ELASTIC PROPERTIES OF FLOCCULATED NETWORKS

The dependence of the shear modulus G prime on the volume fraction phi was measured for volume-filling networks formed by Brownian flocculation of aqueous polystyrene latices. The effect of frequency on G prime was slight and the response remained linear for strains as large as approximately 5%. We found G prime approximately phi **n with n equals 2. 5 for freshly flocculated samples and n equals 4. 4 for aged samples. The authors' measurements indicate predominantly elastic behavior of networks formed by Brownian flocculation of polystyrene latices. The response remains linear at strains below about 5% and remains nearly independent of frequency. The shear modulus depends strongly on volume fraction and somewhat on sample age, although errors resulting from sample handling obscure the trends.