Impact modifiers improve the toughness of plastics, especially brittle polymers like PVC, polystyrene, or some nylons. They are typically elastomeric materials (rubber-like) dispersed within the polymer matrix, absorbing and dissipating impact energy.
Used in automotive parts, pipes, housings, and construction materials, they prevent cracking under sudden stress or low temperatures. While they enhance durability, they may slightly reduce stiffness or heat resistance, so formulations must balance performance needs.