General Characteristics of Common Polymers

Ethylene Propylene is a polymer with outstanding properties. It has exceptionally good weather aging and ozone resistance; excellent water and chemical resistance; excellent resistance to gas permeability and excellent resistance to aging due to exposure to steam; and heat resistance excellent up to 350°F. Ethylene Propylene is a polymer where oil and solvent resistance is poor, however, it is fairly good in ketones and alcohols.

Ethylene Propylene is not recommended for food applications or exposure to aromatic hydrcarbons.

Fluorosilicone is considerably more expensive than silicone, however it is developed for special applications where general resistance to oxidizing chemical, aromatic and chlorinated solvent bases is required.

Fluorosilicone is not recommended and is generally attacked when exposed to brake fluids, hydrazine and ketones. Fluorosilicone should not be confused with silicone in regard to high heat resistance.

Natural Rubber has many good characteristics. It has high resilience, good compression set, food roll building behavior, and molding properties; very good friction surface, but not a fine smooth surface when ground; high tear strength, low crack growth; usable for ketones and alcohol; and good low temperature properties.

Natural Rubber is not recommended for oil and solvent resistance and ozone attacks it.

The castable types have excellent abrasion resistance; good compression set at high hardness levels; low friction surface; tensile strengths up to 6000 PSI; good ozone resistance; good oil and solvent resistance; and poor heat and hot water resistance. The millable types of Polyurethane are in wide use today. Through the use of reinforcing pigments and other chemicals, desirable characteristics can be obtained to fit a variety of applications: wear resistance is excellent and greatly superior to most other polymers; the surface is of low friction nature; oil resistance is good and equivalent to the better nitriles but is not recommended for use in water or heat above 175°F; plus good ozone resistance and low rebound characteristcs.

Urethane is not normally attacked by moderate chemicals and hydrocarbons. It is generally attacked by concentrated acids, ketones, chlorinated and nitro hydrocarbons.

Epichlorohydrin is an outstanding polymer, exhibiting most of the better qualities of nitrile and neoprene, but having additional plus features: oil and solvent resistance is very good. Hydrin has especially low swell in gasoline; low temperature performance is better than either nitrile or neoprene, and offers less torsional stiffness at sub zero temperatures; high temperature endurance is good up to 250°F; resilience is good and compression set is fairly good in many compounds; abrasion is equivalent to the nitriles; and ozone weathering and water resistance are very good.

Epichlorohydrin is generally attacked by ketones, esters, aldehydes, chlorinated and nitro hydrocarbons.