Synthesis and characterization of polyolefin thermoplastic elastomers: A review

Abstract

Polyolefin thermoplastic elastomers (TPE‐Os) are high‐performance polyolefins consisting of both plastic and rubber phases. Compared with other thermoplastic elastomers, the TPE‐Os possess better chemical stability, transparency, re‐processability, and electrical insulation, which renders their broad applications possible. By manipulating chain structures and topologies of the TPE‐Os, differently structured polyolefins with improved thermal and mechanical properties have been developed, including ethylene and α‐olefin random copolymers (POEs), olefin block copolymers (OBCs), comb‐shaped polyolefin elastomers (CPOEs), and dynamically cross‐linked polyolefin elastomers. Herein, we review the synthesis of the POE, OBC, CPOE, and dynamical cross‐linked polyolefin elastomer, including the catalyst systems, polymerization techniques, processes, and kinetic modelling. The characterization of the TPE‐Os and the relationships between the TPE‐O chain structure, aggregated state, and product performance are discussed. The future development of higher‐performance TPE‐Os is envisaged.

Archie E. Hamielec memorial issue

“…The authors of the articles in this issue join us from many countries and institutions across the globe (Figure 1 and Table 1) to thank Archie for his enduring legacy in polymerization reaction engineering, a field of academic and industrial interest that he established practically single‐handedly. [ 1–45 ]…”

Bimodal and Highly Branched Polyethylenes Using Dual-Site Nickel Catalysts Supported on an Unsymmetrical BIAN-PI Compartmental Ligand Scaffold

“…In terms of the structural properties of the multinuclear catalyst, the type/number of metal centers, the M···M proximity, the nature of the linking group together with the properties of the local N,N -nickel coordination environment can all affect the catalytic performance of a multinuclear catalyst. , The latter point can be exemplified by symmetrical binuclear nickel complexes such as F (Chart ), ,− which on account of the similarity of the local coordination environments, tend to produce only saturated polyethylenes with narrow dispersity, thereby limiting the understanding of the mode of cooperation in the polymerization process. Moreover, such monodisperse polymers can present difficulties in industrial-scale processing as well as postfunctionalization chemistry …”

“…Moreover, such monodisperse polymers can present difficulties in industrial-scale processing 42 as well as postfunctionalization chemistry. 43 With the aim to produce bimodal polyethylenes containing a higher molecular weight component (for mechanical toughness) and lower molecular weight one (to allow processability) in one pot, we report the results of a program directed toward synthesizing unsymmetrical bimetallic nickel polymerization catalysts. In particular, a series of dinickel complexes of type G (Chart 1) is targeted, that contain well-separated metal centers that are located within distinct coordination environments within a compartmental ligand.…”

High-Performance Olefin Thermoplastic Elastomer Based on Dynamically Cross-Linking Crystalline Macromers and Elastic Backbones

“…5 Recently, CPOEs with an amorphous soft backbone and multiple crystallizable hard grafting chains have been developed; 1,6−8 the two segments can be facilely regulated in polymerization to have high and adjustable T m s of 121−144 °C, σ of up to 11.0 MPa, ε of up to 1400%. 5 Generally, engineering the physical crystallization in TPE-Os can improve their mechanical performance and heat resistance and enable processability. However, from the point of view of intermolecular force, physical crystallization is a type of van der Waals interaction with relatively weak binding energy (<10 kJ• mol −1 ), which limits the further performance improvement of TPE-Os.…”

“…Whereafter, the OBC with a multiblock structure of alternating hard and soft segments was developed; , it has a more ordered crystallization structure with a higher T m of up to ∼120 °C, tensile stress at break (σ) of up to 15.0 MPa, and elongation at break (ε) of up to 1300% . Recently, CPOEs with an amorphous soft backbone and multiple crystallizable hard grafting chains have been developed; ,− the two segments can be facilely regulated in polymerization to have high and adjustable T m s of 121–144 °C, σ of up to 11.0 MPa, ε of up to 1400% . Generally, engineering the physical crystallization in TPE-Os can improve their mechanical performance and heat resistance and enable processability.…”