Mechanism of ACR Toughening

ACR is an acrylic acid acetate rubber elastomer, which is a core shell copolymer. Introduction of ACR manufacturer: There are many opinions about the shear mechanism of ACR, but the theory of "craze shear band" can reasonably explain the phenomenon of PVC toughened by elastomer impact modifier at present. According to this theory, the elastomer plays a stress concentration role in PVC products. When the material is impacted, the stress around the equator of the elastomer particles is amplified. With the increase of the distance from the particles, the amplified stress rapidly reduces to the original stress level. In addition, the stress moves from the equator of the elastomer particles to the two poles, and reaches the minimum at the poles. ACR introduction: The reason why elastomer can become the stress concentration center is that its modulus is far from that of PVC resin. The stress is concentrated on the elastomer particles A large number of crazes will be generated, and then shear bands will be formed, which will absorb the impact force and prevent the damage of the PVC molecular chain of the matrix resin. Another function of elastomer is to prevent the growth of craze through self deformation and cavitation, and prevent craze from further expanding into cracks, which will damage the matrix material, thus playing a role in resisting impact and increasing shear.