Metallinitierte Ringöffnungspolymerisation von funktionalisierten Lactonen und cyclischen Carbonaten

In this work various metal complexes were presented as initiators for the ring-opening polymerisation (ROP) of lactones and cyclic carbonates. First the synthesis of poly(trimethylene carbonat) PTMC was performed using triscyclopentadienyl compounds of rare earth metals. Polymerisation proceeds without elimination of carbon dioxide which can be proofed by NMR-analysis. Furthermore could be shown that tris(bis(phosphanyl)amidcomplexes of yttrium, lanthanium, neodym and erbium initiate the ROP of caprolactone CL and trimethylene carbonate TMC, whereby the resulting high molecular weight polymers could be isolated in good yields. A comparative study of [Sm{N(SiMe3)2}3] and [Sm(NPtBu3)(NHPtBu3){N(SiMe3)2}3] indicates clearly high reactivity in ROP of CL for both initiators. The system SmI2/Sm was introduced in the ROP of TMC and its dimethylsubstituted derivative DTMC. The molecular weights of the homopolymers are lower in case of bulk polymerisation compared to polymerisation in solution. An influence of the temperature could not be observed. The observed molecular weights increase with increasing monomer-to-initiator ratio without reaching the calculated level. TMC was copolymerised with dilactide LA and DTMC using SmI2/Sm as initiator. The resulting statistical copolymers were characterised by thermal analysis. SmI2/Sm is also an suitable initiator for copolymerisation of ethylene carbonate with TMC or DTMC. The moiety of EC in the polymers shows no dependency from the monomer ratio in the starting mixture. From NMR-analysis could be concluded that blocks consisting of TMC are linked by single units of EC. Statistical copolymers of 4-Brom-caprolactone und CL were synthesized using neodym(III)isopropoxide as initiator. The resulting polyesters could be used as macro initiators for the living radical polymerisation of methylmethacrylate MMA, whereby graftcopolymers consisting of a poly(caprolactone) backbone and poly(methylmethacrylate) side chains were formed. Polyesters with unsaturated side chains were produced by statistical copolymerisation of 2-allyl-valerolactone AVL and valerolactone VL. It was also possible to synthesize unsaturated polyestercarbonates by copolymerisation of AVL and TMC. Crosslinking could be demonstrated using torsion rheological techniques. Enyzamtic degradation as well as hydrolysis of formed polycarbonates and polyesters were also studied.