Hexagonal and Orthorhombic Crystal Formations in Ethylene Glycol-Based Long-Spaced Aliphatic Polyesters Driven by Layer Packing of Proximate Ester Groups

Macromolecules, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 12, 2025

Language: Английский

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High Carbon Recovery in Photocatalytic Degradation of High-Density Polyethylene (HDPE): Blend with Stearic Acid as a Radical Source

ACS Macro Letters, Journal Year: 2025, Volume and Issue: unknown, P. 231 - 234

Published: Feb. 10, 2025

A blend of high-density polyethylene (HDPE, Mw = 59.4 kDa) and stearic acid was efficiently degraded under cerium catalyzed photodecarboxylation conditions, the molecular weight decreased to ∼5 kDa. The reaction proceeds at 100 °C in tert-butylnitrile (tBuCN) air, where HDPE does not dissolve or swell. products are solid material with >90% recovery starting + acid. Control experiments supported that carbon radicals generated by cerium-catalyzed transferred main chain HDPE, which undergoes oxidative degradation lower weight.

Language: Английский

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Modular Access from Acrylate to a Sustainable Polyester Platform with Large-Span Tunability and Chemical Circularity under Mild Conditions

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: March 4, 2025

Making polyesters with conventional vinyl monomers is one of the most economical ways to develop sustainable polymeric materials. For polar vinyls, while their transformation into lactones has been studied extensively, there exists no further access synthesizing polyesters, presumably due nonstrained and nonpolymerizable nature obtained lactones. Herein, we report first facile synthesis that originated from critical classes vinyls-acrylates. Specifically, a series modular six-membered were rationally designed synthesized methyl acrylate together malonic esters containing diverse functional groups formaldehyde. The underwent ring-opening polymerization (ROP) yield acrylate-derived which constitute unique polymer platform large scope potential functionalities performances as well easy chemical circularity under mild conditions. Notably, are rare example featuring tunable on side ester whose impact certain material properties (e.g., glass transition temperature) similar polyacrylates, implying replacement between polyacrylates. In addition, by presenting special geminal disubstitutions originally monomers' γ-position for time, also exhibited unprecedentedly enhanced thermal recycling properties: Variation offers large-span modulation completely amorphous high-level crystalline materials, melting temperature high crystallinity was drastically increased 84 °C compared reported monosubstituted counterpart. At same other required harsh conditions (>150 vacuum), gem-disubstituted in this work can undergo complete much milder (80 ambient pressure). This study informs design future high-performance derived vinyls.

Language: Английский

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Selective carboxylation of alkenes with CO2 to form unsaturated carboxylic acid on Sc-exchanged MFI zeolite

Catalysis Today, Journal Year: 2025, Volume and Issue: unknown, P. 115321 - 115321

Published: April 1, 2025

Language: Английский

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