Biobased Precursors for One-Pot Upgradable Multi Dynamic Linkages Based Covalent Adaptable Networks With Tunable Mechanical Behaviour.

Covalent adaptable networks (CANs) are potentially considered as a viable alternative to one-time use plastics and their stimuli responsiveness render them suitable for application in a range of functional domains. However, most of the CANs reported in literature are based on a single dynamic linkage. In this report, we explore a biobased functional motif for synthesis of thioacetal based CANs, which may be suitably functionalized to serve as a precursor for CANs with multiple dynamic linkages such as thioacetal, thia-Michael adduct and Diels Alder adduct. This opens the window for tailoring mechanical and responsive behavior of the resulting CANs. As a proof of concept, 5-hydroxymethylfurfural is utilized for the synthesis of thioacetal based CANs (PEMP-HMF-n) in presence of a tetra-thiol crosslinker and its acrylate functionalized derivative is exploited for multi dynamic linkage-based CAN (PEMP-HMFA-n) in presence of the above crosslinker. The resulting PEMP-HMFA-n films display five-time increase in tensile stress value compared to that of the PEMP-HMF-n supporting the design philosophy.