Tensile-WAXD Apparatus: An Improved and Accurate System for the In situ Study of Extension-induced Segmental Orientation in Highly Stretched Elastomer

An improved X-ray apparatus that combines tensile testing and X-ray diffraction has been designed and constructed to conduct timeresolved experiments during uniaxial stretching. By utilizing mortise-like clamping jaws and dogbone-shaped specimens, this setup allows for the simultaneous recording of high-quality mechanical responses and 2D diffraction patterns due to the minimization of experimental errors from sample slippage or premature fracture. Furthermore, the local extension ratio can be accurately determined based on thickness variation, and the Hermans' orientation function was demonstrated to be a reliable method with high accuracy to calculate the segmental orientation parameter 〈P₂〉 in elastomeric samples under high degree of stretching. In summary, this innovative tensile-WAXD instrument has proven to be a promising and powerful technique for investigating the “stress-deformation-segmental orientation” relationship in elastomers with high extensibilities.