Macromolecular Reaction Engineering

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

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  1. Full Papers

    1. CFD Derived Results Lead to An Installation of An Overflow Technique in A Microreactor for Gas-Phase Ethene Homo Polymerization

      Leonhard Mayrhofer, Apostolos Krallis, Christof Wurnitsch and Christian Paulik

      Article first published online: 11 DEC 2014 | DOI: 10.1002/mren.201400031

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      An overflow is installed in a micro-gas phase reactor, to achieve conditions which are comparable to industry. At first CFD calculations have been performed to evaluate the reactor setup and according to these results the reactor is modified. The overflow leads to an improved heat removal from the growing polymer particles. The performed overflow-polymerizations are compared with polymerizations in static conditions.

    2. Markovian Approach to Free-Radical Polymerization with Simultaneous Long-Chain Branching and Scission: Effect of Branching and Scission Kinetics

      Hidetaka Tobita

      Article first published online: 9 DEC 2014 | DOI: 10.1002/mren.201400042

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      The effect of branching and scission kinetics on the branched structure formation is investigated by using the analytic solution and the Monte Carlo simulation method. The illustrative calculations showed that the effect of different kinetics could be negligible when the final monomer conversion is smaller than about 25%, but may give significant differences at higher conversions as shown in the figure.

    3. Deterministic Modeling of Copolymer Microstructure: Composition Drift and Sequence Patterns

      Ivan Kryven and Piet D. Iedema

      Article first published online: 2 DEC 2014 | DOI: 10.1002/mren.201400047

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      The paper present a new deterministic approach allowing to study copolymer sequence distributions. The solution strategy is illustrated for styrene/acrylonitrile polymerization, highlighting the presence of different sequences, bimodalities, and a composition drift.

    4. Modeling of Polyamide 66 Solid State Polymerization: Drawing a Chemical Reaction Scheme

      Viviane Filgueiras, Stamatina N. Vouyiouka, Maria O. Konstantakopoulou, Anastasia C. Boussia, Constantine D. Papaspyrides, Enrique Luis Lima and José Carlos Pinto

      Article first published online: 13 NOV 2014 | DOI: 10.1002/mren.201400033

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      A chemical reaction scheme is proposed to describe polyamide 66 solid state polymerization using data measured under kinetic- and diffusion-controlled process conditions for reaction temperatures in the range of 160–200 °C and times up to 8 h. The obtained model can be correlated to industrial practice providing “safe” SSP conditions.

    5. On the Reaction Characteristics of Miniemulsion Polymerization with Aqueous Phase Initiation – Experiments and Modeling

      Tom G. T. Jansen, Jan Meuldijk, Peter A. Lovell and Alex M. van Herk

      Article first published online: 18 SEP 2014 | DOI: 10.1002/mren.201400025

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      Monomer redistribution, droplet disappearance, and narrowing of the particle size distribution have been observed for miniemulsion polymerizations of monomers with different water solubilities, initiated by water-soluble sodium persulfate. These phenomena are mechanistically explained using thermodynamic principles, clearly displaying that a one-to-one copy of monomer droplets into polymer particles is not an intrinsic property of miniemulsion polymerization.

  2. Special Article Series - Full Papers

    1. Thermal Behavior of Polyethylene Reactor Alloys Polymerized by Ziegler–Natta/Late Transition Metal Hybrid Catalyst

      Saeid Ahmadjo, Samaneh Dehghani, Gholam Hossein Zohuri, Gholam Reza Nejabat, Hamed Jafarian, Mostafa Ahmadi and Seyed Mohammad Mahdi Mortazavi

      Article first published online: 25 AUG 2014 | DOI: 10.1002/mren.201400024

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      Ziegler-Natta (ZN) and late transition metal (LTM) hybrid catalysts were synthesized and utilized in preparation of polyethylene (PE) reactor alloys. By changing reaction parameters, versatile thermal behavior from LTM-PE to ZN-PE could be obtained. The proposed method seems to be a promising approach for synthesis of tailor-made polyethylene in a single reactor.

  3. Full Papers

    1. Poly(Urea–Urethane) Synthesis by Miniemulsion Polymerization Using Microwaves and Conventional Polymerization

      Alexsandra Valério, Montserrat Fortuny, Alexandre F. Santos, Pedro H. H. Araújo and Claudia Sayer

      Article first published online: 18 AUG 2014 | DOI: 10.1002/mren.201400029

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      The effect of microwave irradiation during step growth polymerization in miniemulsion to form poly(urea–urethane) nanoparticles is evaluated for different reaction temperatures and polyol types, including oil soluble and water soluble polyols.

    2. High Temperature High Pressure Tandem Polymerization of Ethylene for Synthesis of Ethylene-1-Hexene Copolymers from Single Reactor with SNS-Cr and CGC-Ti Catalysts

      Song Guo, Hong Fan, Zhiyang Bu, Bo-Geng Li and Shiping Zhu

      Article first published online: 6 AUG 2014 | DOI: 10.1002/mren.201400027

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      Ethylene-1-hexene copolymers are synthesized from ethylene using the tandem catalyst system of SNS-Cr and CGC-Ti with MAO. The tandem polymerization is carried out in a high temperature high pressure solution process. Applying a short period of pre-trimerization effectively increases the 1-hexene content in copolymer and produces chains having uniform microstructure. The resulting copolymer exhibits competitive mechanical properties with a commercial ethylene-1-octene copolymer.

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