Preparation of 20-nm poly(styrene derivative) particles via polymerization with nonionic surfactant at the phase-inversion temperature

Abstract

Several types of styrene monomer derivatives were polymerized in monomer, water, polyoxyethylene alkyl phenyl ether and initiator mixtures at various temperatures to form small particles. Smaller particles were obtained at higher radical generation rates at the phase-inversion temperature (PIT). Large coagula or secondary particles were obtained at temperatures higher than the PIT. The average diameter of the polymer particles obtained via the polymerization of p-methylstyrene and styrene at the PIT was smaller than those of divinylbenzene and 4-t-butylstyrene. Poly(p-methylstyrene) particles, which had an average diameter of 21 nm and a polymer weight fraction of 5%, were prepared. Poly(styrene derivative) particles, average diameter of which is <30nm, were prepared without ionic emulsifier with nonionic emulsifier polyoxyethylene alkyl phenyl ether by polymerizing monomer, emulsifier, water and initiator mixture at around PIT. Effects of initiator concentration, temperature and monomer type on the average diameter of the generated polymer particles are investigated. Smaller particles are obtained with higher rate of radical generation at PIT. The particles of poly(p-methylstyrene) which have an average diameter of 21 nm and a polymer weight fraction of 5% were prepared.