Anomalous ductility in thermoset/thermoplastic polymer alloys: An explanation based on overlap concentration and cavity growthDebashish Mukherji and Cameron F. Abrams
Department of Chemical & Biological Engineering, Drexel University - Philadelphia, PA 19104, USA
received 4 September 2009; accepted in final form 9 November 2009; published December 2009
published online 7 December 2009
Using large-scale molecular-dynamics simulations, we investigate the mechanical behavior of thermoset/thermoplastic polymer alloys. We focus here on the effect of linear-chain mass fraction , for different chain lengths Nl, and strain rates . Our results show that tensile strain (i.e., strain to break) decreases with increasing up to a threshold value , beyond which it increases with . This non-monotonic behavior, which we call “anomalous ductility", is qualitatively independent of and Nl, so long as fracture occurs in bulk. However, for larger strain rates (i.e., ) adhesive fracture occurs and no anomalous ductility is observed. decreases with increasing Nl and we observe microscopic evidence that signifies the onset of interchain interactions. A simple scaling argument suggests that is related to the overlap concentration c* of the thermoplastic homopolymer in the cured thermoset matrix.
61.41.+e - Polymers, elastomers, and plastics.
87.15.La - Mechanical properties.
87.10.Tf - Molecular dynamics simulation.
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