Different Forms of the Adaptogen Bacopa monnieri (Brahmi) in the Synthesis of RPU/PIR Foams

Various forms of Bacopa monnieri (BM), including original powder (Mp), tea form (Mo), and post-extraction residues (Mf), were used as natural bio-based additives in rigid polyurethane-polyisocyanurate (RPU/PIR) foams. The study investigated the influence of BM form and content on the physical, mechanical, thermal, and flammability properties of the foams. The results demonstrated that both the type and concentration of BM significantly affected foam performance. Foams containing Mf exhibited the lowest apparent density and reduced brittleness, whereas foams modified with Mp showed the highest compressive strength. The incorporation of BM also contributed to reduced flammability and enhanced thermal resistance of the foams. Thermal analysis indicated that BM additives modified the degradation behavior of RPU/PIR foams by promoting char formation and improving thermal stability at elevated temperatures. In particular, samples containing tea and post-extraction residues showed increased stability of the carbonized residue during the final degradation stage. The most favorable overall properties were obtained for BM contents between 3 and 7 wt%, while higher filler concentrations negatively affected the structural integrity of the foam matrix. The results confirm that the performance of RPU/PIR foams strongly depends on the balance between matrix continuity and biofiller functionality. The obtained materials show potential for application in floristry products and lightweight insulating systems where low density, dimensional stability, and enhanced thermal resistance are required.