Method for removing terminal thiocarbonyl of RAFT (reversible addition-fragmentation chain transfer) polymer at room temperature

Abstract

The invention discloses a method for removing the thermal thiocarbonyl of an RAFT (reversible addition-fragmentation chain transfer) polymer at room temperature, which comprises the following steps of: firstly preparing a polymerization reaction system from a monomer, a chain transfer agent, an initiator and a first solvent; performing RAFT polymerization reaction at 60-70 DEG C for more than 1 hour; separating and purifying to obtain an RAFT polymer; preparing a reaction system from the obtained RAFT polymer, a catalysis system, a free radical capturing agent and a second solvent; reacting at 20-70 DEG C for more than 2 hours; and separating and purifying to obtain a reaction product. The method disclosed by the invention obtains a controllable product in bimodal distribution at room temperature, and can balance and optimize the processability and usability of materials under many extreme conditions; by adopting a zero-valence metal copper wire or iron wire as the catalysis system, the method has the advantages of easiness in operation, monodispersity, low price, easiness in acquisition and the like; and moreover, the method can realize recycling to save cost, and is suitable for potential large-scale production.

Description

technical field [0001] The invention belongs to the technical field of macromolecule synthesis, relates to a method for removing a thiocarbonyl group at a RAFT polymer terminal, and in particular to a simple method for removing a thiocarbonyl group at a RAFT polymer terminal at room temperature. Background technique [0002] Free radical polymerization is an important method for producing polymers in industry, and its monomers can be selected in a wide range and the reaction conditions are relatively mild. In traditional free radical polymerization, the molecular weight, molecular weight distribution and structure of the polymerized product are difficult to control due to the phenomenon of slow initiation, fast chain growth, easy chain transfer and chain termination reaction of the system. Combining the respective advantages of free radical polymerization and living polymerization, "living" / controllable free radical polymerization came into being, and has become the most imp...

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Problems solved by technology

[0008] The above method can effectively remove the thiocarbonyl group at the end of the RAFT polymer, but Chong and Chen reported that when the thiocarbonyl group at the end of polystyrene was removed by free radical-induced reduction, hydrogen atoms were extracted due to the macromolecular free radicals of polystyrene The ability of macromolecular free radicals is weak, and the ability of macromolecular free radicals is weak, and the removal effect is not as good as that of polybutyl acrylate and polymethyl methacrylate [see: Chong, Y.K.; Moad, G.; Rizzardo, E.; Thang, S.H. Thiocarbonylthio End Group Removal from RAFT-Synthesized Polymers by Radical-Induced Reduction. Macromolecules, 2007, 40, 4446–4455; Chen, M.; Moad, G.; Rizzardo, E. Thiocarbonylthio end group removal from RAFT-synthesized polymers by a radical-induced process. J. Polym. Sci., Part A: Polym. Chem., 2009, 47, 6704–6714.]

At the same time, there is no public literature report on the use of zero-valent metals to remove polystyrene terminal thiocarbonyl groups from RAFT polymers at room temperature.

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