Termination Kinetics of 1‐Vinylpyrrolidin‐2‐one Radical Polymerization in Aqueous Solution

Schrooten, Jens; Buback, Michael; Hesse, Pascal; Hutchinson, Robin A.; Lacı́k, Igor

doi:10.1002/macp.201100021

Cited by 24 publications

(28 citation statements)

References 44 publications

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“…[26,33] Pulsed-laser polymerization techniques have also been applied to the study of termination kinetics of water-soluble monomers in aqueous solution. [40] The data shown were measured at 200 MPa to improve IR signal quality, but similar trends have been observed for MAA, [41] AA, [42,43] and AAm [44] at both high and low pressures. [39] As viscosity can vary significantly with composition of monomerwater mixtures, so too does the low-conversion value of k t,ss .…”

Section: Rate Coefficientssupporting

confidence: 56%

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Measuring and modelling the peculiarities of aqueous‐phase radical polymerization

Preusser

Hutchinson

2016

Can J Chem Eng

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The application of specialized pulsed-laser techniques has led to a vastly improved understanding of the kinetics of aqueous phase solution radical polymerization of water-soluble monomers. Propagation rate coefficients vary significantly with monomer concentration, an effect unique to the aqueous environment. In addition, the formation and reaction of mid-chain radicals affects polymerization rates, and thus polymer molar masses, in acrylamide and acrylic acid systems. This perspective provides an overview of these mechanistic peculiarities, which have been captured in kinetic models developed to represent the homopolymerizations of N-vinyl pyrrolidone, N-vinyl formamide, methacrylic acid, acrylic acid, and acrylamide over a wide range of conditions. The batch studies demonstrate the importance of these effects in aqueous polymerization and the validity of the rate coefficients taken from the independent kinetic studies.

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Section: Rate Coefficientssupporting

confidence: 56%

“…Dependence of NVP termination rate coefficient on conversion at 40 8C and 200 MPa for initial monomer contents of 0.40, 50, 70, 80, and 100 wt%) monomer in aqueous solution [40]. Reprinted with permission from Macromol.…”

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confidence: 99%

Measuring and modelling the peculiarities of aqueous‐phase radical polymerization

Preusser

Hutchinson

2016

Can J Chem Eng

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“…The independent knowledge of either k p or k t for the system, the PLP-derived k t expression measured for NVP [ 17 ] was retained. (In a previous study of NVF polymerization, [ 12 ] the same expression for NVP k t was combined with PLP-SEC data for NVF k p to provide a good representation of Figure 5 .…”

Section: Resultsmentioning

confidence: 99%

Free‐Radical Polymerization of N‐Vinylimidazole and Quaternized Vinylimidazole in Aqueous Solution

Santanakrishnan

Hutchinson

2013

Macro Chemistry & Physics

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Aqueous-phase free-radical batch polymerizations of N -vinylimidazole (NVI) and quaternized N -vinylimidazole (QVI) are conducted with varying initial monomer and initiator concentrations at 70 and 85 ° C. The polymerization rate of NVI is very slow at the natural pH of 9 due to degradative radical addition to monomer. The rates are increased by lowering the pH, wherein the degradative addition to NVI monomer is partially (at pH 4) and completely (at pH 1) hindered, with the polymerization rate matching that of QVI at pH 1. The initial rates of polymerization for both NVI and QVI are independent of temperature. A kinetic model developed in Predici that includes the pHdependent side reactions can reasonably represent both QVI and NVI polymerization.Schofi eld [ 4 ] on the homogeneous free-radical polymerization of N -vinylimidazole in ethanol, N , N-dimethylformamide (DMF) and water, and precipitation polymerization in bulk. The polymerization rate in ethanol was observed to reach zero-order dependence in monomer at moderately high monomer concentrations. This unusual behavior was explained by a degradative reaction between the propagating radicals and monomer, which occurs by the addition of the propagating radical to the second position of the ring, resulting in the formation of a resonance-stabilized radical as shown in Scheme 1 . The mechanism was verifi ed by studying the polymerization of 2-methyl-1-vinylimidazole, wherein higher polymerization rates were observed due to the prevention of the degradative addition, as the 2-position of this monomer is blocked by a bulky methyl group.Bamford and Schofi eld [ 4 ] observed that polymerization in water was infl uenced by NVI-water interactions, with a maximum in rate observed when water and monomer were present in approximately equal concentrations, a condition corresponding to a maximum in the viscosity of the NVI-water mixture. A signifi cant pH infl uence was also observed, with polymerization rates measured at high pH ( > 6) almost three orders of magnitude lower than those measured at low pH ( < 3). The polymer molecular weights were found to increase proportionally to rate as pH was lowered, [ 4 ] demonstrating that the increased rate

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“…The experiments were conducted at 500 and 1000 bar with n ‐heptane acting as the pressure‐transmitting fluid. The SP–PLP–NIR setup and procedure have already been detailed . The sample was irradiated with an energy of approximately 4 mJ cm −2 per laser pulse.…”

Section: Methodsmentioning

confidence: 99%

Novel Access to Propagation Rate Coefficients of Radical Polymerization by the SP-PLP-EPR Method

Kattner

Drawe

Buback

2015

Macromol. Chem. Phys.

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A novel method for kp measurement is presented, in which time‐resolved electron paramagnetic resonance detection of radical concentration after applying a single laser pulse (SP−PLP−EPR) is carried out in conjunction with measuring monomer conversion induced by the laser pulse. The method is particularly useful for the study of fully ionized monomers, as will be outlined by experiments on trimethylaminoethyl methacrylate chloride (TMAEMA, 2‐(methacryloyloxy)‐N,N,N‐trimethylethan‐1‐aminium chloride, 20 wt% in aqueous solution) at 60 °C. In addition to kp, the method provides termination rate coefficient data. The reliability of the so‐obtained rate coefficients is demonstrated by chemically induced experiments and by measuring TMAEMA conversion after single‐pulse initiation via near‐infrared (NIR) spectroscopy.

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Termination Kinetics of 1‐Vinylpyrrolidin‐2‐one Radical Polymerization in Aqueous Solution

Cited by 24 publications

References 44 publications

Measuring and modelling the peculiarities of aqueous‐phase radical polymerization

Measuring and modelling the peculiarities of aqueous‐phase radical polymerization

Free‐Radical Polymerization of N‐Vinylimidazole and Quaternized Vinylimidazole in Aqueous Solution

Novel Access to Propagation Rate Coefficients of Radical Polymerization by the SP-PLP-EPR Method

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