Robust Self-Healing Adhesives Based on Dynamic Urethane Exchange Reactions.

Thermoset polyurethanes (PUs) have been successfully reprocessed as covalent adaptable networks (CANs) by catalyzing carbamate exchange. Here we extend bond exchange beyond the internal network cross-links to create a dynamic urethane adhesive. Interfacing PU CANs to substrates with nucleophilic functional groups creates adhesives capable of reversible transcarbamoylation with the substrate, which has not been demonstrated previously by CAN adhesives.

Perfluoroalkyl acid adsorption by styrenic β-cyclodextrin polymers, anion-exchange resins, and activated carbon is inhibited by matrix constituents in different ways.

Perfluoroalkyl acids (PFAAs) are ubiquitous environmental contaminants of global concern, and adsorption processes are the most widely used technologies to remove PFAAs from water. However, there remains little data on the ways that specific water matrix constituents inhibit the adsorption of PFAAs on different adsorbents. In this study, we evaluated the adsorption of 13 PFAAs on two styrene-functionalized β-cyclodextrin (StyDex) polymers, an activated carbon (AC), and an anion-exchange resin (AER) in the absence and presence of specific water matrix constituents (16 unique water matrices) in batch experiments.

Low-Temperature Mineralization of Fluorotelomers with Diverse Polar Head Groups.

Per- and polyfluoroalkyl substances (PFAS) are persistent environmental pollutants linked to harmful health effects. Currently employed PFAS destruction methods are energy-intensive and often produce shorter-chain and recalcitrant partially fluorinated byproducts. We report the mineralization of five fluorotelomer compounds via a base-mediated degradation using NaOH and mild temperatures (120 °C) in a mixture of DMSO:HO (8:1 v/v).

Nonclassical Crystallization Processes of Single-Crystalline Two-Dimensional Covalent Organic Frameworks.

Controlling the two-dimensional polymerization processes of two-dimensional covalent organic frameworks (2D COFs) is essential to fully realizing their distinct properties. Although most 2D COFs have been isolated as polycrystalline aggregates with only nanometer-scale crystalline domains, we have identified rapid, solvothermal conditions that provide micrometer-scale and larger single-crystal 2D polymers for a few 2D COFs. Yet it remains unclear why certain conditions produce far larger 2D polymers than others, which hinders generalizing these findings.