Simultaneous Stiffening, Strengthening and Toughening of Acrylic Rubber by Miscible Blending with Poly (Vinylidene Fluoride)

Acrylic rubber (ACM) blended with poly (vinylidene fluoride) (PVDF) exhibited the simultaneous stiffening, strengthening and toughening. They also showed improvement of oil resistance while some residual strains remained after cyclic test. The stiffening of the blend rubber was ascribed to the high modulus of PVDF crystal. In-situ wide-angle X-ray scattering measurements were carried out to reveal the mechanism of the simultaneous strengthening and toughening. Newly oriented ACM chains, which would be originated from entanglement with oriented amorphous chains of PVDF, appeared during stretching. In addition, crystallinity of PVDF was found to decrease during stretching in the high strain region. Therefore, effect of stretch of the ACM chains would strengthen the blend rubber, and the partial destruction of PVDF crystal would dissipate the concentrated stress, which would toughen the blend rubber.