Issue 19, 2024

Phytic acid derivatized lignin as a thermally stable and flame retardant material

Abstract

Phosphorus-containing flame retardants have attracted attention due to their outstanding flame retardancy, enhanced thermal stability, and limited toxic smoke emission. Bio-based phosphorus-containing flame retardants could be excellent options to impart environmental benefits, renewability, and sustainability to these materials. Lignin is an underutilized but abundant and sustainable material that can be used to serve this purpose. In the present work, a lignin-derived flame retardant was produced following the facile solvent-free polycondensation reaction of kraft lignin (KL) and phytic acid (PHA) at a low temperature in an aqueous system. The optimized conditions for this reaction were 1/0.4 mol/mol KL/PHA, pH 11, 20 °C, and 20 min. By utilizing advanced NMR (H, P, and HSQC), XPS, and FTIR techniques, the covalent bonding of the phosphorus of PHA with the oxygen of aliphatic and aromatic hydroxyl groups of KL was confirmed. C–P–O and P–O–P bonds provided high decomposition temperature (Tmax), high glass transition temperature (Tg), and char formation in the product. The presence of phosphorus atoms was observed on the combusted material by EDS mapping and EDX, illustrating the increase in the intensity of this element after combustion at 800 °C. The results of this work provided a new approach for preparing a fully bio-based flame-retardant with limited smoke density (i.e., a decrease from 34% for KL to 17.7% for modified KL) and a higher limiting oxygen index (i.e., an increase from 21.8% for KL to 26% for modified KL) following a green chemistry concept.

Graphical abstract: Phytic acid derivatized lignin as a thermally stable and flame retardant material

Supplementary files

Article information

Article type
Paper
Submitted
30 Jun 2024
Accepted
17 Jul 2024
First published
29 Jul 2024

Green Chem., 2024,26, 10070-10086

Phytic acid derivatized lignin as a thermally stable and flame retardant material

S. Khodavandegar and P. Fatehi, Green Chem., 2024, 26, 10070 DOI: 10.1039/D4GC03169E

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements