Emulsion Copolymerization Process Research Articles

Digital Twin for the SBR Cold Emulsion Copolymerization Process

AbstractDevelopment of accurate and robust dynamic models for the description of emulsion copolymerization processes is fundamental for the implementation of monitoring, advanced control, and optimization strategies. There are several studies on the dynamic modeling of styrene/1,3‐butadiene rubber (SBR) emulsion copolymerization, but most of them focus on hot conditions or only one semi‐batch reactor, as in the case of cold conditions. For this reason, the present study focuses on the dynamic modeling of SBR cold emulsion copolymerization processes considering a train of 15 continuous stirred tank reactors, as in many real industrial sites. The developed dynamic model is implemented by using the digital twin (DT) concept, which involves the online reading of process variables and an adaptive strategy for online tuning of some of the model parameters, being also sensitive to the effect of real‐time changes on the number of reactors in the train, a subject that has been overlooked previously, but which is important at the plant site. The practical application of the DT for monitoring a real industrial process illustrates the robustness and accuracy of the developed tool, making it useful for opportune detection of process anomalies and opening the way for future advanced control strategies.

Enhancing MRI through high loading of superparamagnetic nanogels with high sensitivity to the tumor environment

A novel γ-Fe2O3@PNIPAm/PAm/CTS hybrid nanogel using a surfactant-free emulsion copolymerization process exhibited temperature- and pH-sensitivity, enabling magnetic targeting and enhancing diagnosis through MRI.

Dynamic optimization of an emulsion copolymerization process for product quality using a deterministic kinetic model with embedded Monte Carlo simulations

We present the dynamic optimization of an emulsion copolymerization process described by a deterministic kinetic ordinary differential equation model including a stochastic Monte Carlo submodel, describing the growth of polymer chains within particles. For the considered semi-batch operation, the time dependent input trajectories for monomer and initiator flow rates are optimized along with the isothermal reactor temperature. We use the surrogate-model-based optimizer MATSuMoTo for the optimization to avoid the need to compute derivatives of the stochastic model. Radial basis functions with linear polynomial tails are selected as surrogate functions which are updated during optimization by the newly evaluated points. A relevant application problem formulation together with results for two case studies are presented. Qualitatively similar input trajectories are obtained for different optimization runs due to the stochastic process and the limited number of iterations. All solutions reduce the batch time significantly.

Base case simulation of a semi-batch emulsion copolymerization process: application to styrene/ butadiene system

It has been long recognized that emulsion polymerization is a complex heterogeneous process involving transport of monomers, free radicals, and other species between aqueous phase and organic phase. Though there are a number of models available in the literature, most of them deal only with specific aspects in emulsion polymerization and are far from being general. To simulate this complicated process and to achieve an adequate level of understanding, a Polymers Plus software from Aspen Technology. Inc. was used. The objective of this work is to illustrate the principle of use of Polymers Plus, simulate, and analyze the free-radical seeded emulsion copolymerization of styrene­butadiene process model in a semi-batch reactor. The base case simulation can be used to gain process understanding by analyzing how process variables and operating conditions during the course of a semi-batch reactor affect the product quality.Keywords: Polymers Plus, Emulsion Copolymerization, Simulation, Semi Batch Reactor, Styrene/ butadiene AbstrakTelah diketahui sejak lama bahwa polimerisasi emulsi merupakan sebuah proses heterogen yang kompleks, yang meliputi perpindahan monomer, radikal bebas, dan senyawa lainnya dalam fasa air dan fasa organik. Walaupun dalam literatur terdapat berbagai model, sebagian besar hanya membahas tentang aspek-aspek khusus dalam polimerisasi emulsi yang belurn berlaku umum. Untuk melakukan simulasi serta meningkatkan pemahaman tentang proses yang kompleks ini, digunakan perangkat lunak Polymers Plus dari Aspen Technology, Inc. Penelitian ini bertujuan untuk memberikan ilustrasi tentang prinsip penggunaan Polymers Plus serta melakukan simulasi dan analisis tentang model untuk proses kopolimerisasi emulsi styrene-butadiene dengan free radical seeded dalam reaktor semi batch. Simulasi ini dapat digunakan untuk memperoleh pemahaman proses dengan menganalisis pengaruh variabel-variabel proses dan kondisi operasi dalam reaktor semi batch terhadap kualitas produk.Kata Kunci: Polymers Plus, Kopolimerisasi Emulsi, Simulasi, Reaktor Semi Batch, Stiren/ butadien

Continuous emulsion copolymerization processes at mild conditions in a 3D-printed tubular bended reactor

A polylactic acid tubular bended reactor, printed by fused deposition modeling with a short and narrow residence time distribution, air-cooled, and with dead volumes below 5 vol% was integrated into a modular reaction system enabling product changes in the running system. Continuous, redox-initiated emulsion copolymerizations of styrene - butyl acrylate and of vinyl acetate - neodecanoic acid vinyl ester were successfully performed with 20 and 40 wt% monomer in the feed. Copolymerizations had an ambient starting temperature with a mean residence time of 5 and 15 min, conversions were between 81 and 99%. The resulting emulsions were stable with Zeta potential values up to –132.0 mV and no product adhesion to the reactor wall was found. A stable steady state of the reaction plant was also obvious from thermal imaging, showing an invariant temperature profile along the 3D-printed reactor. The high versatility of the reactor system was shown by a grade transition between the copolymer systems with 20 wt% monomer content.

