Playing with process conditions to increase the industrial sustainability of poly(lactic acid)-based materials

Smit, Kyann De; Marien, Yoshi W.; Steenberge, Paul Van; D’hooge, Dagmar; Edeleva, Mariya

doi:10.1039/d2re00577h

Cited by 9 publications

(3 citation statements)

References 94 publications

(184 reference statements)

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“…It is also true that polymers of well-defined subunits, e.g., caprolactam or lactic acid esters and semi-biopolymers, can also provide information on the potential degradation of biomolecules. De Smitt attempted to generalize their degradation studies on polylactic acid semi-biopolymers to polymers containing protonated or esterified carboxylic acid moieties [53]. They assumed that typical reactions may involve both (trans)acylation and degradation transformations in radical reactions.…”

Section: Historical Backgroundmentioning

confidence: 99%

Mechanochemical Degradation of Biopolymers

Jicsinszky,

Bucciol,

Chaji

et al. 2023

Molecules

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Mechanochemical treatment of various organic molecules is an emerging technology of green processes in biofuel, fine chemicals, or food production. Many biopolymers are involved in isolating, derivating, or modifying molecules of natural origin. Mechanochemistry provides a powerful tool to achieve these goals, but the unintentional modification of biopolymers by mechanochemical manipulation is not always obvious or even detectable. Although modeling molecular changes caused by mechanical stresses in cavitation and grinding processes is feasible in small model compounds, simulation of extrusion processes primarily relies on phenomenological approaches that allow only tool- and material-specific conclusions. The development of analytical and computational techniques allows for the inline and real-time control of parameters in various mechanochemical processes. Using artificial intelligence to analyze process parameters and product characteristics can significantly improve production optimization. We aim to review the processes and consequences of possible chemical, physicochemical, and structural changes.

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Section: Historical Backgroundmentioning

confidence: 99%

Mechanochemical Degradation of Biopolymers

Jicsinszky,

Bucciol,

Chaji

et al. 2023

Molecules

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“…Alternatively, computer simulations can be conducted, which have been already recognized as an effective tool to probe the reaction kinetics of traditional (nonexchangeable; static) cross-linked systems. − Specifically, stochastic kinetic Monte Carlo ( k MC) simulations are capable of simulating the cross-linking process with abundant structural information storage. − Such simulations can quantitatively predict the changes of microscopic properties with the extent of reaction under different reaction conditions but can also record the compositional evolution of individual species in an sufficiently large polymer ensemble during cross-linking. , For example, utilizing coupled matrix based Monte Carlo (CMMC), De Smit et al highlighted that reaction conditions for (epoxy-amine-acetoacetate)-based vitrimers need to be optimized to enable a maximization of the number of dynamic groups in a given molecule.…”

Section: Introductionmentioning

confidence: 99%

The Dynamic Interplay of Cross-Linking and Exchange Reaction Probabilities during Vitrimer Synthesis: A Monte Carlo Approach

Liu,

Jin,

Conka

et al. 2024

Macromolecules

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Covalent adaptable networks (CANs) are based on an associative exchange mechanism, and hence, vitrimers have been shown to be an attractive candidate for the synthesis of sustainable cross-linked materials due to synergetic structural stability and reprocessability. Herein, matrix-based kinetic Monte Carlo (kMC) simulations are performed to increase our mechanistic understanding of vitrimer synthesis, selecting step-growth vinylogous carbamothioate (VC)-based CANs as dynamic chemistry. Novelties are (i) the consideration of 8 elementary reaction categories differentiating between cross-linking and exchange reactions as well as inter- and intramolecular reactions (22 in total); and (ii) a dedicated tuning strategy of both intrinsic and diffusion parameters, employing experimental data from Fourier transform infrared spectroscopy and rheological measurements. Upon a model validation at different temperatures (30–60 °C), revealing a key role for mobility constraints due to viscosity increases, emphasis is on the evolution of molecular properties such as the branching density, the reduced mass-average degree of polymerization, the mass-average molar mass, and the mass fraction of the sol, to understand the relationship of kinetics, reaction probabilities, and molecular network properties. The simulation results demonstrate that increasing the temperature to, e.g., 60 °C, sufficiently promotes the exchange rate, leading to a gel point realization at higher conversion enabling the production of more uniform cross-linked structures. They also show that at higher yield, more intramolecular reactions come in to play, complicating the network structural arrangement. It is further shown that the traditional Flory and Macosko–Miller theories are no longer applicable to predicting gel points and molecular properties in dynamic network systems with higher exchange rates. Moreover, the generation of branched and cross-linked structures can be delayed with the increase of the molar ratio of primary amine groups to acetoacetate groups. The current study provides an in-depth understanding of the reaction kinetics for the synthesis of VC-based CANs, and it is an important step toward a generalized elementary reaction step driven kinetic model as well as chemistry design for vitrimer synthesis.

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“…In case sufficient macromolecular or polymeric detail is required, so-called coupled matrix-based kinetic Monte Carlo (CMMC) simulations are promising [11][12][13][14]. In such simulations, the chemical and physical interactions are executed discretely for an ensemble of molecules according to fundamental probabilities and kinetic rate laws, and structural information regarding functional groups and monomer unit rate dependencies is stored in coupled matrices.…”

Section: Introductionmentioning

confidence: 99%

Kinetic Monte Carlo Convergence Demands for Thermochemical Recycling Kinetics of Vinyl Polymers with Dominant Depropagation

et al. 2023

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As societal interest in recycling of plastics increases, modeling thermochemical recycling of vinyl polymers, e.g., via pyrolysis or reactive extrusion, becomes increasingly important. A key aspect remains the reliability of the simulation results with fewer evaluation studies regarding convergence as in the polymerization or polymer reaction engineering field. Using the coupled matrix-based Monte Carlo (CMMC) framework, tracking the unzipping of individual chains according to a general intrinsic reaction scheme consisting of fission, β-scission, and termination, it is however illustrated that similar convergence demands as in polymerization benchmark studies can be employed, i.e., threshold values for the average relative error predictions on conversion and chain length averages can be maintained. For this illustration, three theoretical feedstocks are considered as generated from CMMC polymer synthesis simulations, allowing to study the effect of the initial chain length range and the number of defects on the convergence demands. It is shown that feedstocks with a broader chain length distribution and a long tail require a larger Monte Carlo simulation volume, and that the head–head effects play a key role in the type of degradation mechanism and overall degradation rate. A minimal number of chains around 5 × 105 is needed to properly reflect the degradation kinetics. A certain degree of noise can be allowed at the higher carbon-based conversions due to the inevitable decrease in number of chains.

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Playing with process conditions to increase the industrial sustainability of poly(lactic acid)-based materials

Abstract: Polylactic acid (PLA) is an important polymer for the replacement of oil-based polymers in the biomedical field as well as for degradable single use polymeric materials. To fully exploit the...

Cited by 9 publications

References 94 publications

Mechanochemical Degradation of Biopolymers

Mechanochemical Degradation of Biopolymers

The Dynamic Interplay of Cross-Linking and Exchange Reaction Probabilities during Vitrimer Synthesis: A Monte Carlo Approach

Kinetic Monte Carlo Convergence Demands for Thermochemical Recycling Kinetics of Vinyl Polymers with Dominant Depropagation

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