Chemorheology of poly(high internal phase emulsions)

The physical packing limit of (polydispersed) spheres can be surpassed in emulsions since the liquid droplets can be deformed into polyhedrons which fill space more efficiently than spheres, thus the volume fraction of the dispersed phase can reach as high as 0.96.1 The resulting dispersion is known as a high internal phase emulsion (HIPE), or alternately as a highly concentrated emulsion (HCE), in which only a very thin film of continuous phase separates neighboring dispersed liquid droplets. It should be noted that the higher storage modulus compared to the loss modulus for the uncured samples is typical for HIPEs and indicates the solid-like behavior due to the compressed state of droplets. The greater conversion of monomers at elevated temperatures is presumably a consequence of higher propagation constants and monomer diffusion coefficients.