Influence of specimen directions on recovery behaviors from circular deformation of polyester cord-inserted rubber composites

Polyester cord-inserted rubber composites cut with the parallel and perpendicular directions to the fabric cord (RC||FC and RC⊥FC specimens, respectively) were thermally aged and the recovery behaviors from a circular deformation were investigated. The permanent deformation of the RC||FC specimen was more severe than that of the RC⊥FC specimen. Recoveries of the rubber composites without fabric cord were nearly the same irrespective of the cutting directions. Sources to cause the permanent deformation were found to be the increased crystalline region of polyester cord and the increased crosslink density of rubber part.