Fly-Ash based Flame-Retardant Cellulose Materials for Strengthening and Value-Added Utilization in Industrial Solid Wastes

Abstract

Cellulose, a bio-based material, is increasingly researched and valued for its abundant availability and exceptional characteristics. However, Cellulose has a flammable problem. This study addresses this issue by integrating it with industrial waste fly ash (FA) to overcome its natural flammability. By solution compounding, the study successfully developed cellulose/FA films and porous structures, significantly boosting the material's flame-retardant capabilities. This innovation not only enhances the practical application of cellulose but also promotes the high-value reuse of FA, resonating with the principles of sustainable development. The cellulose/FA hydrogel, characterized by a homogeneous and stable blend of FA particles and cellulose, achieves this through effective affinity and hydrogen bonding, ensuring optimal miscibility and encapsulation. In terms of thermal properties, the modified composites (C-F10, C-F20 and C-F30) demonstrate a substantial increase in initial decomposition temperatures, approximately 26℃ higher than pure cellulose, ranging between 282℃ and 302℃. This enhancement is attributed to the formation of an inorganic protective layer on the cellulose matrix, which significantly improves thermal stability while maintaining key mechanical properties. Remarkably, the flame retardancy of these materials shows notable improvement, particularly at a 30wt% FA concentration, with the limiting oxygen index (LOI) of the porous and film structures reaching around 29% and 31%, respectively. This advancement greatly elevates their flame resistance. Overall, this study presents a pioneering approach in developing eco-friendly, flame-retardant materials by repurposing industrial waste, marking a significant stride in sustainable material innovation.