Nonequilibrium Morphology Development

Aerdts et al. [21] first synthesized polybutadiene seed latex particles (90nmin diameter). This was followed by the semibatch emulsion copolymerization of 

Styrene and methyl methacrylate in the presence of the rubber seed latex particles. Finally, glycidyl methacrylate was grafted onto the composite latex particles. The emulsion polymerizations were stabilized by sodium dihexyl sulfosuccinate and initiated by potassium persulfate. The functionalized composite polymer particles, which served as an impact modifier, were blended with polyamide-6, and these particles were dispersed well in the matrix of polyamide-6. 

Ferguson et al. [27] explored how to prepare latex particles with a core/ shell (polystyrene/polyvinyl acetate) structure. A variety of initiators including potassium persulfate, ammonium persulfate, 2,2 -azobisisobutyronitrile, 

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Several other machines of this type have been developed since. They all involve intensive mechanical shearing that produces extensive chain scission. Recombination of the free radicals in situ generates sufficient concentration of copolymer, to compatibilize the system. The generated-under-high-stress, nonequilibrium morphology is then locked by quenching. Best performance has been observed for systems with co-continuous morphology. 

A second class of models directly relates flow to blend structure without the assumption of an ellipsoidal droplet shape. This description was initiated by Doi and Ohta for an equiviscous blend with equal compositions of both components [34], Coupling this method with a constraint of constant volume of the inclusions, leads again to equations for microstructural dynamics in blends with a droplet-matrix morphology [35], An alternative way to develop these microstructural theories is the use of nonequilibrium thermodynamics. This way, Grmela et al. showed that the phenomenological Maffettone-Minale model can be retrieved for a specific choice of the free energy [36], An in-depth review of the different available models for droplet dynamics can be found in the work of Minale [20]. 

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