Chemical Composition Distribution and Temperature Rising Elution Fractionation of Linear Olefin Block Copolymers

Macro Reaction Engineering

Soares

2016

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low comonomer reactivity ratio and produces high-crystallinity blocks (hard-blocks), while the other catalyst has high comonomer reactivity ratio and makes low-crystallinity blocks (soft-blocks). The CSA is the special component because it shuttles living polymer chains between the two catalysts, making chains with alternating hard and soft blocks. [1][2][3][4][5][6][7] OBCs have higher heat and abrasion resistances, and better processability than conventional polyolefin elastomers. [8][9][10][11] Because OBC may have many blocks, mathematical models are needed to quantify how polymerization conditions affect their microstructures. A detailed mathematical model describes how the complex OBC microstructure evolves during polymerization, providing useful insights on how to control these microstructures. Models for chain-shuttling polymerization in continuous stirred-tank reactors (CSTRs) were first developed using the method of moments to describe polymerization kinetics and average chain microstructures. [12,13] Because this approach cannot generate detailed microstructural distributions, Monte Carlo (MC) models were later developed for OBCs made in CSTRs operated at steadystate. [14][15][16] Subsequently, Mohammadi et al. developed Chain-shuttling polymerization with dual catalysts has introduced a new class of polyolefins called olefin block copolymers (OBCs). A dynamic Monte Carlo model to describe the kinetics of chain-shuttling copolymerization in a semi-batch reactor is developed, and used it to study how the microstructure of OBCs with different numbers of blocks per chain evolves during polymerization. The model also describes how chain-shuttling rate constants and concentration of chain-shuttling agent affect populations of OBCs with different numbers of blocks per chain. These model predictions are useful to make OBCs with precisely designed microstructures.

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

Understanding the Formation of Linear Olefin Block Copolymers with Dynamic Monte Carlo Simulation

Tongtummachat

Macro Reaction Engineering

Soares

2016

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“…Several mathematical models have been developed to provide useful insights on how polymerization conditions affect the microstructure of OBCs based on the polymerization mechanism, kinetic parameters, and reaction conditions reported by Zhang et al…”

Section: Introductionmentioning

confidence: 99%

“…Steady‐state Monte Carlo (MC) models were developed later to predict these distributions for OBCs made in CSTRs . Unfortunately, this approach cannot describe dynamic responses, such as those happening in CSTRs during grade transitions and/or nonsteady‐state operation nor in semi‐batch polymerizations.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Monte Carlo Simulation of Olefin Block Copolymers (OBCs) Produced via Chain‐Shuttling Polymerization: Effect of Kinetic Rate Constants on Chain Microstructure

Tongtummachat

Macro Reaction Engineering

Soares

2018

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The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/mren.201800021. PolyolefinsOlefin block copolymers (OBCs) are thermoplastic elastomers with unique statistical multiblock structures produced by chain-shuttling polymerization. In this study, a dynamic Monte Carlo model is used to simulate the effect of changing chain-shuttling (k CS ), catalyst deactivation (k d ), and chain transfer (k tr ) rate constants on the microstructure of OBCs made in a semi-batch reactor. The simulations show how each rate constant governs different aspects of the OBC chains and provide guidelines on how to fine-tune OBC microstructure to achieve precisely designed multiblock structures.

“…Monte Carlo models were later developed to estimate these microstructural distributions. Anantawaraskul et al developed a Monte Carlo model to predict the distribution of number of blocks, CCD, and LESD for OBCs made in a continuous stirred tank reactor operated at steady state . The effects of polymerization parameters on these distributions were also reported.…”

Section: Introductionmentioning

confidence: 99%

Monte Carlo Simulation of Olefin Block Copolymers: Bivariate Distribution of Molecular Weight and Chemical Composition

Buakrong

Macromolecular Symposia

Soares³

2018

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The multi-block structure of olefin block copolymers (OBCs) leads to their unique properties, in contrast to those of traditional polyolefin elastomers. In this work, the detailed bivariate distribution of molecular weight and chemical composition (MWD Â CCD) of OBCs is examined using Monte Carlo simulation. The effects of polymerization parameters on the bivariate MWD Â CCD are also studied and reported for the first time. This model can be used as a tool to describe how to produce OBCs with desired microstructures by manipulating the polymerization conditions.