Lecture
This lecture discusses the mechanical properties of polymers, focusing on their elastic deformation. The instructor begins by correlating polymer chain structure with mechanical performance, introducing concepts such as viscoelasticity and the behavior of elastomers. The lecture explains how mechanical properties are defined by a material's response to external forces, distinguishing between elastic solids and liquids. The instructor emphasizes the unique viscoelastic behavior of polymers, which exhibit both elastic and viscous characteristics depending on the applied force and duration. Various deformation types, including tension, compression, and shear, are introduced, along with methods for measuring stress and strain. The lecture also covers the significance of Young's modulus and other elastic moduli in classifying materials based on stiffness. The instructor highlights the differences between elastomers and other materials, explaining the importance of crosslinking in determining their mechanical properties. The session concludes with a preview of upcoming topics related to the rubbery state and stress-strain behavior of elastomers.