Influence of compression speed and deformation percentage on mechanical properties of calcium alginate particles

Abstract

Hydrogel particles are often used as carriers for the immobilization of enzymes, polyphenolic antioxidants, whole microbial, plant or mammalian cells. In many processes, the mechanical properties of alginate particles are essential due to their exposure to mechanical forces in production process. Determination and improvement of hydrogels mechanical properties is very important in prevention of the undesirable side effects during the manufacturing process and product application. The aim of this study was to define the mechanical properties of single particles submerged in water and in dry conditions using the compression method between two flat surfaces. The results indicated that the formulation of alginate beads and water loss during compression have significant influence on their mechanical behavior and stiffness. Calcium-alginate particles were produced using an electrostatic droplet extrusion technique, with an initial sodium alginate concentration of 1.5%, w/V, and calcium chloride (2.0%, w/V) as the gelling solution. The research findings were used to determine the influence of working conditions, sample deformation (10-50%) and different compression speeds (1-50 mm/min) on the mechanical strength of alginate beads. The Young’s moduli and maximal forces for investigated deformation percentage of the alginate particles were determined from generated force-displacement and stress-strain curves during compression.