Multi-model approach based on parametric sensitivities – A heuristic approximation for dynamic optimization of semi-batch processes with parametric uncertainties

Abstract Optimal processes often exhibit active path constraints. Parametric uncertainties in the process model might thus lead to constraint violations. A heuristic approach is presented to overcome this challenge. The nominal model is optimized with additional path constraints due to worst-case models. A heuristic method of choosing these models is proposed based on sensitivities of the constraints with respect to the uncertain parameters. The presented approximation does not guarantee robust feasibility, but path constraint violations are less likely to occur compared to the optimization using the nominal model solely. Two case studies are presented: a complex emulsion copolymerization process (DAE with 139 equations) and the penicillin formation (four differential equations and two algebraic equations). The results of both case studies show that, in contrast to the optimization in the nominal case, the multi-model approach does not violate the path constraints for different scenarios of the parametric uncertainty set.

Emulsion copolymerization of substituted acetylenes for constructing optically active helical polymer nanoparticles. Synergistic effects and helicity inversion

ABSTRACTCopolymerizations of substituted acetylenes have been intensively studied in solution polymerization for constructing chirally helical polymers, while emulsion copolymerizations of the kind of monomers have been only scarcely reported. In the present study, chiral substituted acetylene monomer containing cholic acid group underwent emulsion copolymerizations with an achiral acetylenic monomer in the presence of rhodium catalyst, providing optically active helical copolymer nanoparticles. Synergistic effects were found in the resulting helical copolymers, enabling one certain copolymer to show the maximum CD signal intensity. Moreover, the helicity of the helical copolymers in nanoparticle state was opposite to that in solution state. This is the first demonstration that synergistic effects and helicity inversion simultaneously occurred in helical copolymers prepared by emulsion copolymerization process. To deepen the understanding of the unique phenomena, corresponding solution copolymerization and emulsification process were also investigated. Different from “Sergeant and Soldiers rule” approach, the present study provides a new strategy for preparing chirally helical polymer particles by making full use of achiral monomers. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 1679–1685

Mathematical Modeling of 1,3-Butadiene and Methyl Methacrylate Emulsion Copolymerization Process

A mathematical model for emulsion copolymerization process of 1,3-butadiene and methyl methacrylate is presented and validated with experimental data in a batch reactor. The model is able to explain the effects of changes in temperature, monomer-to-water ratio, emulsifier concentration, initiator concentration, and monomer feed composition on the time evolution of monomer conversion, average particle size, and pressure. Despite its simplicity and a reduced number of adjustable parameters, the model is capable of accounting for the basic features of emulsion copolymerization processes and can be used in engineering applications.

Sequence Distribution and Cumulative Composition of Gradient Latex Particles Synthesized by a Power-Feed Technique

Nonuniform latex particles, with a gradient change in composition between molecular chains, were prepared using a power-feed technique. The feed program of the addition process was quantitatively analyzed, and the corresponding equations were derived. A simple dropwise analysis model was established to simulate the sequence distribution and cumulative composition of gradient latex particles based on traditional free radical copolymerization. This model avoided consideration of the detailed kinetic procedure with great uncertainties in an emulsion polymerization. The apparent reactivity ratio of methyl methacrylate (MMA) and n-butyl acrylate (BA) during the emulsion copolymerization process, which was first measured by utilizing K-T, YBR, and other methods, and together with the conversion function, were used as the model parameters. 1H NMR and 13C NMR were used to characterize the experimental sequence distribution and cumulative composition to verify the model. The simulation results are in good agreemen...

