Polymer is a substance which has a molecular structure built up chiefly or completely from a large number of similar units bonded together, e.g. many synthetic organic materials used as plastics and resins. To understand the miscibility of polymers characteristics of blends and mechanism of toughening the basic concepts of polymer blends will be clearly understood.to infer the thermodynamic of polymer-polymer miscibility.to classify the types of polymer blends.to interpret the characterized polymer blends.to discover the application of polymer blends.