Macromolecular Reaction Engineering
Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Special Series: New Production and Enabling Technologies in Polymer Reaction Engineering
Guest-edited by Klaus-Dieter Hungenberg, this series publishes in an on-going fashion invited articles by leading researchers to document the rapid progress in this field.
Is Quantum Tunneling Relevant in Free-Radical Polymerization?Danilo Cuccato, Marco Dossi, Daniela Polino, Carlo Cavallotti, Davide Moscatelli*
Quantum tunneling is investigated on backbiting reactions active in the polymerization of ethylene, styrene, and vinyl chloride. The Eckart model is adopted to estimate tunneling factors and their dependence upon the temperature. The tunneling effect is found to be relevant in particular at the mild conditions typical of the free-radical polymerization of alkenes.
Macromol. React. Eng. DOI: 10.1002/mren.201200047
Investigating Cu(0)-Mediated Polymerizations: New Kinetic Insights Based on a Comparison of Kinetic Modeling with Experimental Data
Alexander P. Haehnel, Sven Fleischmann, Pascal Hesse, Klaus-Dieter Hungenberg, Christopher Barner-Kowollik*
The catalytic mechanism of Cu(0)-mediated polymerization is studied in detail with kinetic modeling underpinned by an experimental solvent polarity study. The density of the data points demonstrates that the commonly applied linear first-order kinetic analysis is not adequate. For some SET-LRP-specific rate coefficients, boundary values are defined that provide a well-controlled polymerization.
Macromol. React. Eng. DOI: 10.1002/mren.201200030
Modeling of Anionic Polymerization in Flow With Coupled Variations of Concentration, Viscosity, and DiffusivityBruno Cortese, Timothy Noel, Mart H.J.M. de Croon, Simon Schulze, Elias Klemm, Volker Hessel*
This paper explains the reasons behind the very low polydispersity index obtained in living anionic polymerizations in microstructured reactors. From the results, it can be explained that a narrow molecular weight distribution can be obtained due to the presence of a highly segregated flow behavior in microflow.
Macromol. React. Eng. DOI: 10.1002/mren.201200027
Mathematical Modeling of Acid-Catalyzed 1,3-Propanediol PolymerizationPhilipp A. Mueller,* Bhuma Rajagopalan, John P. Congalidis, Edward R. Murphy
This mechanism for the acid-catalyzed condensation polymerization of 1,3-propanediol to form poly(trimethylene ether glycol) is used to derive population balances for chain distributions. Upon coupling mass transfer to the kinetics, the fully predictive reaction model with a single set of parameters shows excellent agreement with the experimental data over a wide range of conditions.
Macromol. React. Eng. DOI: 10.1002/mren.201100069
Homogeneous Phase Copolymerizations of Vinylidene Fluoride and Hexafluoropropene in Supercritical Carbon DioxideEléonore Möller, Sabine Beuermann*
Copolymerizations of vinylidene fluoride and hexafluoropropene in supercritical carbon dioxide are reported. Reactions in homogeneous phase to complete vinylidene fluoride conversion were carried out in the absence of any surfactant or fluorinated auxiliary. The homogeneity and required pressures are strongly dependent on the hexafluoropropene content of the copolymers.
Macromol. React. Eng. DOI: 10.1002/mren.201000031
Homogeneous Polymerization: Benefits Brought by Microprocess Technologies to the Synthesis and Production of PolymersFlorence Bally, Christophe A. Serra,* Volker Hessel and Georges Hadziioannou
The benefits brought by microprocesses in the homogeneous synthesis of polymers over macroscale counterparts are reviewed. This includes, among others, a higher degree of control on the molecular weight distribution, the possibility for the polymerization to be performed at its kinetic limits and under new operating conditions; not to mention the modularity which allows for the synthesis of structurally controlled block copolymers.
