Mf Maartje Kemmere

Sustainable polymer foaming using high pressure carbon dioxide: a review on fundamentals, processes and applications

In recent years, carbon dioxide (CO2) has proven to be an environmentally friendly foaming agent for the production of polymeric foams. Until now, extrusion is used to scale-up the CO2-based foaming process. Once the production of large foamed blocks is also possible using the CO2-based foaming process, it has the potential to completely replace the currently used foam production process, thus making the world-wide foam production more sustainable. This review focuses on the polymer–CO2-foaming process, by first addressing the principles of the process, followed by an overview of papers on nucleation and cell growth of CO2 in polymers. The last part will focus on application of the process for various purposes, including bulk polymer foaming, the production of bioscaffolds and polymer blends.

Supercritical Carbon Dioxide in Polymer Reaction Engineering

Foreword. Preface. List of Contributors. 1 Supercritical Carbon Dioxide for Sustainable Polymer Processes (Maartje Kemmere). 1.1 Introduction. 1.2 Strategic Organic Solvent Replacement. 1.3 Physical and Chemical Properties of Supercritical CO2. 1.4 Interactions of Carbon Dioxide with Polymers and Monomers. 1.5 Concluding Remarks and Outlook. 2 Phase Behavior of Polymer Systems in High-Pressure Carbon Dioxide (Gabriele Sadowski). 2.1 Introduction. 2.2 General Phase Behavior in Polymer/Solvent Systems. 2.3 Polymer Solubility in CO2. 2.4 Thermodynamic Modeling. 2.5 Conclusions. 3 Transport Properties of Supercritical Carbon Dioxide (Frederic Lavanchy, Eric Fourcade, Evert de Koeijer, Johan Wijers, Thierry Meyer, and Jos Keurentjes). 3.1 Introduction. 3.2 Hydrodynamics and Mixing. 3.3 Heat Transfer. 3.4 Conclusions. 4 Kinetics of Free-Radical Polymerization in Homogeneous Phase of Supercritical Carbon Dioxide (Sabine Beuermann and Michael Buback). 4.1 Introduction. 4.2 Experimental. 4.3 Initiation. 4.4 Propagation. 4.5 Termination. 4.6 Chain Transfer. 4.7 Conclusions. 5 Monitoring Reactions in Supercritical Media (Thierry Meyer, Sophie Fortini, and Charalampos Mantelis). 5.1 Introduction. 5.2 On-line Analytical Methods Used in SCF. 5.3 Calorimetric Methods. 5.4 MMA Polymerization as an Example. 5.5 Conclusions. 6 Heterogeneous Polymerization in Supercritical Carbon Dioxide (Philipp A. Mueller, Barbara Bonavoglia, Giuseppe Storti, and Massimo Morbidelli). 6.1 Introduction. 6.2 Literature Review. 6.3 Modeling of the Process. 6.4 Case Study I: MMA Dispersion Polymerization. 6.5 Case Study II: VDF Precipitation Polymerization. 6.6 Concluding Remarks and Outlook. 7 Inverse Emulsion Polymerization in Carbon Dioxide (Eric J. Beckman). 