to Polymers
Dr. Dmitri Kopeliovich
Thermosets are Polymers which do not melt when heated.
Thermosets molecules are cross-linked by strong covalent intermolecular bonds, forming one giant molecule.
Cross-linking is irreversible therefore thermosets can not be reprocessed (re-melt).
Cross-linking is achieved in curing process initiated by heat, chemical agents or radiation.
Before curing processing thermoset materials are stored in partially polymerized condition.
Vulcanization (cross-linking, curing) results in sharp increase of strength, elasticity and stability of thermosets.
Thermosets are stronger and stiffer than Thermoplastics. Stiffness of thermosets is even higher than some metals (aluminum).
Thermosets also have higher thermal, chemical and creep resistance than thermoplastics.
Thermoset materials may contain filler materials in form of powder or fibers, providing improvement of specific material properties (strength, stiffness, Modulus of Elasticity, thermal resistance, lubricity).
Common filler materials are glass in various forms, metal powders, Graphite or molybdenum disulfide powder.
Thermoset groups:
to Polymers