Study of Viscoelastic Properties of Petroleum Products Using Impulsive Stimulated Brillouin Scattering (CAT#: STEM-ST-0146-YJL)

Introduction

Viscoelasticity refers to the comprehensive properties of fluid viscosity and elasticity. During processing, polymers usually change from solid to liquid (melting and flowing), and then from liquid to solid (cooling and hardening), so the polymer will exhibit the properties of solid and liquid under different conditions during processing, That is, it exhibits elasticity and viscosity. However, due to the long-chain structure of polymer macromolecules and the stepwise nature of macromolecular motion, the deformation and flow of polymers cannot be purely elastic and purely viscous. The response of plastic to stress has the dual characteristics of elastic solid and viscous fluid, which is called viscoelasticity.
Petroleum products such as gasoline or oils tend to age over time with iterative thermocycles, leading to a degradation in quality. To investigate this aging process, spectroscopy techniques involving nonlinear four-wave mixing have been recently used to shed light on the viscoelastic properties of these materials.