Polymers are viscoelastic fluids that can be either elastic or viscous depending on how quickly they flow or deform. Rheology is the science of studying the behaviour of materials in a liquid state or soft solids when stress or deformation is applied to generate a reaction to an applied force. Rheology is a useful tool for understanding how polymers behave under different processing conditions and designing equipment. Understanding structure-property correlations using molecular weight, molecular weight distribution, stereochemistry, morphology, melt degradation, and processing performance is another use for rheology in the polymer area. Rheology is a discipline of physics that studies the deformation and flow of matter while it is under stress. It is especially interested in the qualities of matter that determine how it behaves when a mechanical force is applied to it. Rheology differs from fluid dynamics in that it considers all three conventional states of matter rather than just liquids and gases. Rheological properties have far-reaching ramifications in a wide range of applications. To achieve the required flow behaviour, an additive is frequently utilised.