Macromolecular Reaction Engineering

Cover image for Vol. 8 Issue 7

Early View (Online Version of Record published before inclusion in an issue)

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  1. Full Papers

    1. Achieving High-Conversion Bulk ATRP with Good Livingness and Well Controlled by Design and Optimization of Polymerization Temperature Profile

      Ali Mohammad Rabea and Shiping Zhu

      Article first published online: 28 JUL 2014 | DOI: 10.1002/mren.201400019

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      Bulk ICAR ATRP of MMA is carried out up to high conversions. By means of optimization of the ICAR rate by a predesigned temperature profile, well-controlled polymer molecular weights are achieved. Polymers of PDI < 1.3 with initiator efficiencies close to 100% are obtained up to 98% conversion. Chain extension experiments confirm the livingness of the final products.

    2. Modeling the Kinetics of Monolith Formation by RAFT Copolymerization of Styrene and Divinylbenzene

      Porfirio López-Domínguez, Julio César Hernández-Ortiz, Kristine J. Barlow, Eduardo Vivaldo-Lima and Graeme Moad

      Article first published online: 26 JUN 2014 | DOI: 10.1002/mren.201400013

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      The production of RAFT-based poly(styrene-co-divinylbenzene) monoliths is successfully modeled using a multifunctional polymer molecule approach. The inclusion of diffusion-controlled effects can produce feasible simulations, but non-isothermal effects in the reacting tubes may have to be taken into account in further refinements to the model.

    3. Acrylic–Alkyd Hybrids: Secondary Nucleation, Particle Morphology, and Limiting Conversions

      Ravindra Udagama, Carolina de las Heras Alarcón, Joseph L. Keddie, John G. Tsavalas, Elodie Bourgeat-Lami and Timothy F. L. McKenna

      Article first published online: 25 JUN 2014 | DOI: 10.1002/mren.201400003

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      The polymerization of miniemulsions of acrylic monomer/alkyd mixtures is studied. It is shown that complete conversion can only be obtained if secondary nucleation is allowed to occur at high alkyd contents. In addition, it is demonstrated that the choice of initiator can have a significant impact on particle morphology and the quality of the resulting films.

    4. RAFT Ab Initio Emulsion Polymerization of Styrene Using Poly(acrylic acid)-b-polystyrene Trithiocarbonate of Various Structures as Mediator and Surfactant

      Jie Huang, Shuai Zhao, Xiang Gao, Yingwu Luo and Bogeng Li

      Article first published online: 25 JUN 2014 | DOI: 10.1002/mren.201400010

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      Ab initio emulsion polymerization of styrene using the AAx-b-Sty macroRAFT as both mediator and surfactant is investigated by varying x and y values in a systematic way. The polymerization is well-controlled in terms of little coagulum and low PDI by using KPS as initiator but the experimental inline image s deviate from the theoretical values according to different HLB values due to the oxidization. Replacing KPS with V501 as initiator, inline image is in excellent agreement with the theoretical predictions, however with higher PDI.

  2. Communication

    1. Effect of Agitation on Density of Poly(vinyl acetate) Particles Produced in Suspension Polymerization Reactions

      Felipe B. Cordeiro, Luciana S. Peixoto, Marco A. M. Oliveira and José Carlos Pinto

      Article first published online: 18 JUN 2014 | DOI: 10.1002/mren.201400017

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      Hollow particles formed through vinyl acetate suspension polymerization are shown containing smaller sub-particles, due to the encapsulation of water when the agitation speed is sufficiently high, which can explain the variation of polymer density with modification of the agitation speed.

  3. Full Papers

    1. Kinetic Features of Hexene-1 Polymerization over Supported Titanium–Magnesium Catalyst

      Ludmila Echevskaya, Mikhail Matsko, Marina Nikolaeva, Sergei Sergeev and Vladimir Zakharov

      Article first published online: 18 JUN 2014 | DOI: 10.1002/mren.201400009

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      Cocatalyst composition has a strong effect on the molecular mass and MWD of polyhexene produced over a high-activity and high-stereospecificity titanium–magnesium catalyst. This effect is attributed to the formation of polyhexene in solution in comparison with slurry polymerization of ethylene and propylene.

  4. Special Article Series - Full Papers

    1. Kinetics and Growth of Polyethylene Nanofibrils over Metallocene Catalyst Supported on Flat Silica and Spherical Nano-Silica Particles

      Sang Yool Lee and Kyu Yong Choi

      Article first published online: 18 JUN 2014 | DOI: 10.1002/mren.201400018

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      A catalyst loaded flat silica surface is deposited with methylaluminoxane (MAO) and a rac-Et(indenyl)2ZrCl2 catalyst. The polymer grows as nanofibrils of about 30–45 nm diameter. Some MAO clusters are formed and catalytic sites are concentrated in these clusters. The flat silica supported catalyst exhibit highest catalytic activity.

  5. Full Papers

    1. New Quenching Method for Improving Large-Scale Stopped-Flow Technique

      Ashutosh Thakur, Supawadee Poonpong, Minoru Terano and Toshiaki Taniike

      Article first published online: 18 JUN 2014 | DOI: 10.1002/mren.201400014

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      A new quenching method is successfully introduced to enhance the scalability of the stopped-flow polymerization using Ziegler-Natta catalysts. The modification enables stopped-flow polymerization over 2 000 mL of the flow volume to endow a sufficient amount of polymer even in an initial stage.