7.1 Introduction. 7.2 Inverse Emulsion Polymerization in CO2: Design Constraints. 7.3 Surfactant Design for Inverse Emulsion Polymerization. 7.4 Inverse Emulsion Polymerization in CO2: Results. 7.5 Future Challenges. 8 Catalytic Polymerization of Olefins in Supercritical Carbon Dioxide (Maartje Kemmere, Tjerk J. de Vries, and Jos Keurentjes). 8.1 Introduction. 8.2 Phase Behavior of Polyolefin-Monomer-CO2 Systems. 8.3 Catalyst System. 8.4 Polymerization of Olefins in Supercritical CO2 Using Brookhart Catalyst. 8.5 Concluding Remarks and Outlook. 9 Production of Fluoropolymers in Supercritical Carbon Dioxide (Colin D. Wood, Jason C. Yarbrough, George Roberts, and Joseph M. DeSimone). 9.1 Introduction. 9.2 Fluoroolefin Polymerization in CO2. 9.3 Fluoroalkyl Acrylate Polymerizations in CO2. 9.4 Amphiphilic Poly(alkylacrylates). 9.5 Photooxidation of Fluoroolefins in Liquid CO2. 9.6 CO2/Aqueous Hybrid Systems. 9.7 Conclusions. 10 Polymer Processing with Supercritical Fluids (Oliver S. Fleming and Sergei G. Kazarian). 10.1 Introduction. 10.2 Phase Behavior of CO2/Polymer Systems and the Effect of CO2 on Polymers. 10.3 Rheology of Polymers Under High-Pressure CO2. 10.4 Polymer Blends and CO2. 10.5 Supercritical Impregnation of Polymeric Materials. 10.6 Conclusions and Outlook. 11 Synthesis of Advanced Materials Using Supercritical Fluids (Andrew I. Cooper). 11.1 Introduction. 11.2 Polymer Synthesis. 11.3 Porous Materials. 11.4 Nanoscale Materials and Nanocomposites. 11.5 Lithography and Microelectronics. 11.6 Conclusion and Future Outlook. 12 Polymer Extrusion with Supercritical Carbon Dioxide (Leon P. B.M. Janssen and Sameer P. Nalawade). 12.1 Introduction. 12.2 Practical Background on Extrusion. 12.3 Supercritical CO2-Assisted Extrusion. 12.4 Mixing and Homogenization. 12.5 Applications. 12.6 Concluding Remarks. 13 Chemical Modification of Polymers in Supercritical Carbon Dioxide (Jesse M. de Gooijer and Cor E. Koning). 13.1 Introduction. 13.2 Brief Review of the State of the Art. 13.3 End-group Modification of Polyamide 6 in Supercritical CO2. 13.4 Carboxylic Acid End-group Modification of Poly(Butylene Terephthalate) with 1,2-Epoxybutane in Supercritical CO2. 13.5 Concluding Remarks and Outlook. 14 Reduction of Residual Monomer in Latex Products Using High-Pressure Carbon Dioxide (Maartje F. Kemmere, Marcus van Schilt, Marc Jacobs, and Jos Keurentjes). 14.1 Introduction. 14.2 Overview of Techniques for Reduction of Residual Monomer. 14.3 Enhanced Polymerization in High-Pressure Carbon Dioxide. 14.4 Extraction Capacity of Carbon Dioxide. 14.5 Process Design for the Removal of MMA from a PMMA Latex Using CO2. 14.6 Conclusion and Future Outlook. Subject Index.

