THE DEFORMATION OF MICROSCOPIC GEL PARTICLES

This paper describes an investigation of the behaviour of individual ' 'Sephadex'' particles supplied by Pharmacia Biotech ( a cross-linked h ydrogel with diameter range between ca. 60 and 600 mu m) under uniaxia l compression between parallel plates. Experimental procedures for obt aining the loading-unloading and the stress relaxation characteristics are described. A first order analytical solution, based upon the Hert z theory, for the elastic modulus of the particles is presented and di scussed for different cases. The various potential mechanisms for the observed stress relaxation behaviour of these systems are described an d evaluated.