Ethylene-Propylene-Diene Terpolymer/Halloysite Nanocomposites: Thermal, Mechanical Properties, and Foam Processing

Ethylene-propylene-diene terpolymer (EPDM)/halloysite nanotube (HNT) nanocomposites were prepared by melt mixing in an internal mixer using a commercially available maleated semicrystalline EPDM and HNT. Transmission electron microscopy analysis of the EPDM/HNT composites revealed that the HNTs are uniformly dispersed at a nanometer scale in the matrix. Differential scanning calorimeter studies indicated that the HNT caused an increase in the nonisothermal crystallization temperature of the EPDM. Tensile and dynamic mechanical analysis exhibited that a small amount of the HNTs effectively enhanced the stiffness of the EPDM without adversely affecting its elongation-at-break. The EPDM/HNT nanocomposites were used to produce foams by using a batch process in an autoclave, with supercritical carbon dioxide as a foaming agent. The nanocomposite foams showed a smaller cell size and higher cell density as compared to the neat EPDM foam, and the nanocomposite with 10 phr HNT produced a microcellular foam with average cell size as small as 7.8 m and cell density as high as 1.5 x 10(10) cell/cm(3). (c) 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40307.