Silicone-Based Polymer Blends: An Overview of the Materials and Processes

Although extensive studies on copolymers have been carried out with a view to exploiting thecombined homopolymer properties, physical blends of polymers have warranted less attention. But as a resultof increased scientific and economic interest research in this challenging field has grown over the lasttwo decades. The unique properties of silicone polymers, due to their Si–O–Si backbone, includingtheir low Tg's, gives rise to some specific applications. However, it is their singular structure whichalso makes silicone polymers incompatible with most other macromolecules and limits their incorporationto low amounts. Bleeding and mechanical loss are observed at higher percentages. This overview is dividedinto three parts: the first covers silicone/polymer bicomponent blends with the silicone being either functionalizedor not. The second part describes the different ways to compatibilize the two phases of the silicon/polymerblend using copolymers which can be added as either preformed copolymers or synthesized in-situ. The efficiencyof the copolymers involved varies depending on their chemical structure and architecture. The final sectionis dedicated to the different methods of preparation of Interpenetrating Polymer Networks (IPNs) which arecommercially and industrially by far the most interesting. The relevant processes (extrusion, batch, casting,etc.) as well as the properties of the various resulting materials are also reviewed throughout the paper.