Functional PLA based (co)polymers via ROP and RAFT polymerization
In summary, this thesis presented the synthesis of end-functional PLAs by utilizing metalalkoxide formation mainly in the presence of Ca[N(SiMe3)2]2(THF)2. The effective and mild precatalyst yielded functional PLAs with high end group fidelity which enabled the combination of mechanistically distinct ROP and RAFT polymerization techniques. This was exploited for the preparation of block and comb type copolymers with (meth)acrylate based biocompatible comonomers. Preliminary biological studies of the functional PLA (co)polymers revealed promising results, which encourages further biological applications in addition to the already begun study of the PLA-cholesterol conjugates with regard to pneumonia. For example, the PLA-retinol conjugates could be further developed so that a targeted transport of active substances into hepatic stellate cells is made possible. In addition, the potent of the precatalyst urges its exploitation for the ROP of other cyclic lactones, either for homopolymerization or for the copolymerization with lactide. Future research will focus on the detailed elucidation of the proposed ROP mechanism in the presence of Ca[N(SiMe3)2]2(THF)2.