Tailoring Polymer Molecular Structure in the EPDM Slurry Process

摘要

EPDM is the most extensively used elastomer in non-tire applications, and still shows growth potential in a mature rubber market Although, EPDM has been in existence for quite some time, the technology is constantly evolving to meet aggressive market demands. Different production processes produce EPDM, and therefore, careful engineering of polymer micro- and macro- structures is necessary to meet the desired performance characteristics. This paper highlights the process capability of the EPDM slurry technology to tailor and control the molecular structural design. The catalyst and the polymerization technology produce EPDMs with a wide spectrum of chemical composition and Mooney viscosity. The relatively narrow molecular weight distribution of the polymers has been designed to offer the best combination of processing and physical properties. A unique technology for the incorporation of long chain branching in the polymer has been developed. This highly selective catalyst technology controls the degree of branching and molecular weight distribution without any side reaction, while offering the flexibility to vary polymer composition and molecular weight. The EPDMs made with the modified molecular structure have a good balance of processing and performance characteristics.