Managing Ionic Strength for Long-Term EVA–PU Stability

Ionic strength is underestimated factors in waterborne formulation stability. Unlike pH, it is not always measured directly, yet it strongly influences particle interactions.

In EVA–PU systems, every formulation component contributes to ionic strength: neutralizers, dispersants, surfactants, preservatives, and functional additives. While each addition may seem insignificant, their combined effect can destabilize the system over time.

High ionic strength compresses the electrical double layer around anionic PU particles, reducing repulsive forces and increasing the likelihood of aggregation. This explains why many EVA–PU blends appear stable initially but fail after extended storage.

Reducing unnecessary ionic additives, using nonionic alternatives where possible, and introducing compatibility buffers can significantly improve long-term stability. These measures help maintain a balance between electrostatic and steric stabilization mechanisms.

Designing formulations with ionic strength in mind is essential for systems intended for industrial storage and transport.

[email protected]