Quantifying the synergistic effect of dispersion state and interfacial adhesion contributions on impact strength of core shell rubber-toughened glassy polymers

Abstract

Artificially made aggregates of core–shell rubber (CSR) nano-particles were latex blended with an emulsion-grade poly(vinyl chloride) (PVC), cast, dried, sintered, and annealed into soft nano-composites. The agglomeration of CSR aggregates and their interfacial adhesion evolution through thermal annealing resulted in temperature-dependent impact strength increase to a maximum, followed by its decrease. Surprisingly, the observed maxima at different annealing temperatures appeared at constant coagulant content to form the aggregates. In addition, the impact strengths of all samples showed a universal linear correlation with the annealing temperature and matrix glass transition disparity, ΔT, over the absolute average size differentiation between the agglomerated CSRs and the matrix primary particles, |ΔD|. The contribution of dispersion state, interfacial adhesion and their interplay was quantified by |ΔD|, ΔT and |ΔT/ΔD| representing 2, 20 and 39 fold impact strength improvement, respectively. The synergistically enhanced impact strength was nicely reflected in a theoretical interlayer model prediction implying double loading of the feed CSR particles.