Studies of redox polymerization. I. Aqueous polymerization of acrylamide by an ascorbic acid–peroxydisulfate system

Narain, Harish; Jagadale, S. M.; Ghatge, N. D.

doi:10.1002/pol.1981.170190518

Cited by 24 publications

(11 citation statements)

References 23 publications

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“…It is well established that acrylic polymerizations undergo chain transfer to polymer and that this side reaction is more pronounced at higher temperatures (see Figure S5). − In view of this problem, a well-known low-temperature redox initiator couple − composed of KPS and AsAc was used to conduct the RAFT aqueous emulsion polymerization of nBA at 30 °C in order to minimize the degree of branching (Scheme ).…”

Section: Results and Discussionmentioning

confidence: 99%

Synthesis and Characterization of Waterborne Pyrrolidone-Functional Diblock Copolymer Nanoparticles Prepared via Surfactant-free RAFT Emulsion Polymerization

Deane

Musa

Fernyhough³

et al. 2020

Macromolecules

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Polymerization-induced self-assembly enables the facile synthesis of a wide range of block copolymer nano-objects in the form of concentrated dispersions. In this context, many surfactant-free reversible addition−fragmentation chain transfer (RAFT) aqueous emulsion polymerization formulations have been reported using various nonionic and polyelectrolytic water-soluble precursors for the steric stabilizer block. In the present study, we examine poly(2-(N-acryloyloxy)ethyl pyrrolidone) (PNAEP) as a new nonionic stabilizer block. A trithiocarbonate-based PNAEP precursor with a mean degree of polymerization of 67 was employed as the steric stabilizer for the RAFT emulsion polymerization of styrene, n-butyl acrylate (nBA), or statistical mixtures thereof. The RAFT emulsion polymerization of styrene using a VA-044 azo initiator at 80 °C and pH 7 led to essentially full conversion within 40 min, with induction times as short as 10 min, whereas gel permeation chromatography analysis confirmed efficient chain extension and relatively low dispersities (M w /M n < 1.30). Dynamic light scattering (DLS) studies indicated that systematically increasing the target degree of polymerization (DP) from 100 to 700 enabled the z-average diameter of the resulting kinetically trapped spherical nanoparticles to be varied from 55 to 156 nm. The same PNAEP 67 precursor was then employed for the RAFT emulsion polymerization of nBA at 30 °C using a low-temperature redox initiator at pH 3. More than 99% conversion was achieved within 25 min, and efficient chain extension was observed up to a target DP of 700. However, relatively broad molecular weight distributions (M w /M n = 1.38−1.64) were obtained, presumably owing to side reactions such as chain transfer to polymer. DLS studies indicated that a series of kinetically-trapped PNAEP 67 −PnBA x spheres (where x = 100−700) exhibited z-average diameters ranging from 45 to 141 nm. Attempts to use this low-temperature initiator protocol for the homopolymerization of styrene led to essentially no conversion after 48 h at 30 °C. However, the statistical copolymerization of 45% styrene with 55% nBA could be achieved using this low-temperature redox initiator at 30 °C using the same PNAEP 67 precursor. In this case, 1 H nuclear magnetic resonance studies indicated a significantly longer induction period (95 min) compared to either homopolymerization. Nevertheless, once the statistical copolymerization commenced, essentially full conversion of both comonomers could be achieved within 45 min. Differential scanning calorimetry analysis indicated that these statistical copolymers exhibited intermediate glass transition temperatures compared to the two respective homopolymers. The film formation behavior of selected diblock copolymer nanoparticles was briefly explored.

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Section: Results and Discussionmentioning

confidence: 99%

Synthesis and Characterization of Waterborne Pyrrolidone-Functional Diblock Copolymer Nanoparticles Prepared via Surfactant-free RAFT Emulsion Polymerization

Deane

Musa

Fernyhough³

et al. 2020

Macromolecules

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“…The initial rate of polymerization increased with AA concentration up to 6 × 10 −3 mol/L, but subsequent increase in AA concentration decreases the rate and conversion. A similar study of polymerization of acrylamide was conducted with an ascorbic acid–peroxydisulfate system 9. The rate was found to be constant in the range of AA concentration between 8 × 10 −4 and 22 × 10 −4 mol/L and varied as inverse half power at higher concentrations.…”

Section: Introductionmentioning

confidence: 88%

Thermal degradation of poly(ethylene oxide) and polyacrylamide with ascorbic acid

Vijayalakshmi

Raichur

Madras

2006

J of Applied Polymer Sci

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ABSTRACT:The degradation of poly(ethylene oxide) and polyacrylamide in aqueous solution was studied with ascorbic acid. Gel permeation chromatograph was used to monitor molecular weight dynamics with time. A model based on continuous distribution kinetics showed that the experimental data matched well with theory. The results showed that the degradation of polymers is significantly enhanced in the presence of ascorbic acid. The degradation rate initially increased with ascorbic acid concentration but was independent of it at higher concentrations.

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“…The peroxydisulfate ion in the presence of different reducing agents has been used for aqueous polymerization of acrylamide [1][2][3][4], methacrylamide [5][6][7], acrylonitrile [8][9], and methylmethacrylate [10]. The peroxydisulfate ion itself was also used successfully as an initiator for the polymerization of acrylamide [11].…”

Section: Introductionmentioning

confidence: 99%

Aqueous polymerization of methacrylamide initiated by potassiumpersulfate-L-cystein hydrochloride redox system

Behari

Gupta

1984

Colloid & Polymer Sci

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Abstract:The aqueous polymerization of methacrylamide initiated by potassiumpersulfate-L-cystein hydrochloride redox system has been studied at 35 + 0.01 ~ under nitrogen atmosphere. The initial rate of polymerization has been found to be directlly proportional to the monomer and activator concentration, in the range of 1.0 x 10-to 4.0 x 10 -I moi dm -3 and 1.25 x 10 -~ to 5.0 x 10 -~ tool dm -3 respectively. The order with respect to initiator has been found to be 0.5, indicating thereby that the termination takes place by bimolecular process. The overall energy of activation has been found to be 53 _+ 1 KJ/mol.

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Studies of redox polymerization. I. Aqueous polymerization of acrylamide by an ascorbic acid–peroxydisulfate system

Cited by 24 publications

References 23 publications

Synthesis and Characterization of Waterborne Pyrrolidone-Functional Diblock Copolymer Nanoparticles Prepared via Surfactant-free RAFT Emulsion Polymerization

Synthesis and Characterization of Waterborne Pyrrolidone-Functional Diblock Copolymer Nanoparticles Prepared via Surfactant-free RAFT Emulsion Polymerization

Thermal degradation of poly(ethylene oxide) and polyacrylamide with ascorbic acid

Aqueous polymerization of methacrylamide initiated by potassiumpersulfate-L-cystein hydrochloride redox system

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