Living Cationic Ring-Opening Homo- and Copolymerization of Cyclohexene Oxide by “Dormant” Species Generation Using Cyclic Ethers as Lewis Basic Additives

Abstract

The living cationic ring-opening polymerization of cyclohexene oxide (CHO) was demonstrated to proceed using cyclic ethers as Lewis basic additives that potentially form "dormant" species through a reaction with the CHO-derived propagating species. The polymers obtained under suitable conditions had molecular weights close to the theoretical values and narrow molecular weight distributions. The formation of the dormant species was strongly supported by the generation of chain ends consisting of a cyclic ether additive and a quencher fragment, which was confirmed by 1 H NMR and ESI-MS analysis of the product polymers. The use of additives with appropriate basicity, such as hexamethylene oxide and tetrahydropyran, is of considerable importance for living polymerization. In addition, the living copolymerization of CHO and 1,4-epoxycyclohexene and the synthesis of alternating-like acid-degradable polymers with aliphatic aldehydes were also achieved.

Photoinduced Free Radical Promoted Cationic RAFT Polymerization toward “Living” 3D Printing

“…This result may be due to the change in the structure of the R group in the cationic RAFT agent after insertion of an epoxy monomer, which forms an R group with poor leaving ability and leads to uncontrolled polymerization. 35,36 Next, this photoinduced free radical-promoted cationic RAFT polymerization was considered for constructing a 3D printing system. The SLA method was adopted to accomplish our purpose.…”

“…Relatively lower molecular weights and broad MWDs were found in the polymerization of epoxy monomers (CHOs; entry 5, Table S5). This result may be due to the change in the structure of the R group in the cationic RAFT agent after insertion of an epoxy monomer, which forms an R group with poor leaving ability and leads to uncontrolled polymerization. , …”

Living Cationic Polymerization of ε-Caprolactone Catalyzed by a Metal-free Lewis Acid of Trityl Tetrafluoroborate

“…TrBF 4 is a safe, commercialized, and inexpensive Lewis acid and has been extensively used in organic synthesis as a protection reagent or catalyst . However, the compound itself and its derivatives are much less employed in polymer synthesis. ,− Very recently, we found a derivative of TrBF 4 could induce a photo-controlled living cationic polymerization of methoxystyrene . In the present work, TrBF 4 is for the first time used to catalyze the living ROP of lactones.…”

Controlled cationic polymerization using RAFT agents with selenonium cations as metal-free Lewis acids: from homogeneous to heterogeneous catalysis

“…Low monomer conversion can be observed in the polymerization of CHO owing to the formation of a more stable structure after the insertion of epoxy monomers in the CTA, which has poor leaving ability and leads to uncontrolled polymerization. 7,48 Next, kinetic experiments were performed to study the polymerization behavior using different concentrations of the catalyst. The semi-logarithm of the monomer concentration has a linear relationship with the polymerization time, suggesting a constant concentration of the propagating species in the polymerization (Fig.…”

“…Low monomer conversion can be observed in the polymerization of CHO owing to the formation of a more stable structure after the insertion of epoxy monomers in the CTA, which has poor leaving ability and leads to uncontrolled polymerization. 7,48…”