RHEOLOGICAL CHANGES IN EMULSION PRODUCTS WHEN AGED 597 -2 o • 0 0 0

598 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Using equations (VIII) and (IX), the values of C and E for slow phase coalescence were calculated. O/w emulsions W/o emulsions E C (k cal/mol) (sec -• x 10 -8) 6- 7 17.7 6-7 31.9 Figs. 1 and 2 show the 700 - am relationships for w/o and o/w emulsions, respectively. In both cases the data for freshly prepared and aged emulsions fall on the same curve. The curve for the o/w emulsions deviates from the exponential form at high values of •0 due to the globules being somewhat distorted when closely packed. Taking these curves in conjunction with the quoted values for E and C it was possible to construct theoretical curves for the change in 700 with ageing time. Figs. 3 and indicate that the theoretical predictions and the actual experimental data, agree very satisfactorily (8). $. Figure $ Water-in-liquid paraffin emulsions--Comparison of experimental and theoretical change. in •1 tel on aging Studies at low shear rate have been confined to w/o emulsions in which the globules flocculated very rapidly. When Dm was calculated by equation (II), which reduces to insignificance any effect due to very small