INDEX linear amines

The rates of loss do not correlate with the rates of increase in the hydroxyl index for these systems or with the photoyellowing and uv phenomena. This indicates that the mechanism of oxidation of the amine functionality is complex. An additional feature of interest is the profile of this band loss as related to terminal amine structure. In the simple alkyl substituted systems namely diethyl, dimethyl and dibutyl there is an initial rapid loss followed by a slowing down of the rate of decrease on prolonged irradiation. However, with the oxygen containing systems namely morpholine, N-ethyl ethanolamine and N-methyl ethanolamine the rate of decrease is linear with irradiation time. Evidently, there must be two different mechanisms in operation here. The loss of these infra-red absorption bands may be due to a process of dealkylation via oxidation (see reactions later). The band situated at 2978 cm"l exhibited similar behaviour although the extent of the loss was less than that observed with the previous band and the order of rate loss was marginally different. 

Post-polymerization functionalization has also been applied to the synthesis of terpyridine-modified polymers [ 126]. In a recent approach, Schubert and colleagues employed this method to prepare poly(pentafluorostyrene) with terpyridines in the side chains [127]. First, poly(pentafluorostyrene) with a narrow polydispersity index of just 1.08 was synthesized by nitroxide-mediated polymerization. In a second step, this polymer was converted with amine-functionalized terpyridine under microwave heating, selectively substituting the para-fluorines. Addition of iron(II) sulfate to a solution of the terpyridine-functionalized polymer in a mixture of chloroform and methanol leads to gelation at a polymer concentration of 33 g In another work, Schubert and coworkers prepared metal-cross-Iinked polymer networks from linear and tri-arm PEG precursors, both functionalized with terpyridine at their OH-termini [128]. Quantitative functionalization of these precursors was achieved by conversion of the hydroxy-functionalized PEG derivatives with 4-chloro-2,2 6, 2"-terpyridine under basic conditions. However, quantitative cross-linking with iron(II) chloride was not observed in methanol solutions, neither at room temperature nor at elevated temperature, but only a small quantity of cross-linked material precipitated from the solution. This observation was attributed to a strong tendency of the tri-arm PEG to form intramolecular complexes, acting as a chain stopper rather than as a cross-linker. 

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