Thermoplastic Polymer from Lignin: Creating an Extended Polyamide Network through Reactive Kraft Lignin Derivatives

James Sternberg; Srikanth Pilla

doi:10.1021/acsomega.3c01259

Thermoplastic Polymer from Lignin: Creating an Extended Polyamide Network through Reactive Kraft Lignin Derivatives

ACS Omega. 2023 Oct 16;8(43):40110-40118. doi: 10.1021/acsomega.3c01259. eCollection 2023 Oct 31.

Authors

James Sternberg¹, Srikanth Pilla^{2

3

4

5}

Affiliations

¹ Department of Food, Nutrition and Packaging Science, Clemson University, Clemson, South Carolina 29634, United States.
² Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, United States.
³ Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, United States.
⁴ Department of Mechanical Engineering, University of Delaware, Newark, Delaware 19716, United States.
⁵ Center for Composite Materials, University of Delaware, Newark, Delaware 19716, United States.

Abstract

Thermoplastic polymers have many desirable properties for consumer applications and are complemented by efficient thermal processing techniques, reducing the cost of manufacturing. Lignin exists as an immense biobased carbon source but has largely been researched for its use in thermoset materials due to its own cross-linked, polyfunctional nature. In this study, a new reaction design is employed to create a thermoplastic polyamide network incorporating lignin that is tested to be 99% biobased carbon by radiocarbon analysis. Chemical analysis reveals the nature of lignin incorporation based on chain extension and cross-linking models. The thermal and rheological properties of the new polymers are thoroughly investigated to demonstrate the higher melt-strength capability of the lignin-based polymers facilitating their use in modern processing equipment. This analysis results in finding an optimal lignin loading ratio in the polymer composition reflected by improved tensile strength and stiffness. The results point to a promising polymer design for applying industrial kraft lignin in high-value thermoplastic polymer applications.