Preparation of Nylon 4 microspheres via heterogeneous polymerization of 2-pyrrolidone in a paraffin oil continuous phase

The successful preparation of Nylon 4 microspheres via heterogeneous polymerization is described. Polymerization of 2-pyrrolidone (C4) was carried out in a paraffin oil/C4 heterogeneous medium containing sodium dodecyl sulfate, potassium tert-butoxide, and benzoyl chloride. The effects of polymerization variables including the stirring speed, phase ratio, and emulsifier and catalyst concentrations on the polymerization were investigated in terms of the polymerization yield, particle size and particle size distribution. By adjusting the experimental conditions, it was possible to prepare coagulation-free Nylon 4 microspheres with a high yield (∼76%) with average diameters ranging from 9.6 to 110.9 μm.