Molecular Structure and Processing Characteristics of Metallocene EPDM Rubbers

Abstract We report the molecular structure and processing characteristics of a series of metallocene-based EPDM rubbers. The relationships between molecular weight and composition distributions and the ENB content of the polymers, and their effects on network structure development are investigated. Experimental data and Monte Carlo simulation results reveal that, compared to EPDM of broad MWD, EPDM rubbers with narrow MWD can achieve faster cure and higher degree of cure at equal or lower ENB level during vulcanization. The processing behaviors and mechanical properties of rubber compositions and formed articles based on EPDM grades of different manufacturing technologies are evaluated. The combination of high MW and narrow MWD of the metallocene EPDM polymers enables fast cure rate, high cure efficiency, and improved scorch safety during processing, and good mechanical strength of fabricated articles of the formulations. Specific examples will be given in the paper.