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ABSTRACT The introduction of degradable units into the backbone of commodity vinyl polymers represents a major opportunity to address the societal challenge of plastic waste and polymer recycling. Previously, we reported the facile copolymerization ofα‐lipoic acid derivatives containing 1,2‐dithiolane rings with vinyl monomers leading to the incorporation of degradable S–S disulfide bonds along the backbone at relatively high dithiolane monomer feed ratios. To further enhance the recyclability of these systems, here we describe a facile and user‐friendly strategy for backbone degradation at significantly lower dithiolane loading levels through cleavage of both SS and SC backbone units. Copolymers ofn‐butyl acrylate (nBA) or styrene (St) with small amounts of eitherα‐lipoic acid (LA) or ethyl lipoate (ELp) dissolved in DMF were observed to undergo efficient degradation when heated at 100°C under air. For example, at only 5 mol% ELp, a high molecular weight poly(ELp‐co‐nBA) (M_n = 62 kg mol⁻¹) degraded to low molecular weight oligomers (M_n = 3.2 kg mol⁻¹) by simple heating in DMF. In contrast, extended heating of either poly(nBA) or poly(St) homopolymers under the same conditions did not lead to any change in molecular weight or cleavage of the C–C backbone. This novel approach allows for the effective degradation of vinyl‐based polymers with negligible impact on properties and performance due to the low levels of dithiolane incorporation. 

Abstract Shear‐recoverable hydrogels based on block copolypeptides with rapid self‐recovery hold potential in extrudable and injectable 3D‐printing applications. In this work, a series of 3‐arm star‐shaped block copolypeptides composed of an inner hydrophilic poly(l‐glutamate) domain and an outer β‐sheet forming domain is synthesized with varying side chains and block lengths. By changing the β‐sheet forming domains, hydrogels with diverse microstructures and mechanical properties are prepared and structure–function relationships are determined using scattering and rheological techniques. Differences in the properties of these materials are amplified during direct‐ink writing with a strong correlation observed between printability and material chemistry. Significantly, it is observed that non‐canonical β‐sheet blocks based on phenyl glycine form more stable networks with superior mechanical properties and writability compared to widely used natural amino acid counterparts. The versatile design available through block copolypeptide materials provides a robust platform to access tunable material properties based solely on molecular design. These systems can be exploited in extrusion‐based applications such as 3D‐printing without the need for additives.