Fitted Classical Nucleation model

The fitted classical nucleation model describes the nucleation rate, that is, the number of bubbles generated during a thermoplastics microcellular molding process, per unit volume and time.

The following equation describes the fitted classical nucleation model:

where:

• is the nucleation rate (/m³s)
• is Avogadro's number (mol^-1)
• is molecular mass of the gas molecule (kg)
• is the surface tension (N/m)
• is Boltzmann's constant (J/K)
• is the temperature (K)
• is the gas pressure in the resin prior to bubble nucleation (Pa)
• is the polymer resin pressure (Pa)
• is a fitting parameter (correction factor of the Zeldovich factor)
• is a correction factor of the free energy barrier of bubble nucleation

and and are determined by fitting nucleation data obtained from a molding experiment.

Note: The effect of shear/extensional stress on nucleation is not considered in this model.