writer：Qiong Li, Songqi Ma*, Sheng Wang, Yanlin Liu, Muhammad Abu Taher, Binbo Wang, Kaifeng Huang,
keywords：thermosets，recycle，asymmetric acetal，creep resistance，dynamic bonds
source：期刊
specific source：Macromolecules
Issue time：2020年

Recycling thermosets has become extremely important due to its 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 energy-intensive, and their stability is often low. Here, we designed asymmetric acetal-containing thermosets (PRCs) from general phenolic resin (PR) and 1,4-cyclohexanedimethanol divinyl ether (CDVE) through one-step “click” cross-linking without using catalyst and solvent and without releasing small-molecule by-product. 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 even weak acid 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.

论文链接：https://pubs.acs.org/doi/10.1021/acs.macromol.9b02386