2018 Volume 91 Issue 4 Pages 115-120
Herein we investigate the molecular structures of EPDMs derived from different catalyst technologies and their effect on performance with automotive weather sealing profile extrusion as target application. Dow’s recent development of advanced molecular catalysts (AMC) enables new molecular design capabilities to surpass the performance of the previous generation of single site constrain geometry catalyst (CGC) EPDMs. New capabilities entail higher molecular weight, broader molecular weight distribution, more homogeneous long chain branching and higher diene content. All these polymer attributes were thought to be associated only with Ziegler-Natta (ZN) catalyzed EPDMs till now, however, a new EPDM (EPDM-AMC) is characterized by these attributes and has been specifically designed for fast dense extrusion processes. It’s molecular geometry anticipates high performance during processing (green strength, curing speed). As a final part the performance of EPDMs derived via three types of catalyst, namely AMC, CGC, and ZN are compared.
