Influence of Intermolecular Forces and Spatial Effects on the Mechanical Properties of Silicone Sealant by Molecular Dynamics Simulation

In the production process of silicone sealant, mineral oil is used to replace methyl silicone oil plasticizer in silicone sealant to reduce costs and increase efficiency. However, the silicone sealant content in mineral oil is prone to premature aging, which significantly reduces the mechanical properties of the silicone sealant and severely affects its service life. At the same time, there are few reports on the simulation research of the performance of silicone sealant. In this study, three mixed system models of crosslinking silicone sealant/plasticizer are constructed by the molecular dynamics simulation method, and the effect of three influencing factors, namely, crosslinking degree of silicone sealant, plasticizer content and external temperature on the mechanical properties of silicone sealant system is analyzed. The results show that at room temperature, the mechanical properties of the silicone sealant system are enhanced with the increase of its crosslinking degree; At a high crosslinking degree, with the increase of plasticizer content, the mechanical properties of the silicone sealant system show an overall decreasing trend. When the methyl silicone oil in the range of 20%, the mechanical properties of the silicone sealant appeared to be a small degree of enhancement; As the temperature increases, the doped mineral oil mechanical properties of silicone sealant declined significantly, while doped with methyl silicone oil silicone sealant and doped with double-ended vinyl silicone oil silicone sealant mechanical properties have better heat resistance. It will provide scientific theoretical guidance for improving and predicting the mechanical properties of silicone sealant.