Physical Properties of Polymer/Clay Nanocomposites
This chapter presents the physical properties of polymer/clay nanocomposites. The discussion will attempt to cover the engineering, barrier, and flame retardancy characteristics of polymer/clay nanocomposites and will be divided broadly into thermoplastics, thermosets, and rubbers. The engineering properties of polymer/clay nanocomposites in general exhibit substantial improvement in tensile strength, tensile modulus, flexural strength and modulus, heat distortion temperature, and in ideal cases no loss in impact strength. The physical properties of a number of other polymer nanocomposites made with clays have been measured. In general the most critical factor that governs the ultimate improvement in engineering properties in polymer/clay nanocomposites is the level of exfoliation. The flammability of polymers in many applications is of critical importance. Based upon many studies conducted on the flame retardancy of polymer/clay nanocomposites it appears that clay addition to a polymer system will improve its flame retardancy substantially. In many applications the gas barrier properties of polymers is critical. This is especially true in a food packaging industry. Effect of aspect ratio and clay loading on relative gas permeability of the composite is illustrated. There has been a considerable amount of work conducted on thermoset resin/clay nanocomposites. The overall trends seen in thermoplastics concerning engineering, flammability, and barrier properties are also seen in thermosets. Rubber is an important worldwide commodity. The worldwide consumption can be divided into natural and synthetic. This chapter will divide the advancements in rubber nanocomposites as a function of polymer type.