Glass transition temperature in polymer blends

Abstract The Couchman equation for miscible blends has been extended. The new semiempirical equation, w 1 ln ( T g / T g1 ) + kw 2 ln ( T g / T g2 ) = 0, is simple to use and flexible enough to provide an adequate description of T g variation with composition for miscible, semimiscible, and immiscible blends. The equation parameter k indicates the blend miscibility.