Preparation of hydrophobic polymer particles by radical polymerization and subsequent modification into magnetically doped particles



The application potential of hydrophobic polymer is numerous. Lauryl methacrylate (LMA) having long alkyl chain is a commercially available hydrophobic monomer. In this investigation, poly-LMA (PLMA) latex particles were prepared by suspension polymerization in aqueous media using 2,2′-azobis(isobutyronitrile) (AIBN) in presence of poly(vinyl alcohol) (PVA) as steric stabilizer. The preparation kinetics was studied in detail in terms of percentage yield and particle size variation. Low glass transition temperature (∼ −65°C) associated with high flexibility did not allow electron micrographic observation though 1H-NMR and particle size measurement confirmed the formation of PLMA latex. To improve the glass transition temperature, aqueous emulsion copolymerization of LMA with methyl methacrylate (MMA) was carried out. The solubility of LMA was improved by adding ethanol to the aqueous phase. Two types of polymeric stabilizers, PVA and poly(vinyl pyrrolidone) (PVP) were used to stabilize the colloidal particles. The nature of the stabilizer affected both morphology and final rate of polymerization. The hydrophobic P(LMA-MMA) copolymer particles were subsequently modified by nanosized magnetic (Fe3O4) particles by two different methods. The in situ formation of Fe3O4 particles in presence of P(LMA-MMA) was found to be suitable for the preparation of magnetic latex particles. Scanning electron microscope (SEM), FTIR, transmission electron microscope (TEM), X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDX) were used for the characterization of magnetically doped particles. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013