Unmodified polymers viz, PVC, PMMA, PSSAN are brittle. Even PC, PA or PE will exhibit a brittle to ductile & limited impact strength, In order to satisfy end-use requirement for rigid applications, In Acrylic ( Impact Modifier ) in rigid PVC formulation, To get the required impact strength in rigid polymers.The quality of dispersionThe adhesion to the polymer matrixThe rubber domain particle size in the matrixThe rubber glass transition temperature