Synthesis, Morphology, and Particle Size Control of Acidic Aqueous Polyurethane Dispersions

Area of Science:

• Polymer Chemistry
• Materials Science
• Surface Chemistry

Background:

• Aqueous polyurethane (PU) dispersions are versatile materials with tunable properties.
• Understanding the self-assembly behavior of PU chains is crucial for controlling dispersion characteristics.

Purpose of the Study:

• To synthesize and characterize charge-stabilized aqueous PU dispersions.
• To investigate the relationship between PU composition, self-assembly, and particle characteristics.

Main Methods:

• Synthesis of PU dispersions with varying compositions.
• Characterization using mass spectrometry, GPC, SAXS, AFM, and FTIR.
• Analysis of scattering data with a mass conservation model.

Main Results:

• PU dispersions form spherical particles and supramolecular structures.
• Supramolecular structure proportion increases with dimethylolpropionic acid (DMPA) content.
• Particle radius decreases with increased PU acidity, following surface charge density models.

Conclusions:

• PU particle size is governed by hydrophile (DMPA) content and polyether soft-segment molecular weight.
• A critical hydrophile coverage is required for particle stabilization, increasing with polyether molecular weight.