POLYMERS

Curing of an Epoxy Resin

Analysis and optimization of thermosets can easily be carried out using differential scanning calorimetry.

Presented here is the DSC 300 Caliris® measurement on an epoxy resin. The uncured epoxy resin was heated up from -60°C to 250°C (green curve). As a first effect 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 of the uncured material was observed at -34°C. The ExothermicA sample transition or a reaction is exothermic if heat is generated.exothermic peak detected at 112°C (peak temperature) during the 1st heating is caused by Curing (Crosslinking Reactions)Literally translated, the term “crosslinking“ means “cross networking”. In the chemical context, it is used for reactions in which molecules are linked together by introducing covalent bonds and forming three-dimensional networks.curing of the sample. After this first heating to 250°C, the epoxy resin is completely cured. 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 of the cured sample can be determined by means of a second heating (blue curve): it was detected at 123.7°C (midpoint).

DSC measurements on an epoxy resin. Sample mass: 9.00 mg; crucibles: Concavus® Al crucible with lid; temperature program: 1st heating green curve, 2nd heating: blue curve; heating rate: 10 K/min