Visualized Degradation of Poly(alkynoate)s Toward Diols and Structure Controlled Multifunctional N-Heterocyclic Compounds

Degradable polymers are highly desirable due to the tremendous growth of polymer wastes. Some polymers could be degraded under strong acidic or basic conditions toward unknown or unvalued products (i.e. downcycling). New methods to degrade polymers into monomers or high-value-added materials (i.e. upcycling) are more preferred for sustainable developments. In this work, linear and cross-linked poly(alkynoate)s were successfully degraded by benzamidine with 100% conversion into not only diols, a kind of monomers, but also high-value-added N-heterocyclic compounds of pyrimidone and imidazolone derivatives in high yields through controlling the reaction conditions. Notably, thanks to the AIE feature of the degraded products, the degradation process could be visualized under UV light via gradually increased luminescent intensity of the reaction mixtures, which facilitates the monitoring of the polymer degradation. Using this highly efficient degradation reaction, fluorescence patterns could be generated through microcontact printing (μCP) of the stamp on the thin films of poly(alkynoate)s. Moreover, the pyrimidone derivatives could be applied in bioimaging and inhibiting bacteria, and the imidazolone derivatives could be used for the detection and recovery of gold (III) ions from electronic waste and serve as the fluorescent sensor to detect in situ generated amines from food spoilage. Thus, this work presents a visualized and high value product-selective degradation to solve the end-of-life issue of polymers.