Mechanistic analysis and thermochemical kinetic simulation of the products from pyrolysis of poly(α-methylstyrene), especially the unrecognized role of phenyl shift

Poutsma, Marvin L.

doi:10.1016/j.jaap.2007.05.005

Cited by 12 publications

(4 citation statements)

References 58 publications

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“…Actually, previous study has also revealed that only a small amount of monomers may be produced at the tail end during PAMS degradation. 38 Based on the above, we mainly focus on the head-end depolymerization reactions in this work. The depolymerization reaction described later all refer to head-end depolymerization reactions.…”

Section: Resultsmentioning

confidence: 99%

Side-chain engineering for high degradation performance of mandrel materials in ICF target fabrication

Zhu

Chen

Wang

et al. 2022

Phys. Chem. Chem. Phys.

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Section: Resultsmentioning

confidence: 99%

Side-chain engineering for high degradation performance of mandrel materials in ICF target fabrication

Zhu

Chen

Wang

et al. 2022

Phys. Chem. Chem. Phys.

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“…For this technology, one key problem is how to achieve effective degradation of PAMS. Despite the continuous improvement of the synthesis methods and experimental conditions, the degradation of PAMS, just like the degradation of synthetic plastics, cannot completely occur in accordance with the ideal depolymerization reaction to produce monomer, which brings about the uncertainty of degradation ( Brown and Wall, 1958 ; Poutsma, 2007 ). Obviously, this issue is not only significant for ICF research but also fundamental to the understanding of mechanisms of environmental pollution caused by common plastics that are also composed of hydrogen and carbon, etc.…”

Section: Introductionmentioning

confidence: 99%

“…Notably, researchers have realized that hydrogen atom transfer (HAT) is a universal reaction during degradation, which will lead to changes in the polymer structure. It has been well accepted that H atom on the main chain of polymers composed of light elements can be seized by free radical to form a new intrachain radical which will cause random chain scission ( Poutsma, 2007 ; Guyot, 1986 ). In this view, the occurrence of HAT reaction in PAMS may be an important reason that leads to the degradation of PAMS deviating from the ideal depolymerization process.…”

Section: Introductionmentioning

confidence: 99%

Quantum tunneling of hydrogen atom transfer affects mandrel degradation in inertial confinement fusion target fabrication

Zhu

Yang

et al. 2022

iScience

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Summary Poly-α-methylstyrene (PAMS) is considered as the preferred mandrel material, whose degradation is crucial for the fabrication of high-quality inertial confinement fusion (ICF) targets. Herein, we reveal that hydrogen atom transfer (HAT) during PAMS degradation, which is usually attributed to the thermal effect, unexpectedly exhibits a strong high-temperature tunneling effect. Specifically, although the energy barrier of the HAT reaction is only 10 −2 magnitude different from depolymerization, the tunneling probability of the former can be 14–32 orders of magnitude greater than that of the latter. Furthermore, chain scission following HAT will lead to a variety of products other than monomers. Our work highlights that quantum tunneling may be an important source of uncertainty in PAMS degradation, which will provide a direction for the further development of key technology of target fabricating in ICF research and even the solution of plastic pollution.

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“…Promising in tracking molecular distributions are kinetic Monte Carlo (kMC) methods, − as mainly demonstrated for polymerization processes . To a limited extent, the potential of kMC has also been shown for modeling polymer decomposition or thermal degradation, with examples predicting the time evolution of the molar mass distribution (MMD) (or chain length distribution (CLD)) of linear, − cross-linked, ,− star-shaped, and branched , polymers available. Most of these kMC models are based on Gillespie’s stochastic simulation algorithm (SSA). − SSA was initially developed to describe reactions between elemental species.…”

Section: Introductionmentioning

confidence: 99%

Distribution Changes during Thermal Degradation of Poly(styrene peroxide) by Pairing Tree-Based Kinetic Monte Carlo and Artificial Intelligence Tools

Dogu

Plehiers

Vijver

et al. 2021

Ind. Eng. Chem. Res.

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A tree-based kinetic Monte Carlo (kMC) model is presented that differentiates between 38 end-group pairs for isothermal degradation of poly(styrene peroxide) (PSP). The binary trees allow for fast and accurate calculation of reaction probabilities, with mass-weighted binary trees for the accurate sampling of peroxide bond fissions and hydrogen abstractions along chains. The kinetic parameters are tuned via artificial neural networks (ANNs) to successfully predict literature experimental data, among other lumped product yields. ANNs are also utilized for sensitivity analysis to unravel the effects of individual reactions on the time evolution of experimental responses and other simulation outputs, including the variations of the chain length distributions of the macrospecies. PSP degradation is characterized by three stages of degradation considering both instantaneous and time-averaged concentrations. The first stage features rapid unzipping and results in the fast production of major products benzaldehyde and formaldehyde, the second stage features the most significant level of hydrogen abstractions involving PSP and other macrospecies types, and the third stage exhibits the consumption of the remaining peroxide bonds toward oligomeric species in a wide time frame until the degradation process is finalized by the depletion of peroxide bonds. This proof-of-concept study based on unprecedentedly detailed analyses of the chemistry via kinetic Monte Carlo paves the way to further improve our understanding of chemical recycling of solid plastic waste.

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Mechanistic analysis and thermochemical kinetic simulation of the products from pyrolysis of poly(α-methylstyrene), especially the unrecognized role of phenyl shift

Cited by 12 publications

References 58 publications

Side-chain engineering for high degradation performance of mandrel materials in ICF target fabrication

Side-chain engineering for high degradation performance of mandrel materials in ICF target fabrication

Quantum tunneling of hydrogen atom transfer affects mandrel degradation in inertial confinement fusion target fabrication

Distribution Changes during Thermal Degradation of Poly(styrene peroxide) by Pairing Tree-Based Kinetic Monte Carlo and Artificial Intelligence Tools

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