Cobalt-Mediated Radical Polymerization (CMRP) of Vinyl Acetate Initiated by Redox Systems:  Toward the Scale-Up of CMRP

Abstract

A redox initiating system was developed in order to bypass 2,2‘-azobis(4-methoxy-2,4-dimethylvaleronitrile) (V70) as the initiator of the cobalt-mediated radical polymerization (CMRP) of vinyl acetate (VAc) in the presence of cobalt(II) acetylacetonate (Co(acac)2). It is indeed a problem to stock up with V70 because of needed storage at −20 °C during transportation. This paper reports on the controlled CMRP of VAc initiated by ascorbic acid combined with either lauroyl peroxide or benzoyl peroxide at 30 °C. Substitution of citric acid for ascorbic acid results in faster polymerization whereas the polymerization control is maintained. All these improvements facilitate the implementation of the vinyl acetate CMRP and open the door to the scale-up of the process.

Competitive adsorption of uranyl ions in the presence of Pb(II) and Cd(II) ions by poly(glycidyl methacrylate) microbeads carrying amidoxime groups and polarographic determination

“…Moreover, although residual VL or VS could not be removed as easily as VAc from the reaction mixture, poly(vinyl laurate)‐ b ‐poly(vinyl stearate) (PVL‐ b ‐PVS) diblock copolymers could be prepared. The polymerization was initiated by an LPO/citric acid (CA)/Co(acac) 2 redox system as already reported by Bryaskova et al19 The low efficiency of the initiating step already reported by Bryaskova et al was observed in our case too and discussed. The thermal properties of the block copolymers were analyzed by means of DSC.…”

Cobalt‐Mediated Radical Polymerization of Acrylonitrile: Kinetics Investigations and DFT Calculations

“…As expected, the polymerization rate is much slower at 0 8C than at 30 8C and the molar masses increased linearly with monomer conversion at both temperatures. However, the molar mass is controlled much better at the lower temperature, as shown by the lower polydispersity (M w /M n % 1.15, H NMR spectroscopy after treatment with 2,2,6,6-tetramethylpiperidine N-oxide (TEMPO) according to a previously reported procedure, [10,13] and purification by precipitation ( Figure 6). Besides the typical signals of PAN (-CH 2 -CHCN-), the spectrum revealed the presence of signals characteristic of the very few VAc units (-CH 2 -CHOAc-) coming from the CMRP initiator fragment.…”

“…[9][10][11][12][13][14][15] This method involves the temporary deactivation of the growing poly-A C H T U N G T R E N N U N G (vinyl acetate) (PVAc) chains with a cobalt complex. Following this controlled radical pathway, PVAc with predictable molar mass and low polydispersity was prepared in bulk, but also in aqueous media.…”

Radical Polymerization of Vinyl Acetate with Bis(tetramethylheptadionato)cobalt(II): Coexistence of Three Different Mechanisms

“…Keywords: cobalt · density functional calculations · polymerization · radical reactions · reaction mechanisms complexes, pioneered by JØrôme and co-workers with [Co-A C H T U N G T R E N N U N G (acac) 2 ] (1; acac = acetylacetonato), [13][14][15][16][17][18] has been particularly successful. Diblock copolymers of VAc with N-vinylpyrrolidone, [19] styrene, [20] and acrylonitrile [21,22] have also been obtained by using [CoA C H T U N G T R E N N U N G (acac) 2 ].…”