Modeling and Simulation of an Emulsion Copolymerization Process

Modeling and Simulation of an Emulsion Copolymerization Process

Synthesis of biobased multivalent cross-linkers from a castor oil-derived C22-acyloin

A number of interesting biobased chemical building blocks were developed via the condensation of the C22 acyloin obtained from 10-undecenoic acid (castor oil and a non-edible oil) with mono- and bifunctional acid chlorides. Two terminally unsaturated acid chlorides (C3 and C11), three long chain saturated aliphatic acid chlorides (C10, C12 and C14), as well as the bifunctional adipoyl chloride were used. The condensation products were obtained as pure oils with potential cross-linking features and are therefore of interest as biobased crosslinkers for the polymer industry. The acyloin was successfully copolymerized in a radical emulsion copolymerization process, replacing diallyl phthalate. Radical, ionic or coordination homopolymerization of the same acyloin, however, did not work. Neither did the radical homopolymerization of undecenoyl acyloin. The acrylated acyloin, however, was transformed into a transparent glass upon solvent-free radical polymerization initiated by benzoyl peroxide. Thermogravimetric, Differential Scanning Calorimetry and Dynamic Mechanical Analyses were performed on the obtained polymer. Epoxidation of the triple unsaturated undecenoyl acyloin and the acyloin itself was evaluated as well.

Polymer photonic crystal band-gap modulation using PbS quantum dots

This study aims to present the manufacture of polymer photonic crystals (PCs) and the study of the influence of PbS quantum dots on their optical properties. Monodisperse latexes resulting from the polymerization of styrene and acrylic acid were obtained by a soap-free emulsion copolymerization process and their optical response was modified using PbS high refractive index nanoparticles. A stop-band modulation was achieved by controlling the nanoparticles concentration that resulted in the altering of the self-assembly process. Thus, at low PbS concentrations, a blue-shift of the band-gap was registered, whereas at high concentrations, a red-shift was measured. The hybrid materials were investigated by DLS, SEM, HRTEM, UV-VIS and XRD analyses.

Synthesis of styrene–acrylamide copolymer by surfactant‐free sonicated dynamic interfacial polymerization

This paper summarizes a study on emulsifier‐free ultrasonically assisted in situ dynamic interfacial emulsion copolymerization process of acrylamide and styrene. The resulting emulsions are stable and uniform for several months. Thermogravimetric analysis (TGA) curves and reaction conversion measurements have provided an important knowledge regarding the emulsifier‐free polymerization method. Solvent extractions (water, methanol, and xylene) have shown that the polymerization product is essentially a styrene–acrylamide copolymer. The copolymer produced is a block copolymer, PS‐b‐PAM, where each block contains small amounts of the other comonomer. The produced emulsions are film forming at room temperature in spite of the very high block Tgs, owing to a unique water plasticization effect of the polyacrylamide blocks. Some films prepared from the PS‐b‐PAM have resulted in clear and transparent films. The presented interfacial dynamic polymerization process is fast, reaching 81% conversion within 2 hr of sonication at 4°C (low temperature owing to molecular weight and kinetic considerations), and produces very stable PS‐b‐PAM emulsions. TGA was extensively used as an analytical tool for determination of the reaction parameters and composition of the acrylamide–styrene copolymers. Copyright © 2011 John Wiley & Sons, Ltd.

Modeling and Multiobjective Optimization of A Fed‐Batch Emulsion Copolymerization Process to Control the Resulting Particles Core‐Shell Morphology

AbstractSummary: This paper deals with the design and control of the morphology of core‐shell nanoparticles elaborated by fed‐batch emulsion copolymerization of styrene and butyl‐acrylate in the presence of a chain transfer agent (n‐dodecyl mercaptan). A mathematical model was elaborated and validated. It consists of a system of differential algebraic equations involving 49 unknown kinetic and thermodynamic parameters, many of them being impossible to be accurately estimated, due to the lack of experimental data. A method based on the sensitivity analysis allowed us to determine a subset of the 21 most influential parameters. The 28 non estimable parameters were taken from the literature. The validated model was then used in a dynamic multiobjective optimization to optimize the best profile of the pre‐emulsion feed rate to control (i) the composition and average molar masses of the copolymer, (ii) the instantaneous glass transition temperature, corresponding to a core‐shell morphology suited for special end‐use properties.

Upon the emulsion polymerization of 2-hydroxyethyl methacrylate with 3,9-divinyl-2,4,8,10-tetraoxaspiro[5.5]-undecane

The radical emulsion copolymerization process between 2-hydroxyethyl methacrylate and 3,9-divinyl-2,4,8,10-tetraoxaspiro[5.5]-undecane, an acetal-type crosslinking agent comonomer, it is presented. The conversion, polymerization rate, particle size and zeta potential were investigated. It was found that the presence of the crosslinking agent comonomer determines the slowly decrease of the conversion. As it was expected the addition of the crosslinking agent determines the increase of the hydrodynamic diameter and the decrease of the zeta potential and the conductivity. The copolymer formation was confirmed by FT-IR and 1H NMR spectroscopy. It was also evidenced that the cycle (tetraoxaspiro) is not opened during the polymerization process. The copolymer composition recommends the prepared compounds as biomaterials. Also, owing to the tetraoxaspiro cycle presence the synthesized copolymeric network degrades in the acid medium allowing its use for future drug delivery systems applications.

