Experimental Evaluation of the Miniemulsion Polymerization of Vinyl Pivalate: The role of the Main Process Variables

Abstract

AbstractPoly(vinyl pivalate) (PVPi) nanoparticles obtained via miniemulsion have particular properties useful for several applications. Thus, the present study aims to synthesize and characterize PVPi nanoparticles through the miniemulsion polymerization process, studying the effects of water‐soluble and oil‐soluble initiators, polymerization temperature, and the co‐stabilizer concentration on the final properties of the polymer, nanoparticle size, and conversion. The polymeric nanoparticles are characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance (1H and 13C NMR), thermogravimetric analysis, differential scanning calorimetry, gel permeation chromatography, dynamic light scattering, and transmission electron microscopy. The miniemulsion polymerization process ensures the formation of a polymeric fluid with high colloidal and thermal stability, with maximum conversions of ≈85% and average particle diameter of 97.2 ± 21.8 nm. The polymeric properties, such as molar mass and glass transition temperature (Tg), are influenced by process variables such as synthesis temperature and the type of initiator. The use of potassium persulfate and 2,2‐azobisisobutyronitrile (AIBN) initiators favors the homogeneous nucleation mechanism, resulting in a decrease in the average particle diameter and in the growth of the chains, result in greater average molar masses and, consequently, greater Tg.