Continuous Monitoring and Characterization of Copolymerization Reactions of Acrylate Monomers with Indistinguishable Ultraviolet Spectra Using Infrared Spectroscopy

Siqueira, Julia S.; Reed, Wayne F.

doi:10.1002/mren.202200034

Cited by 1 publication

(1 citation statement)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“… 24 Fundamental information about the reaction and the product can be obtained through a variety of detectors—monomer conversion and copolymer composition (cumulative and instantaneous) from ultraviolet (UV) absorption spectroscopy, cumulative and instantaneous reduced and intrinsic viscosity (RV and IV, respectively) 25 from capillary viscometry, and weight-average molecular weight ( M w ) (cumulative and instantaneous) from multi-angle static light scattering (MALS). The detection module can be customized to include other instruments, such as a Fourier transform infrared spectrometer, 26 a refractive index (RI) 27 detector, dynamic light scattering, conductivity, polarimetry, and online nuclear magnetic resonance. 28 The model-free data gathered with ACOMP is what makes it such an invaluable tool for both tracking and modeling reaction kinetics, as well as controlling specific parameters of these reactions.…”

Section: Introductionmentioning

confidence: 99%

Observation and Modeling of a Sharp Oxygen Threshold in Aqueous Free Radical and RAFT Polymerization

Siqueira

Crosley²,

Reed

2022

J. Phys. Chem. B

Self Cite

View full text Add to dashboard Cite

It is known that oxygen (O2) stops radical polymerization (RP). Here, it was found that the reaction turn-off occurs abruptly at a threshold concentration of O2, [O2]t, for both free RP and reversible addition–fragmentation chain-transfer polymerization (RAFT). In some reactions, there was a spontaneous re-start of conversion. Three cases were investigated: RP of (i) acrylamide (Am) and (ii) sodium styrene sulfonate (SS) and (iii) Am RAFT polymerization. A controlled flow of O2 into the reactor was employed. An abrupt turn-off was observed in all cases, where polymerization stops sharply at [O2]t and remains stopped when [O2] > [O2]t. In (i), Am acts as a catalytic radical-transfer agent during conversion plateau, eliminating excess [O2], and polymerization spontaneously resumes at [O2]t. In no reaction, the initiator alone was capable of eliminating O2. N2 purge was needed to re-start reactions (ii) and (iii). For (i) and (ii), while [O2] < [O2]t, O2 acts a chain termination agent, reducing the molecular weight (M w) and reduced viscosity (RV). O2 acts as an inhibitor for [O2] > [O2]t in all cases. The radical-transfer rates from Am* and SS* to O2 are >10,000× higher than the initial chain propagation step rates for Am and SS, which causes [O2]t at very low [O2].

show abstract