The use of a rotor‐stator mixer as a homogenisation device to make miniemulsion droplets with industrially pertinent solid contents was investigated. Methyl methacrylate/butyl acrylate (50:50 w/w ratio) miniemulsions with droplet diameters from 2 µm to 300 nm and polydispersity indices from 1.2 to 3.6 were used. Miniemulsions with three different mean droplet diameters (300, 400, 600 nm) were polymerised and the evolution of particle size was observed. When 300 nm droplets were polymerised they yielded particles of similar diameter to the original droplets, whereas particle coalescence of the growing particles with a loss of control over the particle size distribution was observed for the 400 and 600 nm droplets. The influence of costabiliser, agitation speed, solid content, colloidal protectors and surface coverage on the evolution of the droplet size and size distribution as well as on the evolution of the average particle size and its distribution were examined. It was observed that changing the above parameters had no impact on the evolution of the particle size, suggesting we have a very robust miniemulsion system.

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A general model has been developed to describe the cross‐link density development during the free radical copolymerization of vinyl/divinyl monomers. The conventional copolymerization theory based on the terminal model is applied to the cross‐linking system in a novel way. The cross‐link density profile is illustrated for both batch and standard semi‐batch processes. A new semi‐batch feed procedure is proposed that results in a uniform cross‐link density throughout the reaction.