Introduction: Polymer blends, thermodynamics, miscibility, phase separation, and compatibilization

Abstract Although the concept blending two or more polymers is not novel, the significance of this has paved way for the invention of new high-performance materials which could make remarkable changes in the technological development. During the past few decades, a large number of important chemical and physical combinations of different polymers through random, block, and graft copolymerization methods and mixing have been developed. The scope of polymer blends to fit new market applications has quickly attracted the interests of scientists to create more development in this arena. The blending of polymers involves a lot of factors which determine their miscibility, immiscibility, and the developments of their final property. The intelligent selection of the polymers and the method is significant in developing materials with optimum performance and cost-effectiveness. The proper understanding of the determining factors like thermodynamics, phase separation, interfacial tension, blend composition, processing conditions, interfacial agents, compatibilization, viscosity, and elasticity ratio, with the support of theory, will benefit further in the progressive development of polymer blend technology. Present chapter gives a general introduction about the basic concepts of polymer blends, their classification, preparation, and properties of polymer blends in general. A detailed explanation of the morphological development of immiscible blends, and the general concept of compatibilizers and compatibilization process are also incorporated in this introductory chapter. The chapter focuses to serve as a basic chapter for a deeper and clearer understanding of the other chapters included in this book.