Anwendung abbaubarer Polymer-Azo-Initiatoren in der Synthese von Blockcopolymeren, Gradientcopolymeren und nanoskaligen Latices

The aim of this thesis was the use of degradable Polymer-Azo-Initiators in the synthesis of copolymers and in mini emulsion polymerisation. In the first part of describes the synthesis of the polymeric azo initiators by polycondensation of polycaprolactone diols and azobiscyanopentanoic acid chloride. It was shown, that under the chosen conditions the reaction proceeds completely. The obtained initiators were characterised by proton nmr spectroscopy, thermogravimetry and differential scanning calorimetry. They showed the expected composition. In the next step the initiators were used for the free radical polymerisation of methylmethacrylat (MMA). The composition of the copolymers from theses reactions was also analysed by proton nmr spectroscopy. Further characterisation techniques approved the expected structure as a triblockcopolymer in the manner of PMMA-b-PCl-b-PMMA. For these triblockcopolymers the influence of composition as well as the segmental length of each block to thermodynamic and physical properties was studied. Here only the middle segment of polycaprolacton can be degraded by hydrolysis. So the synthesis was altered according to the concept to the use of a further monomer. Copolymerisation of 2-methylene-1,3-dioxepan (MDO) with MMA in the radical polymerisation yielded in the desires gradient copolymer with the structure P(MMA-stat-MDO)-b-PCl-b- P(MMA-stat-MDO). In this material the PMMA chain is interrupted by ester linkers and a complete degradation by hydrolysis was observed. The mechanical properties in this copolymer system can be adjusted in a wide range. It depends on the content of each copolymer as well as the respective microstructure. In this work also the successful use of multitasking poylcaprolactone based hydrophobin as degradable hydrophobe and initiator for miniemulsion polymerization was shown. Using this system, no further addition of a hydrophobe is necessary to get small, uniform spheres of both polystyrene and polymethylmethacrylate with high solid contents in dispersion. The system showed significant dependence upon the amount of hydrophobin present in the recipe for miniemulsion for the formation of stable dispersions. This work opens a simple method of making functional aqueous dispersions by miniemulsion. The different functionalities by this method can be controlled by choosing the appropriate prepolymers for hydrophobin synthesis.