A Critical Assessment of the Kinetics and Mechanism of Initiation of Radical Polymerization with Commercially Available Dialkyldiazene Initiators

Moad, Graeme

doi:10.1016/j.progpolymsci.2018.08.003

Cited by 82 publications

(57 citation statements)

References 491 publications

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“…For instance, polymerisation decay can also be caused by diminishing initiator efficiency at high monomer conversions, which has been observed for some azo-initiators. 30,31 However, this factor normally becomes significant at much higher conversions than the ones we reported. Attempts to perform the polymerisation at an even lower temperature (30°C) using VA-044 as the source of radicals resulted in a very long induction period followed by a short period of linear increase of the fractional concentration of monomer until a change in kinetics was again evident (Fig.…”

Section: Papercontrasting

confidence: 54%

Poly(Boc-acryloyl hydrazide): the importance of temperature and RAFT agent degradation on its preparation

Creese

Adoni

et al. 2019

Polym. Chem.

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Section: Papercontrasting

confidence: 54%

Poly(Boc-acryloyl hydrazide): the importance of temperature and RAFT agent degradation on its preparation

Creese

Adoni

et al. 2019

Polym. Chem.

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“…This treatment seems logical given that the ratio of monomer to radicals is much lower in the starved-feed semi-batch system compared to batch polymerization, leading to more primary radical termination. [51,52] The lowered monomer concentrations in the semi-batch system lead to lowered polymer molar masses compared to batch, a result well-represented by the model.…”

Section: Tmaemc Homopolymerization Modellingmentioning

confidence: 76%

Experimental and Modeling Investigation of Radical Homopolymerization of 2‐(Methacryloyloxyethyl) Trimethylammonium Chloride in Aqueous Solution

Ezenwajiaku

Chovancová

Lister

et al. 2019

Macro Reaction Engineering

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The radical homopolymerization kinetics of 2‐(methacryloyloxyethyl) trimethylammonium chloride (TMAEMC) in aqueous solution is investigated across a wide range of initial monomer contents (5–35 wt%), ionic strengths, and pH levels using an in‐situ NMR technique to track monomer consumption over the complete conversion range. Molar mass distributions (MMD) of the final homopolymers are also examined, with additional batch and semi‐batch experiments conducted in a stirred vessel. The rates of monomer conversion and polymer MMDs are dependent on initial monomer content but almost entirely independent of pH and the presence of salts, with some acceleration of rate observed for low monomer levels at very high salt concentration. To aid with the interpretation of these results, the conductivity and counterion activity of monomer and polymer mixtures are measured to determine the extent of electrostatic interactions at various levels of conversion. These results are combined with recently reported measurements of TMAEMC homopropagation kinetics to develop a TMAEMC homopolymerization model that captures the systematic decrease in rates of monomer conversion observed with increased initial monomer content during batch polymerization as well as provides a good representation of semi‐batch polymerization.

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“…The term 2 × f × I ½ 0 × 1− e kdt À Á corresponds to the total number of radicals generated from the initiator where f is the initiator efficiency (assumed to be 0.6 in the present work) and k d is the rate constant of decomposition for KPS (k d = 5.1 × 10 16 e −140.2/RT ) 48 and AIBN (k d = 4.47 × 10 15 e −131.7/RT ). 49 Based on the significantly higher polymerization rates in miniemulsion than bulk, it follows that the livingness would, based on theory, be higher in miniemulsion for a given degree of polymerization. In order to quantify this effect, the theoretical livingness was plotted versus the experimental DP ( Fig.…”

Section: Bulk and Miniemulsion Polymerizationmentioning

confidence: 99%

Exploitation of Compartmentalization in RAFT Miniemulsion Polymerization to Increase the Degree of Livingness

Khan

Guimarães

Zhou

et al. 2019

J. Polym. Sci. Part A: Polym. Chem.

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It is demonstrated that the degree of livingness (chain‐end fidelity) in RAFT polymerization for a given degree of polymerization can be markedly increased in miniemulsion polymerization relative to the corresponding homogeneous bulk system. Polymerization of styrene was conducted using a poly(methyl methacrylate) benzodithioate as macroRAFT agent in both miniemulsion and bulk. The substantially higher polymerization rate in miniemulsion, which is attributed to the segregation effect (compartmentalization) causing a reduction in the rate of bimolecular termination, makes it possible to reach a given degree of polymerization in a significantly shorter time than in the corresponding bulk system. As a consequence, fewer initiating radicals are required throughout the polymerization, leading to higher livingness in the more rapid miniemulsion system. It is demonstrated how this approach facilitates synthesis of high‐molecular‐weight block copolymers comprising slowly propagating monomers such as styrene and methacrylates. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1938–1946

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A Critical Assessment of the Kinetics and Mechanism of Initiation of Radical Polymerization with Commercially Available Dialkyldiazene Initiators

Cited by 82 publications

References 491 publications

Poly(Boc-acryloyl hydrazide): the importance of temperature and RAFT agent degradation on its preparation

Poly(Boc-acryloyl hydrazide): the importance of temperature and RAFT agent degradation on its preparation

Experimental and Modeling Investigation of Radical Homopolymerization of 2‐(Methacryloyloxyethyl) Trimethylammonium Chloride in Aqueous Solution

Exploitation of Compartmentalization in RAFT Miniemulsion Polymerization to Increase the Degree of Livingness

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