Anomale Mischkristalle und orientierte Abscheidung

Neuhaus, A.; Darmstadt, T. H.

doi:10.1002/ange.19410545103

Cited by 40 publications

(14 citation statements)

References 16 publications

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“…

\begin{matrix} left \\ r = k_{p, TDB} \cdot \frac{([], TDB)}{λ_{0}^{D} + λ_{0}^{D N}} [T^{•}] [D_{i}] \\ r = k_{p, TDB} \cdot \frac{([], TDB)}{λ_{0}^{D} + λ_{0}^{D N}} [T^{•}] [D N_{i}] \end{matrix}

A second possibility is to base the average on the number of incorporated monomer units according to Equation as proposed in ref. (denoted by superscript 1, and later on referred to as model 1).

\overset{true¯}{n_{TDB}^{1}} = \frac{([], TDB)}{λ_{1}^{D} + λ_{1}^{D N}} \cdot i

In this case, the rate for the reaction of T • with a TDB bearing dead chain D i or DN i becomes chain length dependent according to Equation .…”

Section: Resultsmentioning

confidence: 99%

Side Reactions in Aqueous Phase Polymerization of N‐Vinyl‐Pyrrolidone as Possible Source for Fouling

Deglmann

Hellmund

Hungenberg³

et al. 2019

Macro Reaction Engineering

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A first intense investigation in the kinetics of radical polymerization of NVP was done by Senogles et. al. [7] They revealed a variation of the activation energy for the propagation step Radical PolymerizationAn improved kinetic model for the radical polymerization of N-vinyl-pyrrolidone (NVP) in aqueous medium is developed. Quantum chemical simulations reveal that the transfer to polymer is of minor importance whereas the transfer to monomer by hydrogen abstraction in 3-position of the pyrrolidone ring leads to a radical with a double bond which initiates a new chain bearing a terminal double bond (TDB). The resulting dead chains with one, two, or more TDB are the main source for a strong increase of molar mass in batch reactors at high conversion due to long chain branching and crosslinking. This can be a source for gel formation and fouling in continuous reactors. www.advancedsciencenews.com www.mre-journal.de

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“…

\begin{matrix} left \\ r = k_{p, TDB} \cdot \frac{([], TDB)}{λ_{0}^{D} + λ_{0}^{D N}} [T^{•}] [D_{i}] \\ r = k_{p, TDB} \cdot \frac{([], TDB)}{λ_{0}^{D} + λ_{0}^{D N}} [T^{•}] [D N_{i}] \end{matrix}

A second possibility is to base the average on the number of incorporated monomer units according to Equation as proposed in ref. (denoted by superscript 1, and later on referred to as model 1).

\overset{true¯}{n_{TDB}^{1}} = \frac{([], TDB)}{λ_{1}^{D} + λ_{1}^{D N}} \cdot i

In this case, the rate for the reaction of T • with a TDB bearing dead chain D i or DN i becomes chain length dependent according to Equation .…”

Section: Resultsmentioning

confidence: 99%

Side Reactions in Aqueous Phase Polymerization of N‐Vinyl‐Pyrrolidone as Possible Source for Fouling

Deglmann

Hellmund

Hungenberg³

et al. 2019

Macro Reaction Engineering

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“…Therefore Neuhaus et al. , developed a coupled deterministic and stochastic simulation approach to model the polymeric microstructure independent of the reactor type. Eckes , extended that model and validated it for homopolymerizations of ethene in autoclaves.…”

Section: Literature Reviewmentioning

confidence: 99%

Modeling of High‐Pressure Ethene Homo‐ and Copolymerization

Peikert

Pflug

Busch

2019

Chemie Ingenieur Technik

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While reaction engineering of low‐molecular weight compounds mainly focuses on equilibria and selectivities, polymer properties are tremendously influenced by molecular weight distribution as well as branching structure. In order to determine the branching structure of low‐density polyethylene (LDPE) copolymers in dependence on chosen process conditions, a Monte‐Carlo approach was developed. By modeling the topology as well as the comonomer distribution in the polymer chains a deeper insight in the process‐microstructure‐properties relationship is gained.

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“…Both salts are crystallizing in a sodium-chloride structure, where the cations and anions are octahedrally surrounded by their counter ions. The major difference of these salts are their lattice constants, 5.63 Å and 6.26 Å for NaCl and KCl, respectively [34]. To our best knowledge, the incorporation procedure of the quantum dots into the ionic matrix has not been clarified in detail yet.…”

Section: Free-stabilizer Additionmentioning

confidence: 99%

QD-Salt Mixed Crystals: the Influence of Salt-Type, Free-Stabilizer, and pH

Adam

Tietze

Gaponik

et al. 2014

Zeitschrift Für Physikalische Chemie

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Colloidal quantum dots (QDs) bear a huge potential in different application fields due to their unique properties. Unfortunately, their limited stability against environmental influences and the limited processability of the colloidal solutions restricts, among other factors, their widespread implementation. Incorporating the QDs into an inorganic matrix allows overcoming of these barriers. In this manuscript, we demonstrate the reproducible incorporation of high quality CdTe QDs capped with thioglycolic acid into NaCl and KCl salt crystals. In comparison to previous reports, here we avoided the production of powder-like, weakly emitting mixed crystals and/or a loss of large amounts of QDs due to aggregation. The optimum conditions for this process were found by the variation of the amount of additional free-stabilizer and the pH of the saturated salt solutions. Both variables exhibit high influence on the colloidal stability of the QDs, ensuring the electrostatic forces on their surface to be high enough to prevent agglomeration. Incorporation in NaCl as host matrix is accompanied with pronounced etching of the QDs, causing a blue shift of the photoluminescence (PL)-spectra upon incorporation while KCl preserves the original optical properties of the QDs. Under optimized conditions, even the matrix-induced red shift of the emission upon incorporation can be overcome, resulting in a higher predictability of the mixed crystal preparation.

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Anomale Mischkristalle und orientierte Abscheidung

Cited by 40 publications

References 16 publications

Side Reactions in Aqueous Phase Polymerization of N‐Vinyl‐Pyrrolidone as Possible Source for Fouling

Side Reactions in Aqueous Phase Polymerization of N‐Vinyl‐Pyrrolidone as Possible Source for Fouling

Modeling of High‐Pressure Ethene Homo‐ and Copolymerization

QD-Salt Mixed Crystals: the Influence of Salt-Type, Free-Stabilizer, and pH

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