Performance analysis of kinetic Monte Carlo algorithms for synthesis of linear polymers

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Pushing forward the predictive power of kinetic Monte Carlo simulations for detailed (de)polymerization chemistries

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Unravelling the wavelength dependency of anthracene photoinitiated reactions

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Surfactant-Free Peroxidase-Mediated Enzymatic Polymerization of a Biorenewable Butyrolactone Monomer via a Green Approach:Synthesis of Sustainable Biobased Latexes

A green surfactant-free one-pot horseradish peroxidase-mediated enzymatic polymerization is successfully applied to produce a sustainable and thermally stable biobased high average molar mass poly(α-methylene-γ-butyrolactone) (PMBL) at ambient conditions in water for the first time. The initiation step required only very low concentrations of hydrogen peroxide and 2,4-pentanedione water-soluble initiator to generate the keto-enoxy radicals responsible for forming the primary latex particles. The polymer nanoparticles can be seen as monodisperse, and the biobased latexes are colloidally stable and likely stabilized by the adsorption of 2,4-pentanedione moieties on the particle surfaces. Polymerizations in air produced a 98% yield of PMBL after only 3 h, highlighting the relevance of molecular oxygen. An array of characterization techniques such as dynamic light scattering (DLS), Fourier transform infrared (FTIR), 1H, 13C, and HSQC two-dimensional (2D) nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and size-exclusion chromatography (SEC) are used to confirm the properties of the synthesized latexes. The PMBL exhibited high thermal stability, with only a 5% weight loss at 340 °C and a glass-transition temperature of 200 °C, which is double that of polymethyl methacrylate (PMMA). This research provides an interesting pathway for the synthesis of sustainable biobased latexes via enzymes in a green environment using just water at ambient conditions and the potential use of the polymer in high-temperature applications.</p

Surfactant-Free Peroxidase-Mediated Enzymatic Polymerization of a Biorenewable Butyrolactone Monomer via a Green Approach:Synthesis of Sustainable Biobased Latexes

A green surfactant-free one-pot horseradish peroxidase-mediated enzymatic polymerization is successfully applied to produce a sustainable and thermally stable biobased high average molar mass poly(α-methylene-γ-butyrolactone) (PMBL) at ambient conditions in water for the first time. The initiation step required only very low concentrations of hydrogen peroxide and 2,4-pentanedione water-soluble initiator to generate the keto-enoxy radicals responsible for forming the primary latex particles. The polymer nanoparticles can be seen as monodisperse, and the biobased latexes are colloidally stable and likely stabilized by the adsorption of 2,4-pentanedione moieties on the particle surfaces. Polymerizations in air produced a 98% yield of PMBL after only 3 h, highlighting the relevance of molecular oxygen. An array of characterization techniques such as dynamic light scattering (DLS), Fourier transform infrared (FTIR), 1H, 13C, and HSQC two-dimensional (2D) nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and size-exclusion chromatography (SEC) are used to confirm the properties of the synthesized latexes. The PMBL exhibited high thermal stability, with only a 5% weight loss at 340 °C and a glass-transition temperature of 200 °C, which is double that of polymethyl methacrylate (PMMA). This research provides an interesting pathway for the synthesis of sustainable biobased latexes via enzymes in a green environment using just water at ambient conditions and the potential use of the polymer in high-temperature applications.</p

A Generic Combined Matrix- and Lattice-Based Kinetic Monte Carlo Modeling Tool to Tune Surface-Initiated Polymerization

The development of biofunctionalized polymer interfaces through the deposition of bio-derived polymeric layers to flat surfaces has attracted much attention, due to the wide range of potentially relevant applications. [...

Coupled stochastic simulation of the chain length and particle size distribution in miniemulsion radical copolymerization of styrene and N-vinylcaprolactam†

Kinetic Monte Carlo modeling is applied for the coupled simulation of the chain length and particle size distribution (CLD and PSD) in isothermal batch miniemulsion copolymerization of styrene and N-vinylcaprolactam (VCL), which are an interesting comonomer pair in view of thermoresponsive polymer nanoparticle applications. Considering a polymerization temperature of 333 K and the oil soluble initiator azobisisobutyronitrile (AIBN), it is shown that disparate terminal monomer reactivity ratios induce consecutive dominant incorporation of styrene and VCL, ultimately leading to a bimodal CLD with relevance of diffusional limitations on termination. Moreover, the initial comonomer fractions are shown to affect the ability of growing oligomers to exit the particle in which they have been generated, thereby affecting the CLD evolution. A strong effect of the initial (Gaussian) PSD is also highlighted, with much higher polymerization rates if this PSD shifts to lower particle sizes. Overall, a very dynamic PSD evolution is simulated, with negative skewing at low monomer conversions and uniformization of the PSD as the monomer conversion increases. The current modeling platform can be further extended with additional reactions such as crosslinking on a longer term

New Insights in the Treatment of Waste Water with Graphene: Dual-Site Adsorption by Sodium Dodecylbenzenesulfonate

For the adsorption of sodium dodecylbenzenesulfonate (SDBS) in aqueous solution on reduced graphene oxide (rGO), it is demonstrated that the dual-site mechanism is strongly favored over the conventional single-site one. The dual-site adsorption isotherm is derived, and regression analysis is successfully applied to experimental UV–vis data (1 g L^–1 rGO; 298–318 K; 100–900 mg L^–1 SDBS; pH: 4–11), considering reparametrization to minimize the correlation between the parameter estimates (dual site: Δ<i>H</i>° = −37.1 ± 1.3 kJ mol^–1; Δ<i>S</i>° = 35.5 ± 4.1 J mol^–1 K^–1; <i>q</i>_<i>∞</i> = 546.9 ± 8.6 mg_SDBS g_rGO^–1). A temperature of 298 K is identified as the optimal operating temperature with contact times of ca. 30 h (700 mg L^–1 SDBS). An improved regression analysis strategy, carefully selecting only low contact times (maximal 10 h), allowed assessment of the dual-site adsorption and desorption coefficient as (1.2 ± 0.3) × 10^–4 L mg_SDBS^–1 h^–1 and (2.8 ± 0.7) × 10^–3 h^–1. Moreover, by the additional presence of sodium chloride (1.2 × 10⁴ mg L^–1), a much lower contact time of ca. 10 h can be selected to ensure an as good as complete SDBS removal, highlighting the potential of the SDBS/rGO system for wastewater treatment