Recent developments in entropy‐driven ring‐opening metathesis polymerization: Mechanistic considerations, unique functionality, and sequence control

Abstract

Entropy‐driven ROMP (ED‐ROMP) involves polymerization of olefin‐containing macrocyclic monomers under entropically favorable conditions. Macrocycles can be prepared from a variety of interesting molecules which, when polymerized, impart unique functionality to the resulting polymer backbone such as degradable linkages, biological moieties, crystallizable groups, or supramolecular hosts. In addition, the sequence of atoms in the cyclic monomer is preserved within the polymer repeating units, allowing for facile preparation of sequence‐defined polymers. In this review article, we consider how the mechanism of ROMP applies to ED polymerizations, how olefinic macrocycles are synthesized, and how polymerization conditions can be tuned to maximize conversion. Recent works in the past 10 years are highlighted, with emphasis on methods which can be employed to achieve fast polymerization kinetics and/or selective head‐to‐tail regiochemistry, thus improving polymerization control. ED‐ROMP, with its unique capability to produce polymers with well‐defined polymer backbone microstructure, represents an essential complement to other, well‐established, metathesis methodologies such as ROMP. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1621–1634

Oxanorbornenes: promising new single addition monomers for the metathesis polymerization

“…14 Over the past few years, ROMP has been used to synthesize sequence dened polymers, mostly alternating copolymers. [15][16][17][18][19][20][21]66 Several approaches have been made to achieve alternating ring-opening metathesis polymerization (AROMP) either via catalyst modication or through monomer design. [22][23][24][25][26][27][28][29][30] In 2009, Sampson and co-workers reported an AROMP strategy where cyclobutene-1-carboxylic esters undergo ring-opening metathesis with a ruthenium catalyst giving an enoic carbene incapable of homopropagation.…”

ED-ROP of macrocyclic oligomers: A synthetic tool for multicomponent polymer materials

“…This technique allows for the preparation of polymers with unique backbone functionality, with prethreaded supramolecular guest molecules, and with well-defined sequences. 51,52 ED-ROMP of macrocyclic olefins containing the deoxycholic acid moiety to give functionalized polymers and copolymers was reported by Hodge and Chakiri. 61 Three new families of macrocyclic olefins were prepared from deoxycholic acid.…”

“…Therefore, cyclic oligomers can be usefully added in minor amounts to intentionally lower the polymer melt viscosity during its processing without however affecting the final material properties, since, by raising the temperature, MCOs undergo spontaneous ring opening (the source of end groups being the admixed linear polymer chains) to give exactly the same macromolecules constituting the parent polymer. 49 Over the past dozen years, ED-ROP and related topics have been discussed in several review works, some of them being of a general purpose, 14,25 others focusing on the various polymerization techniques, 50 such as the "cousin" entropically-driven ring-opening metathesis polymerization (ED-ROMP) process, 51,52 others on applications of the resulting materials, 51,53,54 reactivity of the most developed cyclic oligomers, i.e., cyclic butylene terephthalate, 26,53,55 combination of CDP plus ED-ROP for polymer recycling, 56 and ring opening of macrocyclic oligo esters obtained from renewable resources. 27 In this review, the effectiveness of ED-ROP of MCOs as an efficient and versatile synthetic tool either to achieve multicomponent polymer materials (copolymers, blends, composites and nanocomposites) or facilitate their processing, compatibilization, properties modification or recycling is demonstrated through selected, representative examples, mostly taken from recent literature.…”

Scalable synthesis and polymerisation of a β-angelica lactone derived monomer

“…The ring-opening metathesis polymerisation (ROMP) of the DA adducts was next investigated. [68][69][70] Grubbs' 2 nd generation catalyst was chosen for this (Fig. 1).…”