Impact modifiers for PVC

With the exception of most PVC pressure pipe and a few profile applications where high modulus is the major consideration, most rigid and semirigid PVC compounds have impact performance requirements that can be met only through the use of impact modifiers. We present an overview of the mechanisms of impact modification and the effects of impact modifier type and concentration, interaction with other formulation ingredients, and PVC morphology as they are influenced by processing conditions. Typical end use formulations are given to illustrate the selection and use of impact modifiers for various applications.