Macromol. React. Eng. DOI: 10.1002/mren.201000006
A Hybrid Galerkin-Monte-Carlo Approach to Higher-Dimensional Population Balances in Polymerization KineticsChristof Schütte,* Michael Wulkow*
Today population balances arising from polymer reaction kinetics are treated either by deterministic algorithms or by Monte-Carlo methods with significant drawbacks on both sides. This paper shows how to combine their respective advantages by introducing a hybrid algorithm that simulates the chain-length distribution deterministically and additional property indices stochastically.
Macromol. React. Eng. DOI: 10.1002/mren.200900073
SP-PLP-EPR - A Novel Method for Detailed Studies into the Termination Kinetics of Radical PolymerizationJohannes Barth, Michael Buback*
Single pulse-pulsed laser polymerization-electron paramagnetic resonance (SP-PLP-EPR) has been introduced as a powerful method for the very detailed analysis of termination kinetics. During polymerization an intense laser pulse is applied in order to almost instantaneously produce a burst of radicals. The decay of radical concentration is measured by highly time-resolved EPR and is analyzed with respect to the rate coefficients for the termination of two radicals of identical size. SP-PLP-EPR experiments have been carried out for an itaconate monomer, for several methacrylates in bulk and in a solution of ionic liquids, for methacrylic acid in aqueous solution, and for the solution polymerization of butyl acrylate in toluene at low temperature. The data fully support the composite model, which assumes a stronger chain-length dependence of termination for radicals of smaller size and a weaker one for large radicals. The SP-PLP-EPR technique is also applicable in systems with more than one type of growing radicals, as is the case with butyl acrylate polymerization at higher temperature and with RAFT polymerizations, where the novel method may be used for a comprehensive kinetic analysis.
Macromol. React. Eng. DOI: 10.1002/mren.200900066
Prediction of Propagation Rate Coefficients in Free Radical Solution Polymerization Based on Accurate Quantum Chemical Methods: Vinylic and Related Monomers, Including Acrylates and Acrylic AcidPeter Deglmann,* Imke Müller, Florian Becker, Ansgar Schäfer, Klaus-Dieter Hungenberg, Horst Weiß
The simulation of polymerization processes is of enormous industrial importance. A quantum chemical method based on density functional theory is developed and validated that provides almost chemical accuracy for radical polymerization propagation of industrially relevant monomers in aqueous solution. The necessary corrections are computed using the CC level of theory. Solvent effects are accounted for by the solvation model COSMO-RS. The method is capable of reproducing and rationalizing, for example, monomer concentration effects on the propagation rate for NVP. A comparison is performed with recent PLP experimental data. The method does not rely on error compensation effects or empiric corrections and is suitable for industrially relevant systems.
Macromol. React. Eng. DOI: 10.1002/mren.200900034
Continuous ATRP Synthesis of Block-Like Copolymers via Column Reactors: Design and Validation of a Kinetic ModelBart Dervaux, Thomas Junkers, Christopher Barner-Kowollik,* Filip E. Du Prez*
A model for the block-like copolymerization via continuous supported ATRP was developed, enabling the calculation of the sequence distributions of the different monomers as a function of chain length in continuous flow reactors. Polydispersity indices, copolymer compositions, and complete molecular weight distributions could be predicted. The model was extensively tested under a wide range of reaction conditions and the outcome was compared with experimental data. An almost perfect match between the simulated and experimental kinetic data (first order kinetic plots, conversions, and PDI) was observed. A reasonable fit for the composition data of the copolymers was obtained. The influence of the flow rate in the column reactor on the copolymer composition was studied.
Macromol. React. Eng. DOI: 10.1002/mren.200900046
Microwave and Ionic Liquids: Inverse Temperature Dependence of Viscosity in Aqueous Medium of Grafted CopolymersElla Bezdushna, Helmut Ritter*
We elaborated a route to the thermosensitive polyelectrolyte system composed of 1-methyl-3-vinylimidazolium salt with -cyclodextrin complexed counterions and mono-(meth)acrylic functionalized poly(N-isopropylacrylamide) as grafted side chains via a three-step synthetic procedure. The aqueous solution of the polyelectrolyte displays partially inverse thermoresponsive behavior; it exhibits enhancement of shear viscosity up to body temperature. Furthermore, based on classically prepared poly(NIPAAm) bearing terminal amino groups, corresponding (meth-) acrylamide-type of macromonomers were easily obtained under microwave conditions.