Calorimetric study of the energy efficiency for ultrasound-induced radical formation.

Energy conversion in sonochemistry is known to be an important factor for the development of industrial applications, however, the strong influence of the physical properties of the liquid on the ultrasound characteristics usually prevents an accurate determination of the chemical effects. In this study, the energy efficiency of the ultrasound-induced radical formation from methyl methacrylate has been investigated. The energy yield can be quantified by comparison of the ultrasonic power that is transferred to the liquid and the radical formation kinetics. Based on this method the influence of temperature and amplitude of the ultrasound horn on the energy efficiency has been determined. The energy yield for the formation of radicals from ultrasonic waves appears to be in the order of 5 x 10(-6) J/J. The energy conversion is the highest at low temperatures and at low amplitudes.

A model for the coagulation of polyvinyl acetate particles in emulsion

In the present work we develop a mathematical model for the coagulation of polymer particles in emulsion polymerization systems. The model considers a Brownian coagulation kernel and assumes that interactions between particles can be described through the DLVO theory, where the presence of a Stern layer is accounted for. The model is then compared with experimental data for the coagulation of monomer swollen polyvinyl acetate particles, carried on with three different seeds at various operating conditions, showing in all cases a satisfactory agreement.

Externally Triggered Glass Transition Switch for Localized On‐Demand Drug Delivery

want a new drug dose: External on-demand laser triggering is used in a drug-delivery concept, with on/off ratios in excess of 1000/1. The switching mechanism involves the glass transition of hydrophobic polymers with a large change in diffusivity. Formation of a glassy surface layer of the implant in the off state plays a key role, resulting in negligible off-release. (Picture: data points indicate ibuprofen concentration).

Aspects of coagulation during emulsion polymerization of styrene and vinyl acetate

The influence of recipe and process conditions on the coagulation behavior of polystyrene (PS) and polyvinyl acetate (PVAc) latices has been studied. Seeded batch experiments reveal a significant influence of electrolyte concentration on the coagulation behavior of both PS and PVAc latices. Within the experimental error, no dependency of the coagulation behavior on process conditions, in terms of energy dissipation, reactor scale, impeller type, and impeller diameter, has been observed for the reactor scales investigated. These results indicate that intrinsic chemical influences such as electrolyte concentration dominate the coagulation behavior during emulsion polymerization and also in the absence of polymerization over the process conditions.

A novel process for the catalytic polymerization of olefins in supercritical carbon dioxide

A novel process is being developed for the catalytic polymerization of olefins in supercritical carbon dioxide. Potential applications will mainly be in the production of EPDM and other elastomers. For this purpose, catalysts have been synthesized and tested. Late transition metal-based catalysts of the Brookhart type have been used to polymerize 1-hexene and ethylene in supercritical CO2 yielding high molecular weight polymers. Additionally, polymerizations of 1-hexene in CH2Cl2 have been performed as reference experiments. In the case of 1-hexene, a comparison with the polymerization behavior in CH2Cl2 reveals similar molecular weights and molecular weight distributions. Furthermore, the multicomponent phase behavior of polymer systems at supercritical conditions has been studied. The phase behavior of binary and ternary systems containing poly(ethylene-co-propylene), ethylene and CO2 has been determined experimentally by measuring cloud-point isopleths. The predictions of the phase behavior as obtained from statistical associated fluid theory calculations agree very well with the experimentally determined cloud-points. Based on these results, some important aspects for the process design have been addressed, for which catalyst solubility, efficient recycle of CO2 and purification of the polymer product are key issues.

Rheology and flow during high solids emulsion polymerization of styrene

ABSTRACTCommercial emulsion polymerization processes are often carried out with high solids (50 percent monomer by weight) recipes, resulting in relatively viscous, pseudo-plastic reaction mixtures. The change in rheological behavior during high solids emulsion polymerization complicates the process operation in terms of imperfect mixing and reactor fouling.This paper discusses the rheology and flow during high solids emulsion polymerization of styrene, as well as the effect of particle size distribution.

Emulsification in batch emulsion polymerization

Dispersion of liquid–liquid systems is often applied in industrial processes such as extraction, suspension, and emulsion polymerization. The influence of emulsification of the monomer in the aqueous phase on the course and outcome of the batch emulsion polymerization of styrene has been studied. A visual criterion was applied for determining the lowest impeller speed for sufficient emulsification (N*). It appeared that in polymerization experiments under the same conditions, N* was the critical value above which no further increase in polymerization rate was observed. Using a turbine impeller instead of a pitched blade impeller as well as using a larger impeller diameter provides better emulsification at constant power input. The results indicate that scale-up with constant impeller tip speed is most appropriate in case of a turbine impeller.

Repetitive on-demand drug release by magnetic heating of iron oxide containing polymeric implants

Drug release from a polymeric matrix has been externally triggered using an alternating magnetic field in order to develop an on-demand drug delivery implant. Superparamagnetic iron oxide nanoparticles have been distributed in a poly(methyl methacrylate) core, coated with a thermoresponsive layer of poly(butyl methacrylate-stat-methyl methacrylate) containing ibuprofen as a model drug. The release rate of ibuprofen reversibly increased, up to 25-fold, upon exposure to the magnetic field and was found to increase with higher iron oxide loading. Finally, magnetically triggered on-demand drug release was demonstrated under physiologically relevant conditions, namely 37 °C in PBS buffer with high ibuprofen content in the implant and only 15 minutes triggering time.