Thiol‐Aldehyde Polycondensation for Bio‐based Adaptable and Degradable Phenolic Polymers

Abstract

Designing sustainable materials with tunable mechanical properties, intrinsic degradability, and recyclability from renewable biomass through a mild process has become vital in polymer science. Traditional phenolic resins are generally considered to be not degradable or recyclable. Here we report the design and synthesis of linear and network structured phenolic polymers using facile polycondensation between natural aldehyde‐bearing phenolic compounds and polymercaptans. Linear phenolic products are amorphous with Tg between −9 °C and 12 °C. Cross‐linked networks from vanillin and its di‐aldehyde derivative exhibited excellent mechanical strength between 6–64 MPa. The connecting dithioacetals are associatively adaptable strong bonds and susceptible to degradation in oxidative conditions to regenerate vanillin. These results highlight the potential of biobased sustainable phenolic polymers with recyclability and selective degradation, as a complement to the traditional phenol‐formaldehyde resins.

A straightforward and rapid synthesis of polydithioacetals in the presence of chlorodimethylsilane

“…Notably, the M n s of PDTA P6 and P8 were comparable to those obtained from the recent work of Xu and Yuan. 40 However, they prepared these phenolic PDTAs from corresponding aldehydes and dithiols within 30 min catalyzed by CF 3 COOH in MeOH at room temperature. Different functionalities were also introduced into the PDTA backbone as part of the aldehyde library.…”

“…In the meantime, Xu and Yuan synthesized PDTAs from aldehyde functionalized bio-based phenols and dithiols (or polymercaptans) under trifluoroacetic acid (CF 3 COOH) or ZrCl 4 catalysis in methanol (MeOH) or tetrahydrofuran (THF) at room temperature for 30 min. 40 The produced phenolic polymers showed vitrimer-like properties, and the associative dynamic exchange was found to promote reprocessing. The reactions of disulfide and thioester dynamic sulfur-based bonds employed in dynamic covalent chemistry were comprehensively reviewed by Orillo and Furlan.…”