The glass transition temperature Tg of polyvinyl chloride PVC is typically around 80C 176F , although it can vary depending on the specific formulation and presence of additives. The glass transition temperature is the temperature at which a polymer changes from a glassy, brittle state to a rubbery, more flexible state. At temperatures below the Tg, PVC is in its glassy state and exhibits relatively high stiffness, low elongation, and low impact resistance. In this state, the polymer chains have limited mobility, and the material is more prone to cracking or breaking under stress.As the temperature increases above the Tg, PVC transitions to its rubbery state, where the polymer chains have increased mobility. In this state, PVC exhibits improved flexibility, higher elongation, and better impact resistance. However, the stiffness and tensile strength of the material decrease as the temperature increases above the Tg.In practical applications, understanding the glass transition temperature of PVC is crucial for determining its suitability for specific uses. For example, PVC used in outdoor applications may need to have a higher Tg to withstand temperature fluctuations and maintain its mechanical properties. In contrast, PVC used in flexible applications, such as hoses or cable insulation, may require a lower Tg to ensure adequate flexibility and durability.Additives, such as plasticizers, can be used to modify the Tg of PVC to tailor its mechanical properties for specific applications. Plasticizers increase the distance between polymer chains, allowing for greater mobility and flexibility at lower temperatures. This results in a lower Tg and a more flexible material.