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Keywords:

  • alkanes;
  • hydrophilic co-monomer;
  • kinetics (polym.);
  • miniemulsion stability;
  • radical polymerization

Abstract

Summary: In this work, the incorporation of alkane hydrocarbons in poly(styrene-co-methacrylic acid) particles via miniemulsion polymerization was investigated. The reactions were performed at 80 °C for 4 hours, using benzoyl peroxide as oil-soluble initiator. The effects of different concentrations of a hydrophilic co-monomer (methacrylic acid) and different types and concentrations of alkanes, namely n-hexadecane, n-octane and n-heptane were evaluated. Miniemulsion stability at room temperature and reaction kinetics were monitored, as well as the particles size and morphology. Results show the viability of encapsulation of alkanes in miniemulsion polymerizations, especially of alkanes with intermediate chain lengths (e.g. n-hexadecane). When short chain alkanes are incorporated the miniemulsions become less stable, due to their lower hydrophobicity. Based on monomer droplet size distribution data, it was determined that the best concentration of hydrophilic co-monomer for the studied system was 1.0 wt%.