Does bimolecular termination dominate in benzoyl peroxide initiated styrene free-radical polymerization?

Jiang, Qimin; Xia, Deyong; Liu, Chang; Jiang, Qilin; Li, Jianhan; Han, Baohui; Jiang, Bibiao; Huang, Wenyan; Xue, Xiaoqiang; Yang, Hongjun; Jiang, Li; Dai, Qing

doi:10.1016/j.polymer.2020.122184

Cited by 11 publications

(7 citation statements)

References 56 publications

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“…The initiator concentration indices of all three monomers were close to the theoretical value of the first‐order reaction kinetics equation of free radical polymerization, which is 0.5. It indicated that the chain termination mode in the reaction was mainly double base termination 26 …”

Section: Resultsmentioning

confidence: 99%

The comparison of polymerization activity of typical cationic quaternary ammonium salt monomers

Ming,

Li,

Sun

et al. 2024

Polymers for Advanced Techs

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The cationic water‐soluble polymers, which are widely used in many areas such as papermaking and separation process, are typically synthesized through polymerization of cationic monomers represented by quaternary ammonium salt. In this work, the polymerization reaction kinetics of three typical quaternary ammonium salt cationic monomers including acryloyl oxygen ethyl trimethyl ammonium chloride (DAC), methyl acryloyl oxygen ethyl trimethyl ammonium chloride (DMC), and methyl acrylamide propyl trimethyl ammonium chloride (MAPTAC) was examined by using the dilatometer method. The results showed that the polymerization rate of all three monomers increased with the increase of initiation temperature, monomer concentration, and initiator concentration. Under the same conditions, the polymerization activity of the three monomers followed the order: DAC > DMC > MAPTAC. The activation energies for the polymerization reaction under the specified conditions were EaDAC = 138.97 kJ/mol, EaDMC = 141.24 kJ/mol, and EaMAPTAC = 226.97 kJ/mol, respectively. The polymerization rate equations were RpDAC = k1[M]4.25[I]0.51, RpDMC = k2[M]3.77[I]0.50, and RpMAPTAC = k3[M]3.30[I]0.49. The polymerization activity of the monomers may be influenced by electronic effects and steric hindrance of the monomer structure. This work has provided a theoretical and experimental foundation for the actual work of structural design and preparation of cationic water‐soluble polymers.

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Section: Resultsmentioning

confidence: 99%

The comparison of polymerization activity of typical cationic quaternary ammonium salt monomers

Ming,

Li,

Sun

et al. 2024

Polymers for Advanced Techs

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“…In particular, the results of the simultaneous comparison showed that the activation energy of DMDAAC ( E a ) was significantly higher than that of the other three monomers, which was contrary to the results of the homopolymerization rate measurement. A plausible explanation for this was that the non‐negligible hydrophobic effect of the methyl aryl diallyl ammonium chloride monomer or the steric effect of the polymer chain restrained isolation of the radical chain ends, which led to an increase in the chain termination activation energy E at 39,40 …”

Section: Discussionmentioning

confidence: 99%

Effect of substitution groups on the homopolymerization activity of methyl aryl diallyl ammonium chloride

Jia

Wang

Yang

et al. 2023

Polymers for Advanced Techs

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Dimethyl diallyl ammonium chloride (DMDAAC), recognized for its high positive charge density among the several diallyl quaternary ammonium cationic monomers, has been constrained in lipophilic applications by its structure. In this article, benzyl, p-methylbenzyl, and p-nitrobenzyl were introduced as structural modifications of DMDAAC to compensate for this. The effects of the introduced aryl structures on the molecular structure of the modified diallyl methyl aryl ammonium chloride and the polymerization activity of the monomers were explored by quantum chemical calculations and homopolymerization kinetic studies with ammonium persulfate (APS) as initiator. The results intuitively revealed the negative effect posed by the electronabsorbing effect of the substituents on the polymerization activity of the monomers, and also highlighted the important role of the steric effect. The above work has provided a good theoretical foundation and experimental reserve for further research on the preparation and application of methyl aryl diallyl ammonium chloride.

