Cure Terms Glossary
The modulus is the ratio of stress to strain, and is a measure of a material's resistance to deformation - i.e. its stiffness. The actual modulus is specific to the strain geometry and a number of different modulus types are recognised in simple short-term testing. Examples include:
At the molecular level, modulus is a function of the stiffness of the molecule itself. Thus anything which stiffens the molecule (backbone architecture, intermolecular associations, etc.) will increase the modulus. For a hypothetical freely-jointed chain (without entanglements), the modulus is directly proportional to crosslink density and this concept has been used in the development of theories of rubber elasticity.
In oscillatory measurements,
the ratio of stress to strain gives a dynamic