EPDM polymers with intermolecular asymmetrical molecular weight, crystallinity and diene distribution

Conference · Fri Dec 31 04:00:00 EST 1993

OSTI ID:141948

Datta, S; Cheremishinoff, N P; Kresge, E N ^[1]

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1. Exxon Chemical Co., Linden, NJ (United States)

Rapid extrusion of EPDM elastomers require low viscosity and thus low molecular weights for the polymer. Efficient vulcanization of these elastomers requires network perfection and thus high molecular weights for the polymer. The benefits of these apparently mutually exclusive goals is important in uses of EPDM elastomers which require extrusion of profiles which are later cured. This paper shows that by introducing simultaneously asymmetry in the distribution of molecular weights, crystallinity and vulcanizable sites these apparently contradictory goals can be resolved. While these polymers cannot be made from a single Ziegler polymerization catalyst, the authors show the synthesis of these model EPDM polymers by blending polymers with very different molecular weights, ethylene and ENB contents. These blends can be rapidly extruded without melt fracture and can be cured to vulcanizates which have excellent tensile properties.

• OSTI ID: 141948
• Report Number(s): CONF-930304--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
40 CHEMISTRY
CHEMICAL COMPOSITION
CRYSTAL STRUCTURE
ETHYLENE PROPYLENE DIENE POLYMERS
EXTRUSION
MOLECULAR WEIGHT
STRUCTURAL CHEMICAL ANALYSIS
VULCANIZED ELASTOMERS
ZIEGLER CATALYST