Anomalous ductility in thermoset/thermoplastic polymer alloys

作者：Mukherji Debashish; Abrams Cameron F^*

来源：Physical Chemistry Chemical Physics, 2009, 11(12): 2113-2115.

DOI：10.1039/b818039c

Mechanical properties of highly cross-linked polymer (HCP) networks, e. g., thermosets, can be significantly modified by adding linear polymer chains, e. g., thermoplastics. In this work, we study thermoset/thermoplastic polymer alloys by means of large scale molecular dynamics simulations (MD) of a coarse-grained model. We focus here on the effect of the linear chain fraction, Gamma(1), on the mechanical properties of HCP network for a fixed chain length. Our MD simulations show that the ductility (measured by the strain-to-fracture) of an alloy decreases with increasing Gamma(1) up to a threshold fraction, Gamma(1)*, beyond which it increases with Gamma(1). We find that for Gamma(1) < Gamma(1)* the fracture is predominantly cohesive, while for Gamma(1) > Gamma(1)* adhesive failure occurs. We suggest that the possible origin of this unexpected non-monotonic behavior is due to a competition between (a) growth of microvoids which stores mechanical energy and is compromised as Gamma(1) increases, and (b) reduction of cross-linker density with increasing Gamma(1).

• 出版日期2009