Temporal Control in Mechanically Controlled Atom Transfer Radical Polymerization Using Low ppm of Cu Catalyst

Area of Science:

• Polymer Chemistry
• Materials Science
• Chemical Engineering

Background:

• Atom Transfer Radical Polymerization (ATRP) is a versatile method for synthesizing polymers with controlled molecular weights and architectures.
• External stimuli, such as ultrasound, offer potential for precise control over polymerization kinetics and polymer properties.
• Developing efficient and catalyst-sparing polymerization techniques is crucial for sustainable chemical synthesis.

Purpose of the Study:

• To investigate the feasibility of using ultrasound as an external stimulus to control ATRP.
• To explore the use of low concentrations of copper catalyst in ultrasound-mediated ATRP.
• To study the influence of piezoelectric nanoparticles on the mechanoATRP process.

Main Methods:

• Mechanically controlled atom transfer radical polymerization (mechanoATRP) was performed in an ultrasound bath.
• Methyl acrylate was polymerized using a CuBr2/tris(2-pyridylmethyl)amine catalyst system.
• Ultrasound agitation was switched on and off to control polymerization, and piezoelectric BaTiO3 nanoparticles were employed.

Main Results:

• MechanoATRP was successfully achieved with low parts-per-million (ppm) copper catalyst concentrations.
• Polymerization kinetics followed first-order behavior during ultrasonication.
• Experimental molecular weights closely matched theoretical values, with narrow molecular weight distributions observed.
• The effects of BaTiO3 nanoparticle type, loading, and targeted degree of polymerization were investigated.

Conclusions:

• Ultrasound serves as an effective external stimulus for temporal control of ATRP.
• Low catalyst loadings are viable for mechanoATRP, enhancing efficiency and reducing metal contamination.
• The study demonstrates a promising approach for controlled polymer synthesis using mechanical energy and minimal catalyst.