Synthese von Polydien- und Polydien-Copolymernanopartikeln mittels Miniemulsionsverfahrens
FacultiesFakultät für Naturwissenschaften
LicenseStandard (Fassung vom 01.10.2008)
The adaptation of the miniemulsion technique to the requirements of radical polymerization of volatile or gaseous diene monomers, like isoprene or butadiene, and the copolymerization of the same was the major objective of the presented work. All polyisoprene (PI) latexes show a monomodal size distribution and a long term stability of several months; the particle size can easily be varied in a range between approximately 100 to 200 nm. The use and influence of different initiator systems on the polymer particles were part of the objective for the miniemulsion polymerization of isoprene. Considering the variation of reaction temperatures (30 to 72 °C) the resulting microstructure of PI nanoparticles is quite stable consisting of 90 mol % of 1,4-units and each 5 mol % of 1,2- and 3,4-units. In addition to homopolymerization of isoprene the miniemulsion technique facilitates the copolymerization of isoprene and styrene. Miniemulsion polymerization is a powerful technique to label or load polymeric nanoparticles with fluorescent dye or bioactive compounds. The cell uptake of fluorescent PI nanoparticles was investigated. Compared to other synthetic particles, the uptake is very fast, which is probably due to a good interaction of the terpene structure of the polymer particles and the cell membrane. In this study the miniemulsion approach was modified for the purpose of polymerizing gaseous monomer which is liquefied under pressure. The miniemulsion technique can readily be applied once butadiene is liquefied under pressure. Since the copolymerization of butadiene and styrene leads to one of the industrially most interesting high butadiene SB rubbers, the miniemulsion procedure was applied to this system. The aspired weight ratio of butadiene to styrene of 75 : 25 was achieved in the miniemulsion copolymerization. The miniemulsion systems were stabilized with anionic surfactants. All presented SBR latexes show monomodal particle size distributions.
Subject HeadingsNanopartikel [GND]