Towards Olefin Multi-block Copolymers with Tailored Properties: A Molecular Perspective

This is an Accepted Manuscript of an article published by Macromolecular Theory and Simulations (MTS), of Wiley. Mohammadi, Y., Saeb, M. R., Penlidis, A., Jabbari, E., Stadler, F. J., Zinck, P., & Vivaldo‐Lima, E. (2021). Toward olefin multiblock copolymers with tailored properties: A molecular perspective. Macromolecular Theory and Simulations, 30(3), 2100003. https://doi.org/10.1002/mats.202100003Recent progress in macromolecular reaction engineering has enabled the synthesis of sequence-controlled polymers. The advent of Olefin Block Copolymers (OBCs) via chain shuttling polymerization of ethylene with α-olefins has opened new horizons for the synthesis of polyolefins having a dual character of thermoplastics and elastomers. Nevertheless, the use of two catalysts with different comonomer selectivities and a chain shuttling agent, dragging and dropping live chains between active catalyst centers, made precise tailoring of OBCs microstructure containing hard and soft units a feasible challenge. This work discusses the possibility of predicting properties of OBCs from its simulated molecular patterns. The microstructural characteristics of OBCs are discussed in terms of topology-related and property-related features. An intelligent tool, which combines the benefits of Kinetic Monte Carlo simulation and Artificial Neural Network modeling, was used to explore the connection between polymerization recipe (catalyst composition, ethylene to 1-octene monomer ratio, and chain shuttling agent level) and topology-related as well as property-related microstructural features. The properties of target OBCs are reflected in the hard block percent, the number of 1-octene units in the copolymer chains, and the longest ethylene sequence length of the hard and soft segments

Modeling of the Copolymerization Kinetics of n-Butyl Acrylate and d-Limonene Using PREDICI ®

Kinetic modeling of the bulk copolymerization of d-limonene (Lim) and n-butyl acrylate (BA) at 80 °C was performed using PREDICI®. Model predictions of conversion, copolymer composition and average molecular weights are compared to experimental data at five different feed compositions (BA mol fraction = 0.5 to 0.9). The model illustrates the significant effects of degradative chain transfer due to the allylic structure of Lim as well as the intramolecular chain transfer mechanism due to BA

Special Issue: Modeling and Simulation of Polymerization Processes

This Special Issue (SI) of Processes on Modeling and Simulation of Polymerization Processes (MSPP), and the associated Special Issue reprint, contain papers that deal with this very important area of scientific investigation in polymer science and engineering, both in academic and particularly industrial environments [...

Modeling of RAFT copolymerization with crosslinking of styrene/divinylbenzene in supercritical Carbon Dioxide

A kinetic model for the reversible addition-fragmentation chain transfer radical copolymerization of vinyl/divinyl monomers in supercritical carbon dioxide, using a multifunctional approach for polymer network formation, is presented. The process is assumed to proceed as a dispersion polymerization in three stages, with two phases: CO2- and polymer-rich phases. A simple model for partition of the main components within the two phases is used. Experimental data of monomer conversion, molar mass development, evolution of gel fraction, and swelling of the polymer network for a styrene/divinylbenzene system, at 80 °C and 300 bar, are used to validate the model. Good agreement between model predictions and experimental data is obtained

Thermosetting Polymers

International audienceThermosetting polymers (also called thermosets) are a family of plastics characterized by the fact that they are formed starting from a liquid solution that irreversibly leads to a solid material during a heating step. This chapter focuses on some aspects of the chemistry of epoxy polymers because it provides examples of both step-growth and chain-growth polymerizations employed in the synthesis of polymer networks. The chapter explains structural transformations such as gelation, vitrification, that take place during network formation. Then, it talks about rules for processing thermosetting polymers. Processing techniques for thermosetting polymers are described in what follows in relation to the most extended applications

Modeling of the Free Radical Copolymerization Kinetics of n-Butyl Acrylate, Methyl Methacrylate and 2-Ethylhexyl Acrylate Using PREDICI®

Kinetic modeling of the bulk free radical copolymerizations of n-butyl acrylate (BA) and 2-ethylhexyl acrylate (EHA); methyl methacrylate (MMA) and EHA; as well as BA, MMA and EHA was performed using the software PREDICI®. Predicted results of conversion versus time, composition versus conversion, and molecular weight development are compared against experimental data at different feed compositions. Diffusion-controlled effects and backbiting for BA were incorporated into the model as they proved to be significant in these polymerizations. The set of estimated global parameters allows one to assess the performance of these copolymerization systems over a wide range of monomer compositions

Modeling the electrical behaviour of conducting elastomers based on inherent conducting polymers

Printed electronics is a branch of technology dedicated to create devices and gadgets which are able to be portable, flexible, folded if necessary and in consequence very light. These devices will require energy sources with the same characteristics of the device (portable, light and able to be folded). For that reason we have worked on elastomeric conducting materials able to be used as capacitors in galvanic cells or rechargeable batteries 1. These elastomeric composites are the resulting blend from three polymers: SBS or SBR elastomers as matrix; An inherent conducting polymer nano-composite based on poly(3,4-ethylenedioxythiophene) synthetized over halloysite nanotubes or PEDOT:HT; And a extrinsic ionic conducting polymer based on acrylics dispersed with lithium salts in the proper solvent to obtain a kind of elastomeric acrylic. These components are not miscible between themselves, but they were blended in a mixing chamber to disperse the electrically conducting phases in the elastomeric matrix, so we obtain an elastomeric composite able to be processed by extrusion or rolling milling to obtain flexible films. The present job discusses about how these electrically conducting phases were obtained and characterized, but mainly about the distribution of these conducting phases inside the matrix, by employing a scanning electronic microscopy (SEM) and a DualBeam Versa 3D microscopy. An integrated methodology that enabled linking 3D spatial orientation and bulk structure, enables to estimate the volume fraction occupied by the elastomeric matric (SBS or SBR), figure 1. Moreover, we used this information to generate an idealized theoretical distribution of materials, figure 2, as an input, in a Hashin-Shtrikman model 2, to simulate the electrically conductive behavior of the elastomeric composite and compared it with electrical conductivity measures done using a Keithley electrometer at different voltages