Newly designed diblock dispersant for powder stabilization in water-based suspensions

Area of Science:

• Materials Science
• Colloid and Surface Chemistry
• Polymer Science

Background:

• Effective dispersion of powders in water-based suspensions is crucial for various industrial applications.
• Commercial dispersants like ammonium polyacrylate (PAA-NH4) have limitations in achieving optimal dispersion efficiency and stability.
• The development of novel dispersants with enhanced properties is an ongoing area of research.

Purpose of the Study:

• To introduce and evaluate a newly designed dispersant, ammonium poly(methacrylate)-block-poly(2-phenoxyethyl acrylate) (PMA-b-PBEA), for water-based suspensions.
• To compare the dispersion efficiency of PMA-b-PBEA with a commercially available dispersant, PAA-NH4.
• To elucidate the structure-property relationships governing the performance of PMA-b-PBEA.

Main Methods:

• Rheological analysis was employed to assess the dispersion efficiency and stability of the suspensions.
• Adsorption studies were conducted to quantify the interaction between the dispersant and the powder surface.
• Derjaquin-Landau-Verwey-Overbeek (DLVO) calculations were utilized to determine stabilization energies.

Main Results:

• The newly designed dispersant PMA-b-PBEA demonstrated superior dispersion efficiency compared to PAA-NH4.
• The diblock structure of PMA-b-PBEA, featuring both anchoring and stabilizing moieties, is key to its high performance.
• PMA-b-PBEA exhibited approximately double the adsorption of PAA-NH4 and generated fewer counter-ions, leading to enhanced steric and electrostatic stabilization.
• Excellent dispersity was achieved for titania (TiO2) powders in suspensions with 60wt% solid content, without rheological hysteresis.

Conclusions:

• PMA-b-PBEA is a highly effective dispersant for water-based suspensions, outperforming conventional alternatives.
• The unique diblock copolymer architecture of PMA-b-PBEA is responsible for its superior adsorption and stabilization capabilities.
• This novel dispersant offers significant potential for applications requiring stable, high-solid content suspensions, such as in advanced materials processing.