Mechanistic and kinetic investigation of Cu(II)‐catalyzed controlled radical polymerization enabled by ultrasound irradiation

• Published in: AIChE journal Vol. 66; no. 1
• Main Authors: Bian, Chao, Zhou, Yin‐Ning, Luo, Zheng‐Hong
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.01.2020; American Institute of Chemical Engineers
• Subjects: ATRP; catalysis; Catalysts; Contamination; Copper; Degree of polymerization; Electron transfer; Irradiation; Nanoparticles; Piezoelectricity; Polymerization; Polymers; Radiation; Reaction kinetics; Reducing agents; Sonication; ultrasonication; Ultrasound
• ISSN: 0001-1541; 1547-5905
• DOI: 10.1002/aic.16746

Controlled radical polymerization (CRP) under external field has been an attractive research area in these years. In this work, a new electron transfer mechanism, that is, sonochemically induced electron transfer (SET) was introduced to mediate polymerization for the first time. The activator CuIX/L complex was (re)generated from CuIIX2/L in dimethylsulfoxide (DMSO) by the SET process in the presence of free ligand tris(2‐dimethylaminoethyl)amine (Me6TREN). The investigation of polymerization including the mechanistic insights and effect of experimental conditions on the rate of reaction has been undertaken. Kinetics of Cu(II)‐catalyzed CRPs via SET under different conditions (i.e., Me6TREN concentration, catalyst loading, targeted degree of polymerization, and sonication power) were conducted in an unprecedentedly controlled manner, yielding polymers with predetermined molar masses and low dispersities (Đ < 1.12). Attractively, the polymerization can be performed without the piezoelectric nanoparticles and exogenous reducing agent. Contamination by nonliving chains formed from sonochemically generated radicals is avoided as well. All of these results supported that Cu(II)‐based catalyst activation enabled by ultrasonication has a promising potential in scale‐up of CRP.