Polyurethane foams (PUF) are prepared by polycondensation of isocyanates with polyols (diols, triols, polyethers, or polyesters) followed by the internal generation or liberation of a gas in a fluid medium that simultaneously polymerizes while expanding in volume.1 The modification of PUF with some organic reagents is a very promising approach employed in the adsorption. The addition of specific reagents to PU foam can increases the efficiency of adsorption. 2,3 In this study, a new type of flexible polyurethane foam containing p-tert-butyl thiacalix[4]arene (TC4A) macrocycle was synthesized. TC4A macrocycle was incorporated into polyurethane foam as a part of crosslinking agent as well as glycerol. Structural, morphological, thermal and mechanical properties of TC4A based polyurethane foam (TC-PUF) were studied and compared with conventional polyurethane foam based on glycerol as crosslinking agent (PUF). SEM images showed that the both PUF and TC-PUF foams possess roughly open cell structures with a non-uniform cell size distribution. The TGA results indicated that with incorporation of TC4A, the thermal stability of polyurethane foam was improved. Furthermore, the addition of TC4A as a part of crosslinking agent leads to an increase in the LogE′ (the logarithm of storage modulus) value. This increasing in storage modulus for TC-PUF compared to PUF can be attributed to the increase of crosslink density and reduction in chain movement with addition of TC4A macrocycle containing four OH groups. The new TC4A imbedded open-cell polyurethane foam was used as a high performance adsorbent for removal of malachite green from aqueous media using batch adsorption technique. Thus, the adsorption of malachite green from aqueous solutions was studied by prepared polyurethane foams. The effects of different parameters such as the dose of the adsorption, the initial pH, the temperature and the contact time were studied. The equilibrium adsorption data were modeled using the Lang
