Solution-processable and functionalizable ultra-high molecular weight polymers via topochemical synthesis

Topochemical polymerization reactions hold the promise of producing ultra-high molecular weight crystalline polymers. However, the totality of topochemical polymerization reactions has failed to produce ultra-high molecular weight polymers that are both soluble and display variable functionality, which are restrained by the crystal-packing and reactivity requirements on their respective monomers in the solid state. Herein, we demonstrate the topochemical polymerization reaction of a family of para-azaquinodimethane compounds that undergo facile visible light and thermally initiated polymerization in the solid state, allowing for the first determination of a topochemical polymer crystal structure resolved via the cryoelectron microscopy technique of microcrystal electron diffraction. The topochemical polymerization reaction also displays excellent functional group tolerance, accommodating both solubilizing side chains and reactive groups that allow for post-polymerization functionalization. The thus-produced soluble ultra-high molecular weight polymers display superior capacitive energy storage properties. This study overcomes several synthetic and characterization challenges amongst topochemical polymerization reactions, representing a critical step toward their broader application.

Quantification of branching within high molecular weight polymers with polyester backbones formed by transfer-dominated branching radical telomerisation (TBRT)

The characterisation and quantification of branching is key to understanding new complex macromolecules. Here we establish approaches to evaluate the unique and novel architectures formed by Transfer-dominated Branching Radical Telomerisation (TBRT).

An unsymmetrical binuclear iminopyridine-iron complex and its catalytic isoprene polymerization

A series of chloride-bridged unsymmetrical Fe(ii)-HS/Fe(ii)-LS binuclear complexes has been developed, which can efficiently catalyze isoprene polymerization with 0.00025 mol% loading, delivering ultra-high molecular weight polymers.

Plastics: Environmental and Biotechnological Perspectives on Microbial Degradation

ABSTRACT Plastics are widely used in the global economy, and each year, at least 350 to 400 million tons are being produced. Due to poor recycling and low circular use, millions of tons accumulate annually in terrestrial or marine environments. Today it has become clear that plastic causes adverse effects in all ecosystems and that microplastics are of particular concern to our health. Therefore, recent microbial research has addressed the question of if and to what extent microorganisms can degrade plastics in the environment. This review summarizes current knowledge on microbial plastic degradation. Enzymes available act mainly on the high-molecular-weight polymers of polyethylene terephthalate (PET) and ester-based polyurethane (PUR). Unfortunately, the best PUR- and PET-active enzymes and microorganisms known still have moderate turnover rates. While many reports describing microbial communities degrading chemical additives have been published, no enzymes acting on the high-molecular-weight polymers polystyrene, polyamide, polyvinylchloride, polypropylene, ether-based polyurethane, and polyethylene are known. Together, these polymers comprise more than 80% of annual plastic production. Thus, further research is needed to significantly increase the diversity of enzymes and microorganisms acting on these polymers. This can be achieved by tapping into the global metagenomes of noncultivated microorganisms and dark matter proteins. Only then can novel biocatalysts and organisms be delivered that allow rapid degradation, recycling, or value-added use of the vast majority of most human-made polymers.

Synthesis of Ultrahigh Molecular Weight Polymers with Low PDIs by Polymerizations of 1-Decene, 1-Dodecene, and 1-Tetradecene by Cp*TiMe2(O-2,6-iPr2C6H3)–Borate Catalyst

Polymerizations of 1-decene (DC), 1-dodecene (DD), and 1-tetradecene (TD) by Cp*TiMe2(O-2,6-iPr2C6H3) (1)–[Ph3C][B(C6F5)4] (borate) catalyst have been explored in the presence of Al cocatalyst. The polymerizations of DC and DD, in n-hexane containing a mixture of AliBu3 and Al(n-C8H17)3, proceeded with high catalytic activities in a quasi-living manner, affording high molecular weight polymers (activity 4120–5860 kg-poly(DC)/mol-Ti·h, Mn for poly(DC) = 7.04–7.82 × 105, after 20 min at −30 °C). The PDI (Mw/Mn) values in the resultant polymers decreased upon increasing the ratio of Al(n-C8H17)3/AliBu3 with decreasing the activities at −30 °C. The PDI values also became low when these polymerizations were conducted at low temperatures (−40 or −50 °C); high molecular weight poly(DD) with low PDI (Mn = 5.26 × 105, Mw/Mn = 1.16) was obtained at −50 °C. The TD polymerization using 1–borate–AliBu3 catalyst (conducted in n-hexane at −30 °C) afforded ultrahigh molecular weight poly(TD) (Mn = 1.02 × 106, Mw/Mn = 1.38), and the PDI values also decreased with increasing the Al(n-C8H17)3/AliBu3 ratio.