Abstract
Shape memory polymer (SMP) has been attracting attention in recent years, and expected to the application to the deployable structures in the fields of medical and aerospace. Though SMP is often used in the form of composite material to reinforce its mechanical properties, shape recovery properties of SMP are greatly affected by filler reinforcement. Shape recovery is related to the sub-micron behavior of molecules at glass transition process. Therefore, we used a coarse-grained molecular dynamics simulation to analyze the relaxation behavior of polymer composites. We focused on the temperature dependence of the energy relaxation time after the uniaxial tensile test, and evaluated the effects of intermolecular forces, nano filler reinforced composites and existence of void. The simulated results show that relaxation time becomes longer as intermolecular forces are strong. It is because intermolecular forces capture particles and disturb the relaxation. In the case of filler and void, relaxation time becomes long by the effects of filler and short by the effects of void. In addition, at high temperature, we found that the affection of filler on relaxation was weak, while the affection of void on relaxation was strong. These results imply that the glass transition temperature will rise by filler reinforcement and drop by existence of void.
