Molecular Dynamics Study for Self-sensing/Self-healing Materials to Simulate Damage Detection and Repair in Thermoset Polymer Matrix

摘要

The mechanochemical response of a novel cyclobutane-based mechanophore(force-sensitive molecule) covalently bonded with an epoxy-based thermoset polymermatrix is characterized by experiments and modeling. This new mechanophore consistsof one cyclobutane (stress-sensitive molecular unit) and six amine groups (epoxy curingagents) that enable the cyclobutane to be connected to epoxy network chemically.Thereby the external force applied to mechanophores directly through the epoxynetwork, which makes the sensitivity of mechanophore to the external stimulationimproved. Furthermore, the mechanical properties of epoxy can be preserved sincemechanophores are connected to the host materials chemically, not embeddedphysically. The experimental results indicated that the yield strength slightly increasedcompared to the neat epoxy with improved optical response of mechanophore to theexternal mechanical loads. In parallel, molecular model of this new mechanophoreembedded thermoset polymer system has been developed. Numerical simulationscorrectly capture the effect of the new mechanophore on the improvement in sensitivityof mechanophore activation and mechanical properties; the modeling framework isvalidated experimentally.