Epoxy Resins and Compounds Terminology
- Exotherm
-
Exotherm is the heat generated during the chemical reaction between a resin and hardener. These exotherms are dependent of mass and surface are. If a very large mass exotherms, it may result in a runaway reaction where the heat generated will cause thermal decomposition of the resin. Epoxy systems tend to exotherm more than urethanes and unfilled systems more than filled.
Back To Top - Fire Resistant
-
Treated as to be nonflammable.
Back To Top - Fire Retardant
-
Having the ability or tendency to slow or stop the spread of fire.
Back To Top - Flexural Strength
-
Flexural strength is also known as the force required to break a material while bending. Flexural strength is measured in terms of stress, and thus is expressed in pascals (Pa) in the SI system.
Epic uses test method ASTM D790.
Back To Top - Gel time
-
The point in time after mixing a two component material, or heating a one component material to its cure temperature, at which the material ceases to flow. The material will change from a flowable liquid to a continuous mass at this point.
Epic uses test method ASTM D3056.
Back To Top - Glass Transition Temperature
-
The glass transition temperature, Tg, is the temperature at which a thermoset polymer changes from a glassy solid to an elastomer and back. Many physical and electrical properties of a material will change drastically before and after this transition.
Epic uses test method ASTM E1545 (sometimes E1356).
Back To Top - Hardness
-
Hardness, or Shore Hardness, is a measure of a material's hardness to arbitrary standard values.
We measure hardness with Shore hardness gauges. These gauges impress a point into a surface under spring load. The gauge measures the resistance to the point's penetration. Harder materials are usually measured with a Shore Type "D" gauge, softer materials with a Shore Type "A" gauge, and very soft materials with a Shore Type "OO" gauge. See also “Durometer”.
Epic uses test method ASTM D2240.
Back To Top - High Tear Strength
-
High tear strength (or tear resistance) is a measure of how well a material can withstand the effects of tearing.
Back To Top - Hydrolytic Stability
-
Hydrolytic stability is a hydraulic fluid's capacity to withstand and resist chemical decomposition when exposed to water. Because water is one of the most common contaminants that a hydraulic fluid will regularly come into contact with, hydrolytic stability is an important characteristic.
Back To Top - Izod Impact Test
-
Izod impact strength is an ASTM standard method of determining impact strength. A notched sample is generally used to determine impact strength.
Back To Top - Lap Shear Strength
-
Lap Shear strength is the ability of an adhesive to resist forces that cause the material to adhere to substrates. Shear strength is measured in a tensile test and is measured in pounds per square inch, based on the area of the sheared edge. The shear strength of a structural adhesive is the maximum shear stress in the adhesive before failing under tensile loading.
Epic uses test method ASTM D1002.
Back To Top - Linear Shrinkage/Shrinkage
-
All thermoset materials shrink as they cure. The source of this shrinkage is three-fold. First, thermoset materials tend to exotherm, or heat up as they cure. The materials flow into their final shape as a liquid that is warm and then set to a solid while warm. Upon cooling back to room temperature, the solid goes through normal contraction experienced by solids as they cool. This results in a part that is smaller than the mold or part it was originally poured into.
A second source of shrinkage in thermoset materials is due to the molecular reorganization that results in the cure of the thermoset material. When a mixture of molecules reacts chemically into a single, new molecule, the distances between atoms are reduced. This decrease in molecular length results in shrinkage.
Third, in general, liquids are less dense than solids. A thermoset material begins as a lower density liquid and ends as a higher density solid. This change in density results in shrinkage.
Linear shrinkage specifically refers to the change in length of an extended volume of thermoset material on cure.
Higher exotherm materials like rigid epoxies tend to shrink more than softer ones like urethanes. Filled materials display less shrinkage than unfilled ones.
Back To Top - Low VOC
-
Low VOC materials have reduced amounts of volatile organic compounds.
Back To Top - Mitigating Thermal Runaway
-
Mitigating thermal runaway is to slow a phenomenon with lithium-ion batteries, in which the lithium-ion cell enters an uncontrollable, self-heating state. Thermal runaway can lead to the ejection of gas, shrapnel, or other particulates. Effective methods of mitigating thermal runaway include thermal insulation and reinforced heat dissipation.
Back To Top - Modulus
-
Modulus is the stress verses strain relationship for a material. In general, a high modulus material tends to be rigid where a low modulus one would be elastomeric like a rubber band.
Epic uses test method ASTM D638/D412 tensile, D790 flexural, D695 compressive.
Back To Top - Outgassing
-
The release of trapped gas or vapors previously dissolved, trapped, frozen, or absorbed in a solid.
Back To Top - Polybutadiene
-
A synthetic rubber formed from the polymerization of monomer 1, 3-butadiene. Polybutadiene has high resistance to wear.
Back To Top - Polymer
-
Any class of natural or synthetic substances composed of large molecules called macromolecules. Macromolecules are multiples of simpler chemical units called monomers.
Back To Top - Polyurethane
-
Polyurethane is a class of polymers composed of organic units joined by urethane links.
Back To Top - Pot Life
-
The length of time that a catalyzed resin system retains a viscosity low enough to be used in processing.
Back To Top