A Comparative Study of the Reinforcing Effect of Bauxite Residue in Pentaerythritol and Expandable Graphite Based Intumescent Systems

Abstract:

Intumescent systems are passive fire-retardant systems which employ the insulative property of a condensed char. The texture, strength and appearance of the intumescent char are affected by the individual fire-retardant components. In the present work, the char behaviors of chemically reactive and physically reactive intumescent systems were compared. Bauxite residue (BR) was used as reinforcing filler in pentaerythritol (PER)/ammonium phosphate (APP), a chemically reactive system, and expandable graphite (EG)/ammonium phosphate (APP), a physically reactive intumescent system. BR was found to have antagonistic effect on the char properties of the traditional PER-APP system due to chemical interference with the intumescent reaction. Secondly, the resulting highly viscous char impeded the expansion of available intumescent gases. Consequently, a hard, crusty, char was produced with the degree of expansion reducing from 18.5 to 1.2. On the other hand, the graphite flakes expanded independent of the intumescent reaction, their forceful expansion complimented the BR-reinforced viscous char resulting in a stronger, compact, expanded char. Therefore, EG-intumescent systems may be said to be less selective in its synergism compared to PER-intumescent systems. BR offers a promising potential as a cohesive, reinforcing filler for EG-based intumescent systems.

• Periodical: Advanced Materials Research (Volume 1184)
• Pages: 3-12
• DOI: https://doi.org/10.4028/p-EX8eLa
• Online since: November 2025
• Authors: Adiat Ibironke Arogundade*, Puteri Sri Melor Megat Yussof, Faiz Ahmad, Ibrahim Dauda Muhammad
• Keywords: Bauxite Residue, Char Reinforcement, Expandable Graphite, Intumescence, Pentaerythritol

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