Thermal decomposition of p-tert-butyl-calix[n]arene was studied using thermo gravimetry (TG) and differential thermo gram (DTG) methods. Non-isothermal TG was done under static air atmosphere with 1, 2.5, 5.0 and 10.0 K/min. Model-free methods such as Friedman and Flynn Wall Ozawa (FWO) were used to evaluate the kinetic parameters such as activation energy and exponential factors. The probable thermal decomposition mechanism was proposed by analyzing the quenched intermediate p-tert-butyl-calix[n]arene samples with FTIR, mass, H-1 NMR, C-13 NMR cross polarization magic angle spectrometry (CP-MAS), EPR spectroscopy and elemental analysis. The thermal stability of the polyolefins was checked with p-tert-butyl-calix[n]arene as an antioxidant additive. (C) 2013 Elsevier B.V. All rights reserved.