Authors: A. Uveges, J.F. Hartmann and J. Borbely
Affilation: University of Debrecen, Hungary
Pages: 172 - 175
Keywords: copolymers, crosslinked, nanoparticles, paint and coatings
Cross-linked polymers formed by free radical polymerization in homogeneous solution or in emulsion are used in many current and emerging applications, including dental materials, protective and decorative coatings, contact lenses, super absorbent materials and hydrogels for biomaterials. In solution at low conversion the main process is the addition of monovinyl (M1) and divinyl (M2) monomers to linear radicals. At higher conversion the addition of M1 and M2 macroradicals to pendant double bonds may become significant, that leads to the formation of side chains. Also at higher conversion the addition of macroradicals to pendant double bonds may occur. When the polymer concentration becomes considerably higher, the formation of networks through cross-linkages is possible. It occurs in the gel state. The focus of this work will be pointed how to be able to prepare reactive polymeric nanoparticles with free radical polymerization in homogeneous solution without macrogelation. Although radical polymerization of multivinyl monomer usually proceeds with gelation that to yields insoluble crosslinked polymer except when the rate of crosslinker and/or reaction time (or to be more precise the conversion) was low, the use of much lower total amount of monomers causes the resulting polymer to be soluble even if at much higher rate of divinyl and the possible polymer yield is nearly 100%. The presence of large amount of good solvent enhances formation of soluble, partially crosslinked, containing pendant vinyl groups, nanosized polymer.