Telechelic polynorbornenes with hydrogen bonding moieties by direct end capping of living chains
2010
Kurzhals, Steffen | Binder, Wolfgang H.
We present two novel symmetric olefins bearing hydrogen bonding moieties for the direct capping of living ring opening metathesis polymerization‐chains using Grubbs catalyst 1st‐ and 3rd‐generation. The symmetric olefins are generated via homo metathesis of the corresponding α‐olefins under aid of microwave irradiation and are used to prepare polynorbornene‐chains (Mn = 4,000-10,000 g/mol, Mw/Mn = 1.1-1.4) bearing barbiturate and thymine‐moieties. A qualitative and quantitative analysis of the generated polymers is done via MALDI‐TOF MS proving the introduction of hydrogen‐bonding moieties into the polymer chain and revealing the strong dependence of the desorption on the chemical structure of the different polymer species and high efficiencies for the end group introduction (90-99%). The efficiency of this process depends strongly on the reaction time and the equivalents of terminating agent with respect to the living end. The best results for the end group introduction are achieved by reacting the living chains with an excess of the terminating agent (5-20 equiv) for 100 h.
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