Green and Facile Preparation of Readily Dual-Recyclable Thermosetting Polymers with Superior Stability Based on Asymmetric Acetal

Abstract

Recycling thermosets have become extremely important due to their ecological and economic benefits. The development of thermosets that undergo reversible polymerization provides a solution to the end-life disposal issue of thermosetting materials. However, the synthesis and recycling of the current chemically recyclable thermosets are harsh, complex, and energyintensive, and their stability is often low. Here, we designed asymmetric acetal-containing thermosets (PRCs) from general phenolic resin and 1,4-cyclohexanedimethanol divinyl ether through one-step "click" cross-linking without using catalysts and solvents and without releasing small-molecule byproducts. PRCs exhibited conspicuous stress relaxation via a dissociative mechanism, corresponding to the superior malleability and reprocess recyclability. Importantly, PRCs presented excellent creep resistance even at 100 °C. In addition, PRCs could be readily and highly efficiently recovered to original phenolic resin via hydrolysis under specific mild acidic conditions but possessed high chemical stability under neutral conditions and even weak acidic conditions or acidic conditions in the absence of organic solvents with outstanding wettability and swellability toward the samples. Thermosets with different properties could be easily achieved via regulating raw materials. This work provides a promising dynamic covalent motif and a practical method to produce readily dual-recyclable (reprocess recyclable and chemically recyclable) thermosets with superior performance and stability.

Abrasion and Fracture Self‐Healable Triboelectric Nanogenerator with Ultrahigh Stretchability and Long‐Term Durability

“…To demonstrate it, the activation energy of bond exchange reaction has been calculated. [34] The τ * obeyed the Arrhenius equation (Equation 1) with the temperature for all samples.…”

Stimuli‐responsive mechanical properties in polymer glasses: challenges and opportunities for defense applications

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High Heat-Resistant and Degradable Polybenzoxazines with a Diacetal Structure

“…In recent years, many methods have been put forward to solve this problem. The introduction of some unstable bonds or links to the skeleton structure of the thermosetting resins is a preferred method to endow them with degradability. ,− For example, some special structures can make the thermosetting resins degraded under mild conditions, such as esters, acetal structure, sulfur-containing linkages, Schiff base, and so on. ,,− However, these degradable thermosetting resins are weak in heat resistance, which limits their practical application. In some high-tech fields, the thermosetting resins with high heat resistance are required.…”