分子動力学法による高分子材料の変形挙動解析

抄録

Polycarbonate (PC) is an important engineering polymer that has been used as the structural material in a wide range of applications. Using coarse-grained (CG) molecular dynamics (MD), this work systematically investigates the elastoplastic deformation of PC under two tension scenarios. To drastically improve computational efficiency, a new CG force field is developed for PC based on full-atom MD simulations. Effectiveness of the force field is verified by the calculations of glass transition temperature, Young's modulus, strength, and distribution functions of bond stretching, bending and torsion. Using the newly developed force field, PC is found to undergo elastic deformation followed by the onset of yielding and plastic flow, in both uniaxial tension and constrained tension. The onset of yielding and plastic deformation are correlated with structural evolution using MD snapshots. Energy variations associated with bond stretching, bending and torsion are further analyzed to provide insights into their respective contributions to the deformation process. MD results are further compared with Argon's model, which does not only accurately predict the mechanical strength of PC, but also provides molecular-level insights into the deformation mechanisms.