Oral: Deformation and failure mechanisms of graft block copolymer reinforced glassy homopolymer-homopolymer interfaces.

Recycling commercial plastics is complicated by the immiscibility of most polymers, leading to phase-separated domains with weak interfaces in polymer blends derived from mixed waste streams. Extensive research on diblock copolymer compatibilizers has deepened our understanding of emulsification of thermodynamically incompatible polymers, and enhancement of interfacial adhesion between the respective homopolymers. However, such copolymers have only a few degrees of freedom for tuning the interfacial properties. A graft block molecular architecture offers a much larger space for architectural design. To investigate strategies for improving mechanical properties of compatibilized blends, the adhesion between two immiscible glassy homopolymers in the presence of graft block copolymers at the interface has been studied using coarse-grained molecular dynamics simulations. Distinct stress transfer and failure mechanisms characterized by interfacial voiding and chain pullout are observed at low and high loadings. The effect of the number of grafts, backbone length, and graft length on toughness and strain at break will be presented. The contrasting behavior of free-end and trapped entanglements on deformation and failure is illuminated by the simulations.