Tuneable N‐Substituted Polyamides with High Biomass Content via Ugi 4 Component Polymerization

• Published in: Macromolecular chemistry and physics 2022-07, Vol.223 (13), p.n/a
• Main Authors: MacKinnon, Daniel, Zhao, Tieshuai, Becer, C. Remzi
• Format: Article
• Language: English
• Subjects: Aldehydes; Biomass; Contact angle; Diamines; Glass transition temperature; Hydrophobicity; multi component reactions; Polyamide resins; polyamides; Polymers; Reaction time; Substitutes; sustainable polymers; Thermal stability; Ugi 4‐component reactions; vanillin; Water purification
• ISSN: 1022-1352; 1521-3935
• DOI: 10.1002/macp.202100408

Ugi 4‐component reaction (Ugi 4CR) is an efficient tool which benefits from high atom efficiency, compatibility with green solvents such as methanol, simple purification, and a water side‐product. By using two bifunctional starting materials for Ugi 4CR, N‐substituted polyamides can be prepared via a step‐growth process. As polyamides play important roles in applications including films, and adhesives, the preparation of N‐substituted functional polyamides from largely sustainable monomers is investigated. Herein, the combination of renewable diamine, diacid, and aldehydes with commercially available isocyanides yield polyamides with tuneable side chain functionalities and ≈80% biomass content. Relatively high yields (up to 96%) are recorded for polymers of moderate molecular weights (Mw up to 8100 g mol−1). The prepared polyamides possess backbones which exhibit excellent thermal stability (Tdeg = 440 ± 10 °C), while functional side chains result in additional lower‐temperature degradations (215–285 °C). Side‐group variation enables shifting of the glass transition temperature (Tg) between 9 and 38 °C and causes variation in hydrophobicity resulting in water contact angles ranging from 47 o to 105 o. This work presents a reliable approach to prepare sustainable polymers with diverse side chain functionalities in a short reaction time and without need for catalysts or complicated purifications. N‐Substituted polyamides with high biomass content and tunable physical properties, such as glass transition temperature and hydrophobicity, are prepared via an efficient catalyst‐free Ugi 4‐component reaction polymerization in an optimized solvent system. The obtained polyamides, which show excellent thermal stability and near‐room temperature glass transitions, highlight the potential of the Ugi reaction in the synthesis of tunable polyamides from biomass.