the nylon-like polyester cord was higher than that of nylon 6 cord but lower than that of standard polyester cord, which was a favorable characteristic when it came to replacing nylon 6 cord with nylon-like polyester cord in tires. Under cyclic loading, hysteresis loss of nylon 6 cord > nylon 66 cord > nylon-like polyester cord > standard polyester cord was observed. In the DISC experiment, nylon-like polyester had a similar compression resistance property to that of nylon 6 cord. At a temperature below 85°C, nylon-like polyester cord maintained roughly the same level of residual ratio of dynamic adhesion, but beyond this temperature point, nylon 6 exhibited a better performance.

Mechanical Properties of Aged Cord-Rubber Composites

Cord-rubber composites are usually subjected to cyclic deformation for the tire applications. Due to the hysteretic nature of the rubber, heat generation in the rubber component under dynamic cyclic loading often causes a rise in temperature, which can deteriorate the physical properties of the composites. Therefore, better understanding of the cord-rubber composites under thermal aging conditions is of great importance for the lifetime prediction. In the present work, the effective modulus of polyester cord- and steel cord-rubber composites at different aging conditions was studied by means of the mechanics of composite materials and the Arrhenius relationship based on the properties of components. It is found that the Halpin-Tsai relation with introducing the effect of thermal aging is also valid for the aged cord-rubber composites.

Effect of Material Properties on Tire Performance Characteristics—Part I. Tire Cords

The effect of modulus of tire cords in stabilizer and body plies on the performance of a radial automobile tire is discussed. Cord modulus was varied systematically by using polyester, rayon, and aramid materials. High speed, endurance, and plunger energy were not effected. Rolling resistance was higher with aramid cord than with polyester cord in the body ply, but there was no effect of cord material in stabilizer plies. Increase of cord modulus in the stabilizer ply, however, did produce significantly higher cornering coefficient. Wear resistance was also higher, especially under high severity test conditions.