EPDM

EPDM rubber is a type of synthetic rubber, is an elastomer which is characterized by wide range of applications.

E = Ethylene,
P = Propylene,
D = diene and
M = its classification in ASTM standard D-1418.

The ethylene content is around 45% to 75%. The higher the ethylene content the higher the loading possibilities of the polymer, better mixing and extrusion. During peroxide curing these polymers give a higher crosslink density compared with their amorphous counterpart. The amorphous polymer are also excellent in processing. This is very much influenced by their molecular structure. The dienes, typically comprising between 2.5 wt% up to 12 wt% of the composition serve as crosslinks, which provide resistance to unwanted tackiness, creep or flow during end use.

Usage

An EPDM rubber roofEPDM rubber is used in vibrators and seals; glass-run channel; radiator, garden and appliance hose; tubing; washers; belts; electrical insulation, and speaker cone surrounds. It is also used as a medium for water resistance in high-voltage polymeric cable jointing installations, roofing membrane, geomembranes, rubber mechanical goods, plastic impact modification, thermoplastic, vulcanizates, as a motor oil additive, pond liner, electrical cable-jointing, RV roofs, and chainmail applications.

EPDM exhibits satisfactory compatibility with fireproof hydraulic fluids, ketones, hot and cold water, and alkalis, and unsatisfactory compatibility with most oils, gasoline, kerosene, aromatic and aliphatic hydrocarbons, halogenated solvents, and concentrated acids.

The main properties of EPDM are its outstanding heat, ozone and weather resistance. The resistance to polar substances and steam are also good. It has excellent electrical properties. It has the ability to retain light colour.

Mechanical Properties

Hardness,	Shore A 40 - 90
Tensile Strength	Ultimate 25 MPa
Density	Can be compounded from 0.90 to >2.00 gcm-³
Abrasion resistance	450 mm3
Thermal Properties
CTE	linear 68°F
	875µm/m-°C
Maximum Service Temperature	Air 100-120 °C
Minimum Service Temperature	Air -54 °C
Glass Temperature	-54 °C

Common Application

Vehicles

EPDM rubber is commonly used in weatherseals on all vehicles. This includes door seals, window seals, trunk seals, and sometimes hood seals. Frequently these seals are the source of noise due to movement of the door versus the car body. This is due to friction between the EPDM rubber and the mating surface (car painted sheet metal or glass). This can be alleviated using specialty coatings that are applied at the time of manufacture of the weatherseal, not as an aftermarket application. Such coatings can also greatly increase the chemical resistance of EPDM rubber. Some vehicle manufacturers such as General Motors also recommend a light application of silicone dielectric grease to weatherstripping to reduce noise.

Additionally, EPDM can be used as charge air tubing on turbo charged engines. More specifically, it can be used to connect the cold side of the charge air cooler(aka "intercooler") to the intake manifold.

Safety Equipment

EPDM is also commonly used as a material for the face seals of industrial respirators, most frequently chosen where the use of silicone must be avoided, typically in automotive paint spray environments.

Solar Pool Panels

Extruded EPDM is used to make a solar heat collector for swimming pool solar water heating systems.

Roofing

EPDM is used as a covering to waterproof roofs. It has the benefit that it does not pollute the runoff rainwater, which is of vital importance if the house owner wishes to use this water for personal sanitation/hygiene. Several houses equipped with rainwater harvesting thus make use of this type of roofing.

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