Theoretical Model of Polymer Network Chain Formation under Strain

Area of Science:

• Polymer Science
• Materials Science
• Chemical Engineering

Background:

• Polymer network chain formation is crucial for material properties.
• Existing models like the classical two-network model have limitations in explaining complex reaction dynamics.
• Understanding the influence of cross-linking and scission on free energy is essential for accurate polymer modeling.

Purpose of the Study:

• To investigate polymer network chain formation under multiple strain stages.
• To clarify the effects of various chemical reactions (cross-linking, scission) on network free energy.
• To generalize the classical two-network model by incorporating these reaction dynamics.

Main Methods:

• Utilizing the thermal fluctuation principle to study polymer network chain formation.
• Developing a new constitutive model based on affine deformation theory.
• Deriving a free energy change expression associated with reaction sequences under strain.
• Avoiding the need for independent network hypothesis and stress-transfer functions.

Main Results:

• A novel constitutive expression for network chains formed under two strain stages was derived.
• The model successfully accounts for the free energy changes due to specific reaction sequences.
• The proposed model demonstrates higher precision compared to the classical two-network model.

Conclusions:

• The developed model provides a more accurate description of polymer network behavior under strain.
• It offers a generalized approach to understanding polymer chain dynamics influenced by chemical reactions.
• The findings are validated by experimental data on silicone elastomers, showing improved predictive power.