Quantum-chemical study on the mechanical behaviour of polydimethylsiloxane under deformation: interaction with fumed silica surfaces

Silicone elastomers filled by fumed silica reveal peculiar technical behaviour. Chemical modification of the silica surface is commonly used to control the rheological and mechanical properties of uncured and cross-linked silicone elastomers. To study the microscopic aspect of the problem, quantum-chemical (QCh) modelling in the framework of originally elaborated semiempirical techniques has been performed. The response of a silicone polymer fragment, interacting with a silica model cluster, to external stress is considered in terms of a mechanochemical reaction. The impact of silicone-water and silicone-modified filler interactions on stress-strain characteristics, i.e. Young's modulus, energy and force of deformation and tensile strength have been studied on a molecular level.