Toward Safer and Greener Insulation: Formaldehyde-Free, Flame-Retardant, and Bio-Based Phenolic Foams from Tannin and Modified-Lignin Combination
Abstract
This study reports on the use of degraded lignin in combination with tannins to develop sustainable, formaldehyde-free, and bio-based phenolic foams. Mechanical, thermal, and flame-retardant properties of the different foams were systematically evaluated using compression testing, thermogravimetric analysis (TGA), mass loss cone calorimetry (MLC), and UL-94 flammability tests. Lignin degradation/activation was carried out via a hydrothermal process in the presence of ethanol. Ethanol-induced lignin hydrogenolysis and thermal degradation were deemed a necessary step to obtain foams with satisfactory mechanical, morphological, and thermal insulation properties. Meanwhile, the fire resistance assessed by MLC remains comparable to that of tannin-based foams, with a similarly low peak heat release rate (pHRR).
Fields of Study & Subjects
Flame retardant materials and properties
Lignin and Wood Chemistry
Polymer composites and self-healing
Publication details
- Journal / source
- Materials
- Publisher
- MDPI AG
- Volume
- 19
- Issue
- 2
- Pages
- 334–334
- Publication date
- 14 January 2026
- Language
- EN