Preparation of Poly(Methyl Methacrylate/Butyl Acrylate) Nanoparticles by Miniemulsion Polymerization in the Presence of Commercially Available Hydrophobized TiO2 Nanoparticles

摘要

Poly(methyl methacrylate/butyl acrylate) particles were prepared by miniemulsion polymerization in the presence of commercially available hydrophobized TiO2 nanoparticles. The hybrid samples were prepared by miniemulsion polymerization, with a disperse phase containing the monomer(s) (MAA and BA), TiO2 nanoparticles supplied by the Cristal company (either “PC500” or “PC105”), hexadecane, and the initiator azobisisobutyronitrile (AIBN), and a continuous phase containing a surfactant dissolved in water (0.40 wt%). Different surfactants were investigated. After pre-emulsification and ultrasonication of the mixtures of the two phases, the polymerization took place under stirring for 17 h at 72 oC. The size determined for all samples with dynamic light scattering was of in the range of 90 to 140 nm. The formulation of 50 wt% MMA and 50 wt% BA yields materials with a Tg of about 20 oC, as determined by differential scanning calorimetry (DSC). The experiments showed that TiO2/polymer nanoparticles can be prepared by miniemulsion polymerization. However, the distribution of the inorganic nanoparticles is less convincing than initially expected. A change of the surfactant from SDS to CTAB yielded comparable results in terms of stability and coagulum formation, but the distribution of the inorganic particles in the polymer was not more homogeneous. Encapsulation of TiO2 nanoparticles in methyl methacrylate homopolymer model systems, appears to yield the best results. The samples were analyzed by scanning and transmission electron microscopy to evaluate the incorporation and the distribution of the inorganic nanoparticles in the polymer matrix.