Preparation of reactive polymeric nanoparticles (RPNPs)

A series of reactive polymeric nanoparticles (RPNPs) was prepared by free radical nonlinear copolymerization of mono (M ₁) and trivinyl acrylic (M ₂) monomers in miniemulsion. The crosslinking density was determined by the mole ratio of the trivinyl component. It was found that the unswelled latex nanoparticles showed a narrower dispersity than in the organic solution of macromolecules. In latex, the size increased with the ratio of M ₂ monomer due to its higher polarity in the aqueous medium. However, the swollen nanoparticles, dissolved or dispersed in organic solvent, showed a higher dispersity as a function of composition and the crosslinking density. The residual vinyl groups adjacent to the nanoparticles were subjected to further crosslinking reactions. The reactive vinyl groups were detected by nuclear magnetic resonance spectroscopy (NMR). The size of particles in swollen state was determined by dynamic laser light scattering (DLS) method and the dried form by scanning electron microscopy (SEM). It was found that size of RPNPs is in the range of 50 to 500 nm. These particles possess properties that may allow their application in areas as disparate as dental filling material and as a component in industrial powder-based coatings.