Thermal stabilization mechanisms of a waste acrylic fabric containing methylacrylate(MA) only as the comonomer were studied using differential scanning calorimetry (DSC) and subsequent Fourier transform infrared spectroscopy (FTIR). It has been found first that the thermal stabilization behavior of the waste fabric containging MA depends on the heating rate and environmental atmospheric condition : atmosphere and the slow heating rate(e.g. 2 $^{circ}C$/min) produce double exotherms whereas the nitrogen atmosphere and fast heating rate(e.g. 1$0^{circ}C$/min) result In a single exotherm. The different thermal behavior is explained with the newly established stabilization mechanisms which are extracted from the computer analysis of the FTIR spectral changes based on the curve fitting and curve-resolution techniques.