Development of new concepts for the control of polymerization processes: Multiobjective optimization and decision engineering. II. Application of a Choquet integral to an emulsion copolymerization process

AbstractIn polymer industry, engineers seek to obtain polymers with prescribed end‐use properties, high productivities, and low cost. Thus, the optimization of a manufacturing process with all those goals and constraints belongs to a problem domain that aims to achieve the best trade‐off possible. This article concerns the optimization of the batch emulsion polymerization of styrene and α‐methylstyrene. An accurate model was developed to describe the complete patterns of the emulsion polymerization. Key parameters of the model were identified on the basis of batch experimental data. The model was then used to simulate, under several operating conditions, the polymerization rate, the overall conversion of monomers, and the number and weight‐average molecular weights. Amulticriteria optimization approach based on an evolutionary algorithm and the concept of dominance from the Pareto frontier theory was used. Last, a decision aid system based on the Choquet integral was proposed to determine the optimal operating conditions with the preferences of the decision maker taken into account. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Modeling Vinyl Acetate and n‐Butyl Acrylate Emulsion Copolymerization Process

AbstractThis work presents a mathematical model for the vinyl acetate and n‐butyl acrylate emulsion copolymerization process in batch reactors. The model is able to explain the effects of simultaneous changes in emulsifier concentration, initiator concentration, monomer‐to‐water ratio, and monomer feed composition on monomer conversion, copolymer composition and, to lesser extent, average particle size evolution histories. The main features of the system, such as the increase in the rate of polymerization as temperature, emulsifier, and initiator concentrations increase are correctly represented by the model. The model accounts for the basic features of the process and may be useful for practical applications, despite its simplicity and a reduced number of adjustable parameters.

Development of a Continuous Emulsion Copolymerization Process in a Tubular Reactor

This contribution describes the development of a continuous emulsion copolymerization processs for vinyl acetate and n-butyl acrylate in a tubular reactor. Special features of this reactor include the use of oscillatory (pulsed) flow and internals (sieve plates) to prevent polymer fouling and promote good radial mixing, along with a controlled amount of axial mixing. The copolymer system studied (vinyl acetate and butyl acrylate) is strongly prone to composition drift due to very different reactivity ratios. An axially dispersed plug flow model, based on classical free radical copolymerization kinetics, was developed for this process and used successfully to optimize the lateral feeding profile to reduce compositional drift. An energy balance was included in the model equations to predict the effect of temperature variations on the process. The model predictions were validated with experimental data for monomer conversion, copolymer composition, average particle size, and temperature measured along the reactor length.

Preparation of acrylic copolymer latex modified by fluorine, silicon, and epoxy resin

AbstractA series of modified acrylic copolymer latices have been prepared through a semicontinuous emulsion copolymerization process with a variety of hydrocarbon monomers and (perfluoroalkyl) methyl methacrylate, vinyltriethoxysilicone, and phenol‐formaldehyde epoxy resin. The composition of copolymer was analyzed by fluoride ion selective electrode analysis, 19F NMR, FTIR, crosslinking degree determination, and epoxy‐acetone method. The results showed that the fluorine monomer, silicon monomer and epoxy resin had copolymerized with acrylic monomers. The optimum mass ratio between the curing agent TEA and epoxy resin was 1.36 : 6. The determination results of stabilities (electrolyte stability, freeze‐thaw stability, high temperature stability and mechanical stability) of latices showed that the incorporation of fluorine monomer and silicon monomer improved freeze‐thaw stability and mechanical stability, whereas the epoxy resin did not have obvious effect on the stabilities. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Synthesis of a latex with bimodal particle size distribution for coating applications using acrylic monomers

Multipart emulsion polymerization of methyl methacrylate (MMA) and butyl acrylate (BA) was carried out in this work. The target was to achieve stability during the polymerization and to determine the proper hydrophilic–lipophilic balance (HLB) value for the stable system, using different types of non-ionic emulsifiers, sodium lauryl sulphate and their combinations. After determination of proper value of HLB (36.2), the best emulsifier combination on the basis of minimization of coagulum level was determined. This combination was 20 wt.% of KENON30 to SLS. The effect of monomer feed composition on the dry latex film properties was investigated to approach a monomer feed composition dealt with a proper T g. The prepared latex showed a bimodal particle size distribution, due to the proper feeding policy in semibatch emulsion copolymerization process. The monomer feed composition of 45 wt.% MMA and 55 wt.% BA with a proper T g was selected for the final improvement of coating properties such as UV resistance and adhesion. Adding acrylic acid (AA) and N-methylol acrylamide (NMA) to the reaction mixture improved the UV resistance and adhesion property of dry latex film. The flow and leveling, gloss, adhesion, UV resistance and water resistance of the produced bimodal latex showed good quality in comparison with the similar commercial resins used in coating applications.