Ethylene–Propylene–Diene Rubber

Abstract

EPM and EPDM are the fastest growing elastomers by virtue of their excellent ozone resistnce in comparison with commodity rubbers. Even though these rubbers have been commercially available for more than 30 years, the production and applications technologies are still very much under development. The various structural parameters of EP(D)M are described, as well as how these depend on production conditions. EP(D)M is produced in suspension with liquid propylene as dispersing agent, or most commonly in solution where the polymer produced is dissolved in a hydrocarbon solvent. The solution process technology is described in detail. EP(D)M can be compounded with fillers and plasticizers. Basic principles of compounding are described, including a few typical examples of EP(D)M recipes. EP(D)M can be mixed, extruded, and vulcanized on all common rubber‐factory equipment. The mechanical properties depend considerably on the structural characteristics of the EP(D)M and the type and amount of fillers in the compound. Some typical properties of EP(D)M vulcanizates are good elastic properties, resistance to heat and ozone, various chemicals, and good electrical properties. The principal uses of vulcanized EP(D)M rubber are in automotive, building and construction, cable and wire, and appliances. Unvulcanized EP(D)M rubber is mainly used in blends with thermoplastics, particularly polypropylene, and as an oil additive.

Synthesis, Structure, and 1-Hexene Polymerization Catalytic Ability of Group 5 Metal Complexes Incorporating an [OSSO]-Type Ligand

“…In both academia and industry, significant efforts have been made in achieving highly active homogeneous catalysts and stereospecific polymerization. − Accordingly, numerous metallocene and postmetallocene group 4 metal catalysts have shown powerful catalytic activity and complete stereospecificity for α-olefin polymerization . In contrast, only a few examples of successful α-olefin polymerization catalyzed by group 5 metal complexes have been published. − Vanadium-based heterogeneous polymerization systems first appeared in the 1950s and achieved notable success in the production of ethylene–propylene and ethylene–propylene–diene elastomers. , Vanadium precatalysts bearing chelating aryloxides have been shown by several research groups to be highly active polymerization catalysts for ethylene or ethylene–propylene . Recently, researchers reported tantalum complexes as olefin copolymerization catalysts. , For example, Fujita and co-workers synthesized tantalum complexes bearing tris­(pyrazolyl)­borate ligands (Tp) and showed that, when activated with dried methylaluminoxane (dMAO) or i Bu 3 Al/(Ph 3 C)­[B­(C 6 F 5 ) 4 ], these complexes were active ethylene polymerization catalysts that produced low- to high-molecular-weight polyethylene with relatively narrow to broad molecular-weight distributions .…”

Experimental Validation of the Charlesby and Horikx Models Applied to De-Vulcanization of Sulfur and Peroxide Vulcanizates of Nr and Epdm

“…42 For EPDM it is well known that due to side-reactions via the unsaturated third monomers ethylidene norbornene and less so hexadiene, commonly a substantial amount of branching is obtained during polymerization, which definitely also disturbs the molecular mass distribution. 43 In addition, a distribution skewed to low molecular masses is quite common. Therefore, to investigate the influence of the molecular mass distribution, three polymers that strongly differ in their distributions were used in the present study.…”