Enhancements of clay exfoliation in polymer nanocomposites using a chemical blowing agent

A novel approach, via the use of a blowing agent (BA), to enhance clay exfoliation in polymer nanocomposites is reported. A commercial organoclay was treated with a common low-cost BA, which was then melt-processed with polymers in an extruder. The characterization results revealed that the degrees of exfoliation of the clay were increased when using BA. Consequently, the resultant nanocomposites exhibited improvements in thermal degradation temperature as compared to their corresponding polymers and nanocomposites without the involvement of BA. They also presented simultaneous improvements in stiffness, strength, ductility and toughness. These property enhancements were mainly attributed to the presence of BA in clay interlayers which degraded during melt compounding, generated gases and pushed clay layers apart, facilitating clay exfoliation under the shear forces. This work demonstrates the potential of using a BA to produce high-performance polymer/clay nanocomposites by melt processing.