Gassing The propensity of a material to form a gas during cure.
Gel Time The time it will take a thermosetting material to become solid at a given temperature and mass.
Glass Transition Temperature (Tg) The temperature at which cured resins undergo a change from a glassy state to a softer more rubbery state.
Hardener
A material or mixture of substances added to a plastic composition which cross links another material, typically a polymer. See Curing Agent.
Hardness
Resistance of a material to deformation by indentation. See Shore Hardness.
Heat Deflection Temperature
HTD - The temperature at which a standard test bar will deflect 0.010" under a static load of 264 psi. A method to approximate Tg.
Impact Strength
The ability to withstand shock loading; or, work required to fracture under shock loading a specified test specimen in a specified manner. See IZOD Impact Strength.
Impregnate
To fill the voids of a material with a compound.
Insulation Resistance
The ratio of the direct voltage applied to electrodes in contact with an epoxy system to the total current between them. It is dependent upon both the volume and surface resistance of the epoxy systems. ASTM D257-61.
Izod Impact Strength
The amount of force necessary to fracture a notched piece of plastic with a hammer type impact. Measured in foot pounds/inch of notch. Also known as the brittleness of a material. Brittle materials will have low izod impact values (.15 for example). Tough materials will have high izod impact strengths (.60 for example).
