One-pot syntheses of heterotelechelic α-vinyl,ω-methoxysilane polyethylenes and condensation into comb-like and star-like polymers with high chain end functionality

Abstract

Crystalline and functional comb-like and star-like polyethylene architectures.

A multi-functional chromone-modified polyethylene obtained by metal-free C–H activation

“…High temperature 1 H and 13 C NMR analyses were performed on a Bruker Avance III 400 MHz spectrometer at 110 °C. The melting temperatures (T m ) of the samples were measured by differential scanning calorimetry (DSC) on a TA instruments DSC25 system using a heat-cool-heat method under nitrogen at a heating rate of 10 °C min −1 .…”

“…0.2 mol% CM grafting contents and no obvious chain coupling was observed (entries 17 and 18). The incorporation of CM into PE was characterized by 1 H NMR, 13 C NMR, and FTIR. In the 1 H NMR spectrum (Fig.…”

“…[1][2][3][4][5][6][7] Post-polymerization modification is a powerful strategy for producing polymers with different properties from the same substrate and with well-defined macromolecular architectures, especially for those inaccessible through direct polymerization. [8][9][10][11][12][13] While this concept is as old as polymer science itself, synthetic routes for macromolecular modification have advanced remarkably through adopting the developed small molecule chemistries in recent decades. However, because of the limited reactivity of fully saturated and nonpolar molecular structures, the development of practical and chemoselective approaches for introducing functional groups into polyolefins remains a challenge to date.…”

Organosilicon‐functionalized polyolefins, a kind of designable and versatile polymer: From preparation to applications

“…However, factors including β‐elimination reaction during polymerization, impurities in methoxysilanes, or incomplete deactivation reactions inevitably induced the existence of a small amount of ω‐methyl PE, which was mixed in the ω‐methoxysilane PE. [ 61 ]…”

Highly Versatile Strategy for the Production of Telechelic Polyolefins

“…Unfortunately, in contrast to well-established categories of telechelic polymers obtained through step-growth polymerization (e.g., polyesters, polyamides, and polyurethanes), the polymer science and technology of telechelic polyolefins are surprisingly still largely unexplored areas . Ideally, a general strategy for obtaining telechelic polyolefins should be able to provide control over (1) molar mass, (2) MMD, as defined by the breadth, skewness, and modality (e.g., monomodal, bimodal, or multimodal), (3) tacticity, with this parameter ranging from being stereorandom (i.e., atactic) to highly stereoregular (e.g., isotactic), (4) a broad structural scope of polymerizable olefin monomers, (5) a highly versatile range of end-group functionalities, and most importantly, (6) the ability to generate practical quantities of these telechelic polyolefin products from readily available and inexpensive reagents and standard reactor and polymerization techniques. − Indeed, finding a viable solution to the challenge of meeting all of these goals for the production of telechelic polyolefins is so difficult that, to the best of our knowledge, it has never been achieved. − Herein, we now report a general and highly versatile strategy for the production of semicrystalline telechelic α,ω-bis­(phenyl)-terminated polyethene and either amorphorus, atactic or semicrystalline, isotactic α,ω-bis­(phenyl)-terminated poly­(α-olefins) via (stereomodulated) living coordinative chain transfer polymerization (LCCTP) using a group 4 metal ion-pair initiator, and excess equivalents of diphenylzinc (ZnPh 2 ) as a chain transfer agent (CTA), followed by reactive quench with molecular iodine (I 2 ) and Cu-catalyzed phenylation according to Scheme . We further demonstrate that the phenyl group in these polyolefins can serve as a synthon for an extensive array of different functionalities that can be “unmasked” by industrially relevant, high-yielding transformations, such as the electrophilic aromatic substitution and reduction chemistry reported in the present study.…”