Polycarbonate (PC) is a transparent and tough engineered thermoplastic resin that is used in many different applications. PC is generally notch sensitive, i.e. the impact resistance of PC decreases with an increase in notch sharpness. To solve this problem, PC and other amorphous polymers are toughened by addition of softer domains, such as rubbers. The purpose of rubber modification is to de-localize the stress concentration at the tip of a notch and to re-distribute the stress to individual rubber particles under the surface of the notch, which triggers toughening mechanisms, such as rubber cavitation and shear yielding. Low concentrations of hard inorganic nanofillers (&lt; 5 wt%) can also enhance the fracture properties of polymers. This is due to the large specific surface area of nanofillers that trigger toughening mechanisms, such as matrix debonding, matrix shear yielding and crazing.<br/><br/>In this presentation we will built further on these concepts by using hard nanoparticles in combination with soft additives, such as rubbers and fibrillated polymers to invoke different deformation mechanisms with the overall aim to develop a design strategy to improve toughness and crack propagation resistance in a family of PC materials.<br/><br/>Using crack propagation resistance (J-R) curves and high-resolution imaging techniques, including SEM, STEM and AFM, we will demonstrate the synergistic effects of additives in improving crack propagation resistance in PC. We will demonstrate different levels of property improvement that can be achieved by a combination of additives and the mechanistic aspects of toughening invoked by individual components in a blend.

Synergistic effects of additives to improve the crack propagation resistance in PC and PC copolymers

256th National Meeting (2018)

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