Glossary

“B” Stage: an intermediate stage during the curing process when the material has gelled and hardened, but has not reached fully cured properties, the material may need additional post-curing

adhesive failure: the inability of an adhesive to stick to a surface or substrate, the adhesive cannot bind two surfaces together and separates from one or both substrates

arc resistance: the time required for a material exposed to an electrical arc to become electrically conductive

cast: a solid formed by pouring a liquid that hardens into the shape of a mold

catalyst: a material that initiates or accelerates the chemical reaction during the curing process

Coefficient of Thermal Expansion (CTE): the rate at which a material expands or contracts across a range of temperatures

cohesive failure: the inability of an adhesive to resist internal seperation, the material sticks to the two substrates, but seperates in the middle

co-polymer: a polymer formed by chemicaly combining two or more monopolymers

cross-linking: the bonds that link polymer chains together, for our purpose, these bonds give the polymers their cured physical properties

cure cycle: the amount of time and temperature that is necessary for the material to reach it’s optimum properties

cure time: the time necessary for materials to reach certain properties, can vary with temperature

Density: weight per unit of volume for a material

dielectric constant: ratio of capacitance, or it’s ability to conduct electricity, of a material to the capacitance of air

dielectric strength: the maximum electrical voltage a material can withstand without breaking down

dissipation factor: the rate that energy is lost from a dielectric material, usually in the form of heat

elongation: a measurement used to determine how much a material will stretch in the presence of tension, meausred as a percentage increase over the unstretched material

encapsulating: completely enclosing a component within another material

exotherm: heat that is given off during a reaction

filler: inert solid particles that are added to a liquid material to enhance or change certain properties

flexual strength: how strong a material is in the presence of lateral forces that cause bending

gel time: the time it takes for a thermosetting liquid to become a solid

Glass Transition Temperature (Tg): the temperature at which a material passes from a soft rubbery state into a solid, rigid state

Green Strength: the grabbiness or tackiness of a material, the ability of an adhesive to hold two materials together when first contacted

heat deflection temperature: the temperature at which a standard bar test will deflect 0.010″ under a static load of 264 psi

impact strength: how well a material can withstand sudden impacts or shock loading

izod impact strength: a measurement of the force necessary for a notched piece of plastic to be fractured by a hammer type force

lap shear strength: a test used to determine adhesion to two different surfaces in which two substrates are first glued together using an adhesive, and then pulled apart laterally without peeling

Meter Mix Dispense Equipment (MMD): a type of equipment used to process plural component materials cleanly and efficiently

Mix Ratio: the stoichiometric ratio at which plural component materials are to be mixed

modulus of elasticity: a measure of how much a material is deformed under stress

moisture absorption: how moisture is absorbed into a material under certain conditions

moisture resistance: a material’s ability to resist moisture absorption

post cure: when a material is heated after it’s initial reaction in order to enhance certain physical and chemical properties

pot life: the amount of time 2 thermosetting liquids may be easily used after mixing, this is also the amount of time it takes for the viscosity of a material to double

release agent: a chemical agent used to prevent a material from sticking to surfaces

Shore Hardness: a test method used to determine how hard a material is. Values are recorded using a letter and a number. The lower the number, the softer the material. The scale ranges from extremely soft (Shore 00) to extremely rigid and hard (shore D)

solvent: a liquid in which other materials are dissolved

Specific Gravity: a ratio used to express density against a reference material, in our case, water

surface resistivity: a number used to express the insulating properties of a material, it is the resistance of a material to the flow of electricity across it’s surface

tensile strength: the amount of pulling force required to break a material

thermal conductivity: a measure of a material’s ability to conduct heat

thermoplastic: a polymer that repeatedly becomes pliable above a certain temperature

thermoset: a polymer material that irreversibly cures through a chemical reaction, it will no longer become pliable above certain temperatures

thixotropy: the property of a liquid that describes how pasty or viscous a material is. A material with high thixotropy will exhibit non-sagging and non-flowing properties

viscosity: the meausure of a liquid’s thickness, or resistance to flow

volume resistivity: the resistance of a material to the flow of electric current through itself, as opposed to along it’s surface

water absorption: a test method used to determine how much moisture a material will absorb under certain conditions

work life: the time it takes for a liquid’s viscosity to increase to a point where it is no longer easy to work with