Macromol. React. Eng. DOI: 10.1002/mren.200900018
FTIR Microscopy for Kinetic Measurements in High-Throughput Photopolymerization: Experimental Design and ApplicationPeter M. Johnson, Jeffrey W. Stansbury, Christopher N. Bowman*
Libraries with varying composition and exposure time were developed to enable high-throughput analysis of conversion using FTIR spectroscopy. This technique was demonstrated by measuring viscosity and backbone chain structure effects using four monomers: DPGDA, TEGDA, bisphenol-A-glycidyl diacrylate and ethoxylated bisphenol-A diacrylate. DPGDA has equivalent viscosity and double bond concentration with a shorter backbone chain length as compared to TEGDA. The ultimate conversion of TEGDA copolymerizations as compared to equivalent DPGDA copolymerizations is lowered from 15 to 5% due to differences in crosslink space chemistry and glass transition temperatures of the copolymer formulation.
Macromol. React. Eng. DOI: 10.1002/mren.200900029
Low Catalyst Concentration in a Tubular ReactorNicky Chan, Salima Boutti, Michael F. Cunningham*, Robin A. Hutchinson*
Continuous ARGET ATRP of butyl methacrylate was carried out in an 850 mL tubular reactor using parts per million levels of copper catalyst and stoichiometric amounts of ligand to copper under industrially relevant conditions without monomer and solvent purification. A copper(II) bromide/tris(2-pyridylmethyl)amine complex was used as catalyst, and tin(II) 2-ethylhexanoate was chosen as the reducing agent. It was found that stainless steel fittings and/or storage tanks had an adverse effect on polymerization rate, underlining the importance of the choice of chemically inert tubing. The problem of lower rate was solved by increasing the amount of reducing agent in the system fourfold, under which conditions the molecular weight development and polymerization rate in the tubular system compared well to that in a batch reactor. Thus, ARGET ATRP can be made significantly faster and more robust through the judicious use of an inexpensive and non-hazardous reducing agent. The tubular reactor produces polymer with a controlled molecular weight distribution continuously and reliably, demonstrating its potential for industrial adoption.
Macromol. React. Eng. DOI: 10.1002/mren.200900012
Dispersed Polymers in a Continuous Taylor-Couette ReactorGemma González, Eduardo Colmenar, Gabriela Diaconu, Felipe Alarcia, Mihaela Manea, María Paulis, Maria J. Barandiaran, José R. Leiza, José C. de la Cal, José M. Asua*
The suitability of a continuous Taylor-Couette reactor to produce widely different dispersed polymers was investigated. It was found that it is possible to synthesize high solids acrylic pressure sensitive adhesives prepared by conventional emulsion polymerization, with higher conversion and narrower particle size distribution than the one produced with a CSTR. Coagulum free acrylic-alkyd and acrylic-clay hybrid latexes synthesized by miniemulsion polymerization, with final particle size similar to the initial droplet size, were also obtained. The suitability of this reactor to synthesize flocculants obtained by inverse microemulsion polymerization was also demonstrated.
Macromol. React. Eng. DOI: 10.1002/mren.200900015
Special Article Series on 'New Production and Enabling Technologies in Polymer Reaction Engineering'Klaus-Dieter Hungenberg
It is about 30 to 40 years that 'Polymer Reaction Engineering' (PRE) became a scientific discipline of its own, thanks to the "forerunners" like Böhm, Hamielec, Ray, Reichert and Sinn. Since then, the polymer industry and also polymer research have changed dramatically.
Guest-edited by Klaus-Dieter Hungenberg (BASF SE), the new article series "New Production and Enabling Technologies in Polymer Reaction Engineering" will highlight the most important developments and trends in PRE. It is dedicated to research results on new and improved production technologies, but also to new developments in tools and enabling technologies.
Macromol. React. Eng. DOI: 10.1002/mren.200900027