EP: Epoxy resin

General Properties

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EP

Epoxy resin


Epoxy resins (EP) undergo a polyaddition cross-linking reaction that does not release small molecules. The properties of the resin are strongly dependent on the structure, the degree of cross linking, type and amount of the reinforcement material and the processing procedure.

Structural Formula


Properties

Glass Transition TemperatureThe glass transition is one of the most important properties of amorphous and semi-crystalline materials, e.g., inorganic glasses, amorphous metals, polymers, pharmaceuticals and food ingredients, etc., and describes the temperature region where the mechanical properties of the materials change from hard and brittle to more soft, deformable or rubbery.Glass Transition Temperature50 to 200°C
Melting Temperatures and EnthalpiesThe enthalpy of fusion of a substance, also known as latent heat, is a measure of the energy input, typically heat, which is necessary to convert a substance from solid to liquid state. The melting point of a substance is the temperature at which it changes state from solid (crystalline) to liquid (isotropic melt).Melting Temperature-
Melting Temperatures and EnthalpiesThe enthalpy of fusion of a substance, also known as latent heat, is a measure of the energy input, typically heat, which is necessary to convert a substance from solid to liquid state. The melting point of a substance is the temperature at which it changes state from solid (crystalline) to liquid (isotropic melt).Melting Enthalpy-
Decomposition Temperature380 to 450°C
Young's Modulus3000 to 5000 MPa
Coefficient of Linear Thermal Expansion60 *10-6/K
Specific Heat Capacity1.67 to 2.10 J/(g*K)
Thermal ConductivityThermal conductivity (λ with the unit W/(m•K)) describes the transport of energy – in the form of heat – through a body of mass as the result of a temperature gradient (see fig. 1). According to the second law of thermodynamics, heat always flows in the direction of the lower temperature.Thermal Conductivity0.17 to 0.52 W/(m*K)
Density1.15 g/cm³
MorphologyThermoset
General propertiesGood toughness. Good adhesion on many substrates. Good chemical resistance. Low cure shrinkage
ProcessingCompression, spreading, injection processes such as RIM, VARI, RTM
ApplicationsBuilding industry (e.g., corrosion protection, sealings, floor coating). Boat building (construction adhesive). Electronics industry (circuit boards). Matrix for fiber-reinforced composites

NETZSCH Measurement

InstrumentDSC 204 F1 Phoenix®
Sample Mass13.22 mg
IsothermalTests at controlled and constant temperature are called isothermal.Isothermal Phase5 min
Heating/Colling Rates10 K/min
CrucibleAl, pierced lid
AtmosphereN2 (40 ml/min)

Evaluation

As an amorphous polymer, this epoxy resin exhibits a Glass Transition TemperatureThe glass transition is one of the most important properties of amorphous and semi-crystalline materials, e.g., inorganic glasses, amorphous metals, polymers, pharmaceuticals and food ingredients, etc., and describes the temperature region where the mechanical properties of the materials change from hard and brittle to more soft, deformable or rubbery.glass transition at 77°C (midpoint) with a Specific Heat Capacity (cp)Heat capacity is a material-specific physical quantity, determined by the amount of heat supplied to specimen, divided by the resulting temperature increase. The specific heat capacity is related to a unit mass of the specimen.specific heat capacity of 0.14 J/(g*K) in the 1st heating (blue) followed by an ExothermicA sample transition or a reaction is exothermic if heat is generated.exothermal effect (peak temperature 174°C), due to post-curing of the resin. As a result of the post-curing, the Glass Transition TemperatureThe glass transition is one of the most important properties of amorphous and semi-crystalline materials, e.g., inorganic glasses, amorphous metals, polymers, pharmaceuticals and food ingredients, etc., and describes the temperature region where the mechanical properties of the materials change from hard and brittle to more soft, deformable or rubbery.glass transition temperature in the 2nd heating (red) is shifted to 88°C (midpoint). The step height remains nearly the same. Since no further ExothermicA sample transition or a reaction is exothermic if heat is generated.exothermal effect occurs, it can be assumed that the epoxy resin was entirely cured during the 1st heating. Both the ExothermicA sample transition or a reaction is exothermic if heat is generated.exothermal eff ect and the position (and shift) of the Glass Transition TemperatureThe glass transition is one of the most important properties of amorphous and semi-crystalline materials, e.g., inorganic glasses, amorphous metals, polymers, pharmaceuticals and food ingredients, etc., and describes the temperature region where the mechanical properties of the materials change from hard and brittle to more soft, deformable or rubbery.glass transition temperature to higher values can be interpreted as an evidence for the degree of curing of the material.