Interfacial Morphology and Autohesion of A-B-A Triblock Copolymers
The tensile-recovery response, optical transparency, and autohesion properties of an A-B-A triblock copolymer where A is polystyrene and B is polybutadiene have been analyzed in terms of the interfacial mechanisms of reversible bonding. This study indicates that cavitation and void formation accompanies the characteristic initial yielding and cold drawing of this polymer system. Tensile stress-strain curves are described by a theoretical function that defines both the loss and regain of interfacial continuity between the continuous B phase and the discrete A phase domains. The study indicates the initially formed cavities act as light scattering centers. Under prolonged tensile stress these cavities coalesce to produce visible void structures. Both types of defects disappear after sufficient recovery time to regenerate the original optical and mechanical response of the undeformed material.
KeywordsTriblock Copolymer Peel Testing Centrifugal Casting Interfacial Morphology Cold Drawing
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