    2. In-Situ Incorporation of Poly(methyl methacrylate) in Suspension Styrene Polymerizations

      Carlos A. Castor, Márcio Nele and José Carlos Pinto

      Article first published online: 11 JUN 2014 | DOI: 10.1002/mren.201400007

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      Optical micrographs of PS particles containing 10 wt% of PMMA and produced through free-radical suspension polymerization.

    3. Bulk Crosslinking Copolymerization: Comparison of Different Modeling Approaches

      Stefano Lazzari, Shaghayegh Hamzehlou, Yuri Reyes, Jose Ramon Leiza, Mário Rui P. F. N. Costa, Rolando C. S. Dias and Giuseppe Storti

      Article first published online: 5 JUN 2014 | DOI: 10.1002/mren.201400005

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      The present paper compares the predictions of different modeling approaches on a bulk crosslinking copolymerization scheme. Models based on average properties match the predictions of more detailed models in terms of average predictions, but not for chain length distributions. As a result, guidelines for the most-suitable usage of such models are provided.

    4. Branched and Crosslinked Polymers Synthesized through NMRP: Quantitative Indicators for Network Homogeneity?

      Alison J. Scott, Afsaneh Nabifar and Alexander Penlidis

      Article first published online: 19 MAY 2014 | DOI: 10.1002/mren.201400004

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      Characterization of branched and crosslinked polystyrene/divinylbenzene samples, synthesized via nitroxide-mediated radical polymerization, is presented. Techniques including size exclusion chromatography and thermo-mechanical analysis are used in an attempt to quantify the homogeneity of the polymer network. Ultimately, this work attempts to verify experimentally the literature claim that controlled radical polymerization will result in a more homogeneous network than free radical polymerization.

    5. Flow Inversion: An Effective Means to Scale-Up Controlled Radical Polymerization Tubular Microreactors

      Dambarudhar Parida, Christophe A. Serra, Dhiraj K. Garg, Yannick Hoarau, René Muller and Michel Bouquey

      Article first published online: 9 MAY 2014 | DOI: 10.1002/mren.201400002

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      The concept of coil flow inversion (CFI) is introduced in ATRP coiled tube microreactors (CT) to increase the throughput. Flow inversion allows alleviating the detrimental effect of increase in reactor diameter on polymer characteristics. By increasing the reactor inner diameter from 876 μm to 4 mm and reducing the length by half, a tenfold increase in throughput is achieved with no significant increase in PDI.

    6. Hydrolytic Caprolactam Polymerization – Progress in Dynamic Simulation

      Johannes Katzer

      Article first published online: 9 MAY 2014 | DOI: 10.1002/mren.201400006

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      Although it is known for almost a century and thoroughly investigated for decades now, the seemingly simple use of multifunctional acids as stabilizers during hydrolytic caprolactam polymerization still raises problems. Therefore, reliable models implementing the impact on the molecular weight distribution during dynamic simulation have not yet been published. This article tries to fill the gap and supports to enable targeted product design for polyamide 6 and other polymers.

    7. Particle Behavior in FBRs: A Comparison of the PBM–CFD, Multi-Scale CFD Simulation of Gas–Solid Catalytic Propylene Polymerization

      Ya-Ping Zhu, Guo-Qiang Chen and Zheng-Hong Luo

      Article first published online: 20 MAR 2014 | DOI: 10.1002/mren.201300196

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      A multi-scale CFD has been developed to describe the particle behavior in a polymerization FBR. The multi-scale model is tested by comparing simulation results with experimental data. The simulations demonstrate that both the intraparticle mass and heat transfer significantly impact the particle behavior.

    8. Modeling of the Production of Hydrogels from Hydroxyethyl Methacrylate and (Di)Ethylene Glycol Dimethacrylate in the Presence of RAFT Agents

      Lizeth Espinosa-Pérez, Julio César Hernández-Ortiz, Porfirio López-Domínguez, Gabriel Jaramillo-Soto, Eduardo Vivaldo-Lima, Patricia Pérez-Salinas, Alberto Rosas-Aburto, Angel Licea-Claverie, Humberto Vázquez-Torres and Maria Josefa Bernad-Bernad

      Article first published online: 13 FEB 2014 | DOI: 10.1002/mren.201300191

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      The growth of hydrogels from HEMA and EGDMA (or DEGDMA) with controlled structures is studied with the aid of a comprehensive mathematical model previously developed by us. Bulk and solution copolymerizations are addressed and the bulk situation is used to approximate the behavior of a RAFT dispersion copolymerization of HEMA/EGDMA in scCO2.

    9. Preparation of PMMA-b-PSt Block Copolymer via Seeded Emulsion Polymerization in the Presence of 1,1-Diphenylethylene

      Minjian Zhao, Yan Shi, Zhifeng Fu and Wantai Yang

      Article first published online: 17 JAN 2014 | DOI: 10.1002/mren.201300174

      Thumbnail image of graphical abstract

      The behavior of methyl methacrylate in emulsion polymerization in the presence of 1,1-diphenylethylene is investigated by the analysis of instantaneous number MWD. The block copolymer PMMA-b-PSt is successfully prepared by simply heating the PMMA seed emulsion controlled by DPE in the presence of second monomer St.

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