The polymerization of aniline hydrochloride by inverse microemulsion in a batch process and the semicontinuous process was studied as a function of the surfactant ionic and nonionic. Polymerizations were carried out at 60°C for 4 h with a yield polymer of circa 67 and 27% wt. for ionic and nonionic surfactants. The conductivity of synthesized polyaniline by the semicontinuous process is higher up to three orders of magnitude than that of the batch process for both surfactants. The calculating degree of oxidation by UV-Vis showed the relative intensities of the quinoid to benzenoid unit around one. The morphology was determined by Scanning Electron Microscopy (SEM) and observed that the formation of the different morphologies is due to the self-assembly behavior of surfactant. The diameter z-average particle size (Dz) was studied by Transmission Electron Microscopy (TEM), which determined that the diameter particle in a semicontinuous state is larger than the one produced in a batch; this is due to the control of monomer addition in the system. These findings suggest that the polymerization process and the type of surfactant influence the properties of polyaniline.

The synthesis of core/shell polymers with tunable mechanical properties made of poly(hexyl methacrylate) (PHeMA) and poly(methyl methacrylate) (PMMA) by a two‐stage semicontinuous heterophase polymerization, is presented here. This polymerization technique is characterized by employing low surfactant concentrations to produce large polymer‐to‐surfactant ratios. In this process, monomer is added in a continuous low rate to achieve monomer starved conditions, allowing to control particle size (usually smaller than 50 nm). To modulate the mechanical properties, the weight ratio of core/shell polymers are varied from 10/90 to 90/10 for direct and reverse compositions, respectively. Conversion was followed gravimetrically; nanoparticles were characterized with quasi‐elastic light scattering, IR spectroscopy, differential scanning calorimetry, transmission electron microscopy, and mechanical tests (tensile and hardness). Highly stable latex formed of nanoparticles, with high conversions are obtained. Tensile tests show that the mechanical properties can be tuned according to core/shell composition, mainly in the system formed by PMMA/PHeMA. These results are explained in terms of core‐and‐shell polymers location, composition and hardness. As expected, an increment in concentration of PMMA produces a more rigid material independently of its position. POLYM. ENG. SCI., 59:365–371, 2019. © 2018 Society of Plastics Engineers

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