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A method for removing the terminal thiocarbonyl group of raft polymer at room temperature

A thiocarbonyl and polymer technology, applied in the field of polymer synthesis, can solve the problems of weak free radical removal ability of macromolecules and weak ability to extract hydrogen atoms, and achieve the effects of easy operation, improved performance and cost saving.

Active Publication Date: 2015-08-19
蚌埠格识知识产权运营有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

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.

Method used

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  • A method for removing the terminal thiocarbonyl group of raft polymer at room temperature
  • A method for removing the terminal thiocarbonyl group of raft polymer at room temperature
  • A method for removing the terminal thiocarbonyl group of raft polymer at room temperature

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] Example 1: CPDB is a chain transfer agent, AIBN is an initiator, and conventional RAFT polymerization is performed

[0047] According to the ratio [St] 0 / [CPDB] 0 / [AIBN] 0 =500 / 5 / 1, add St, CPDB, AIBN and toluene in a 25mL Schlenk tube in sequence, after 6 standard freeze-purge-thaw aeration cycles, place it at a constant temperature (60℃) The reaction is carried out in a magnetically stirred oil bath for a predetermined time. After the reaction is over, take out the Schlenk tube, open it, dissolve it with 5mL of THF, pour it into 200mL of cold methanol, leave it overnight, filter with suction, and dry to obtain polystyrene (PS).

Embodiment 2

[0048] Example 2: Removal of polystyrene terminal thiocarbonyl group when TEMPO feed is small

[0049] According to the ratio [PS] 0 / [Cu(0)powder] 0 / [PMDETA] 0 / [TEMPO] 0 =1 / 5 / 5 / 10, add Cu(0)powder, PMDETA, TEMPO and PS dissolved in solvent in a 5mL ampoule, add a stir bar, and go through 6 standard freeze-purge-thaw air cycles After that, the tube was sealed in an oxygen-free atmosphere. Place the sealed ampoule in a magnetic water bath at a constant temperature (25°C) for a predetermined time to react. After the reaction is over, take out the ampoule, open the ampoule, dissolve it with 5mL of THF, and pass the solution through neutral Al 2 O 3 Chromatographic column, remove residual metals or metal ions, pour it into 200 mL of cold methanol, leave it overnight, filter with suction, and dry to obtain the product.

[0050] Polymerization conditions: St=15.0mL; [St] 0 / [CPDB] 0 / [AIBN] 0 =500 / 5 / 1; solvent is toluene; T=60℃, anaerobic; reaction conditions: PS=0.2001g; [PS] 0 / [Cu(...

Embodiment 3

[0051] Example 3: Increase the amount of TEMPO to remove the end thiocarbonyl group of polystyrene

[0052] According to the ratio [PS] 0 / [Cu(0)powder] 0 / [PMDETA] 0 / [TEMPO] 0 =1 / 5 / 5 / 20, sequentially add Cu(0) powder, PMDETA, TEMPO and PS dissolved in a solvent into a 5mL ampoule, add a stir bar, and go through 6 standard freeze-purge-thaw aeration cycles After that, the tube was sealed in an oxygen-free atmosphere. Place the sealed ampoule in a magnetic water bath at a constant temperature (25°C) for a predetermined time to react. After the reaction is over, take out the ampoule, open the ampoule, dissolve it with 5mL of THF, and pass the solution through neutral Al 2 O 3 Chromatographic column, remove residual metals or metal ions, pour it into 200 mL of cold methanol, leave it overnight, filter with suction, and dry to obtain the product.

[0053] Polymerization conditions: St=15.0mL; [St] 0 / [CPDB] 0 / [AIBN] 0 =500 / 5 / 1; solvent is toluene; T=60℃, anaerobic; reaction conditio...

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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 polymer synthesis, and relates to a method for removing the terminal thiocarbonyl group of a RAFT polymer, in particular to a simple method for removing the terminal thiocarbonyl group of a RAFT polymer at room temperature. Background technique [0002] Free radical polymerization is an important method for industrial production of polymers, with a wide selection of monomers and relatively mild reaction conditions. In traditional free radical polymerization, the molecular weight, molecular weight distribution and structure of the polymerized product are difficult to control due to the slow initiation of the system, rapid chain growth, chain transfer and chain termination reactions. Combining the advantages of free radical polymerization and living polymerization, "living" / controllable free radical polymerization came into being, and it has become the most important method of polymer synthesis. The specific me...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08F112/08C08F120/14C08F118/08C08F8/00
Inventor 张正彪张小飞朱秀林程振平朱健张伟周年琛
Owner 蚌埠格识知识产权运营有限公司