Preparation and properties of high‐performance recyclable ethylene propylene diene rubber

To obtain high‐performance recyclable ethylene propylene diene rubber (EPDM), EPDM was chemically functionalized as follows: EPDM was grafted with citraconic acid (CCA) by radical melt polymerization to produce a grafted EPDM (EPDM‐g‐CCA), and EPDM‐g‐CCA was reacted with various amino acids by melt condensation reaction to give amidated copolymers (EPDM‐g‐CCA‐2‐Am, EPDM‐g‐CCA‐7‐Am, and EPDM‐g‐CCA‐12‐Am, where the n indicates the carbon number of amino acid), and then ionomers (EPDM‐g‐CCA/n‐Am/Io) were prepared by melt reaction of EPDM‐g‐CCA/n‐Ams with Zinc oxide (ZnO)/zinc stearate (ZnSt). The mechanical properties/compression set (CS) resistance (elasticity)/recyclability of pristine EPDM, EPDM‐g‐CCA, EPDM‐g‐CCA/n‐Am, and ionomers sheet samples were compared. The tensile strength/modulus, tear strength, and elasticity of samples were mostly increased in the order of ionomers>EPDM‐g‐CCA/n‐Ams>EPDM‐g‐CCA>pristine EPDM. The properties of ionomers increased significantly with increasing the carbon number in amino acid up to seven, and then levelled off or decreased a little. The tensile strength/elasticity (compression set resistance) of recyclable ionomer (EPDM‐g‐CCA/7‐Am/Io) was found to be ～9.42/～2.31 times of pristine EPDM, respectively. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42718.