Rubbertoughened

Rubber-toughened, sometimes written as rubber-toughened plastics, refers to polymers in which a rigid or brittle matrix is modified by a dispersed rubbery phase to improve impact resistance and fracture toughness. The approach is widely used for thermoplastics and thermosets and can preserve stiffness and dimensional stability while reducing brittleness.

Mechanism: Energy dissipation during deformation occurs as rubber particles cavitate, debond from the matrix, and promote localized plastic shear around cracks. This creates toughening mechanisms such as crack deflection, bridging, and shear yielding. Effectiveness depends on the rubber type, particle size and distribution, and interfacial adhesion between the rubber and the matrix.

Common systems include elastomeric particles such as styrene-butadiene rubber (SBR), polybutadiene, natural rubber, and core-shell rubber particles with rubber cores and protective shells. Matrices frequently modified include polycarbonate, nylon (polyamide), polyesters, polystyrene, and acrylonitrile-butadiene-styrene blends. CSR particles can maintain transparency in some transparent plastics.

Manufacturing approaches include melt blending of elastomeric modifiers, in-situ polymerization to form grafted elastomer particles, and dispersion of CSR particles. Important design considerations are maintaining adequate stiffness and heat resistance, controlling particle size and distribution, and minimizing processing difficulties due to viscosity changes.

Applications span automotive components, electronic housings, consumer products, and packaging where higher impact resistance is needed without a large loss of stiffness. Rubber toughening is a mature technology with many commercially available toughened plastics and tailored modifiers for specific performance goals.