Development of Ring-Expansion RAFT Polymerization of tert -Butyl Acrylate with a Cyclic Trithiocarbonate Derivative toward the Facile Synthesis of Cyclic Polymers

• Published in: Molecules (Basel, Switzerland) Vol. 29; no. 8; p. 1839
• Main Authors: Motoyanagi, Jin, Fujii, Hiroki, Minoda, Masahiko
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 18.04.2024
• Subjects: Behavior; Conversion; cyclic polymer; cyclic trithiocarbonate derivative; Investigations; Molecular weight; Phase transitions; Polymerization; Polymers; RAFT polymerization; Reagents; ring-expansion RAFT polymerization; Spectrum analysis; tert-butyl acrylate; RAFT polymerization; cyclic trithiocarbonate derivative; cyclic polymer; ring-expansion RAFT polymerization; tert-butyl acrylate
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules29081839

Polymers with cyclic topology have no terminal structure and, therefore, exhibit various unique physical and functional properties compared to those of linear analogs. In this paper, we report an innovative methodology for the synthesis of cyclic polymers via ring-expansion RAFT (RE-RAFT) polymerization of vinyl monomers using a cyclic trithiocarbonate derivative (CTTC) as a RAFT agent. RE-RAFT of -butyl acrylate (TBA) was performed to yield a mixture of polymers exhibiting a bimodal size exclusion chromatography (SEC) trace. Both the peak top molecular weights shifted to higher-molecular-weight regions as the monomer conversion increased. The structure of the resulting polymer mixture was examined by H NMR and MALDI-TOF-MS. Detailed studies indicated that the obtained polymer of higher molecular weight was one of the large-sized cyclic polymers generated by the fusion of smaller-sized cyclic polymers during the RE-RAFT polymerization process. This approach opens the door to the simple synthesis of well-controlled cyclic polymers with complex structures, such as alternating and multi-block repeat unit sequences.