Second step RAFT

The synthesis of DAAmEP was conducted in three steps. The first step was a Michaelis-Arhuzov reaction between N-(2-bromoethyl)phthalimide and an excess of triethyl phosphite under reflux at 160 °C for 12 h. In the second step, the reaction between the resulting phthalimide and hydrazine led to the formation of (2-aminoethyl)phosphonic acid diethyl ester. The final step consisted of the reaction between the actyloyl chloride and the diethyl ester, which was achieved in the presence of poly(4-vinylpyridine), 2% crosslinked, to trap the hydrochloric acid produced during the acryloylation. The final DAAmEP monomer was obtained after purification by chromatography on silica gel. All intermediate products were characterized by H and P NMR. The H NMR spectrum of the DAAmEP monomer allowed validation of the expected chemical structure and as a consequence the synthetic pathway. RAFT homopolymerization of DAAmEP was carried out with two different trithiocarbonate chain transfer agents (see Scheme 2.6). 

In RAFT block copolymerizations, the main requirement to produce AB diblocks with a low polydispersity index PDl is that the dithioester macroinitiator has a high chain transfer constant in the polymerization reaction producing the second block. In other words, in the equilibrium step... 

One of the major applications of living polymerization is the synthesis of block copolymers via sequential addition of monomers. In this approach, monomer A is rst polymerized quantitatively by the RAFT process, followed by direct addition of a second monomer for chain extension, or alternatively, the RAFT polymer of A from the rst step is puri ed and used as a macro-CTA to... 

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