Topic summary
Glass transition temperature
Extracted from the Wikipedia article Glass transition.
Effect of polymer blending on glass transition
On the other hand, for miscible polymer blends in which the individual polymers mix favorably and completely, there is a single glass transition temperature which is typical in between the glass transition temperatures of the individual polymer Tg values. However, the glass transition temperature of the doesn't always have to be in between the individual Tg values. The glass transition temperature of the miscible polymer blend is influenced by the composition and individual Tg values of the polymers. The flory-fox equation/ model can be used to estimate the glass transition temperature of a miscible polymer blend to a good degree of accuracy when there are strong interactions between the individual polymers. The fox model assumes that the mixing is ideal and that the chains are fully interspersed, which is why it only works accurately when there are strong interactions between the individual polymers. The equation below describes the Fox equation where w is the weight fraction of the individual polymer and Tg represents the glass transition temperature.