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“…Obviously, we can get insight into the polymerization mechanism by measuring the contents of the characteristic structures A, B, C, and D. should be ascribed to the methyne (CH(Ar)CH(Ar)) of the characteristic structure D from coupling termination in Scheme 2. [28] Resonances at chemical shifts of 3. For reasonable information to understand the initiation and termination mechanism, it is necessary to provide further evidence to confirm the assignments of the resonances in Figure 2.…”

Section: Nmr Studies On the Polymerization Mechanismmentioning

confidence: 99%

“…As for termination, coupling termination dominated in the polymerization initiated by H 2 O 2 /FeSO 4 , which is in sharp contrast with benzoyl peroxide initiated styrene free-radical polymerization in bulk or in solution, where primary termination predominately occurred regardless of the feed ratios and the polymerization condition. [28] This result should come from the fact that H 2 O 2 has excellent solubility in water, so the formed HO˙ primary radical will stay in aqueous phase for some time longer instead of immediately depositing onto the surface of the micelle and entering into the micelle, and then initiation and propagation occurred in aqueous phase, so most of the radicals entered into the micelle should be short-chain radical rather than HO˙ primary radical, and coupling termination predominately occurred between the existing chain radical and the entering short-chain radical. When butyl and cumyl hydroperoxides were used as the initiator, coupling termination fraction decreased markedly compared with that in H 2 O 2 /FeSO 4 system, which should mainly come from the decreased solubility in water of these hydroperoxides besides other factors.…”

Section: Nmr Studies On the Polymerization Mechanismmentioning

confidence: 99%

“…Studying on initiation and termination mechanism of radical polymerization is of significant values in controlling polymer structures and polymer properties, because different structures coupling termination dominates in termination regardless of the feed ratios and polymerization condition. [28] Emulsion poly merization is widely used in polymer preparation because of a series of advantages, for example, free of solvent, fast poly merization rate, and capable of preparing polymers with high molecular weights. [2,24,[29][30][31] In emulsion polymerization, it is considered that the termination mode includes primary termination, coupling termination between the entering short-chain radicals and the existing chain radical, [2,24] but the effects of initiators with different substituents on initiation and termination mechanisms have not been studied in detail.…”

Section: Introductionmentioning

confidence: 99%

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Initiation and Termination in Styrene Free‐Radical Polymerization Initiated by Redox Initiation

Han

Huang

et al. 2020

Macro Chemistry & Physics

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Hydrogen peroxide and hydroperoxides with substituents of different size are combined with ferrous sulfate to form redox initiation systems, which are used to initiate the polymerization of styrene in emulsion. Gas chromatography and size‐exclusion chromatography are used to measure the monomer conversion and the molecular weight of the polystyrene. Nuclear magnetic resonance is used to identify the characteristic structures, quantitative information is used to understand the polymerization. The results suggest that the initiation of the primary radicals directly depend on the size of the substitute, hydroxyl radical shows almost no selectivity between head‐addition and tail‐addition during initiation (Fhi = 47.4%). But for primary radicals with big substitute groups, for example, t‐butyl and cumyl hydroperoxides, tail‐addition takes advantages over head‐addition during initiation (Fhi ≈80%). As for the termination mechanism, it mainly depends on the solubility of the peroxide in water, the interfacial area of the particle as well as the diffusion rate of the primary radical in aqueous phase. Primary termination dominates in the polymerization initiated by hydroperoxide with poor solubility in water, for example, Fpt = 75–80% for t‐butyl and cumyl hydroperoxides. But Fpt is only 18.3% in the polymerization initiated by hydrogen peroxide (H2O2), indicating coupling termination predominately occurred because H2O2 has excellent solubility in water.

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Does bimolecular termination dominate in benzoyl peroxide initiated styrene free-radical polymerization?

Cited by 11 publications

References 56 publications

The comparison of polymerization activity of typical cationic quaternary ammonium salt monomers

The comparison of polymerization activity of typical cationic quaternary ammonium salt monomers

Effect of substitution groups on the homopolymerization activity of methyl aryl diallyl ammonium chloride

Initiation and Termination in Styrene Free‐Radical Polymerization Initiated by Redox Initiation

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