Quantifying effects of particulate properties on powder flow properties using a ring shear tester

Area of Science:

• Materials Science
• Pharmaceutical Engineering
• Powder Technology

Background:

• Powder flow is critical in pharmaceutical manufacturing.
• Understanding factors influencing powder flow is essential for process optimization.

Purpose of the Study:

• To investigate the impact of particle size, morphology, density, and surface silicification on powder flow properties.
• To quantify powder flow using the flow function (FF) and unconfined yield strength.

Main Methods:

• Utilized a ring shear tester to evaluate 11 different microcrystalline cellulose (MCC) powders.
• Analyzed powders including Avicel (regular MCC), Prosolv (silicified MCC), and Celphere (spherical MCC).
• Quantified powder flow by measuring unconfined yield strength as a function of major principal stress.

Main Results:

• Smaller particle size consistently resulted in poorer powder flow properties.
• Spherical particle morphology (Celphere) significantly improved flow compared to elongated particles (Avicel).
• Higher particle density correlated with better flow behavior, and surface silicification enhanced flow in finer MCC.

Conclusions:

• Particle size, morphology, and density are key determinants of powder flowability.
• Surface area and particle shape play significant roles in powder consolidation and flow.
• Surface silicification offers benefits for fine powders, improving their handling characteristics.