The rapid heating of carbon-fiber reinforced polymer matrix composites leads to complex thermo-physical interactions which not only are dependent on the thermal properties of the constituents and microstructure but are also dependent on the thermal transport between the fiber and resin interfaces. Thus, it necessitates a need to better understand the behavior of carbon fiber/matrix interfaces from the perspective of thermal transport. Using atomistic molecular dynamics simulations, the thermal conductance across the interface between a near-surface region of carbon fiber and bismaleimide (BMI) matrix is estimated as a function of the several interface and bulk features of the carbon fiber. The surface of the carbon fiber is modeled as sheets of graphitic carbon with (a) varying degrees of surface functionality, (b) varying defect concentrations in the surface-carbon model (pure graphitic vs. partly graphitic), (c) varying orientation of graphitic planes at the interface, (d) varying degree of interface passivation (dangling vs saturated bonds), (e) varying degrees of surface roughness, and (f) incorporating high conductive fillers (carbon nanotubes) at the interface. Thereafter, thermal energy exchange is investigated in terms of interface thermal conductance across the carbon fiber and the matrix. It is observed that modifications in the studied parameters (a–f) lead to significant modulation of thermal conductance across the interface and, thus, showcases the role of interface tailoring and surface-carbon morphology toward thermal energy exchange. More importantly, the results provide key bounds and a realistic degree of variation to the interface thermal conductance values at fiber/matrix interfaces as a function of different surface-carbon features.

Modeling the role of bulk and surface characteristics of carbon fiber on thermal conductance across the carbon-fiber/matrix interface

2019 Spring National Meeting

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