Thermal analysis of a sodium salt of the maleic acid-acrylic acid copolymer used as a polymeric binder RAPID COMMUNICATION

摘要

Samples of sodium salt of the maleic acid-acrylic acid copolymer used as a binding agent in molding sands were investigated. Methods of thermal analysis (DTG, TG, DSC) were applied to assess the thermal stability of the investigated polymer sample by estimation of temperature and thermal effects of transformations occurring during its heating. Examinations were performed at the temperature range -100—1000 °C. It was found that the total degradation process starts at the temperature about 400 °C. In addition, the analysis of volatile decomposition products was carried out by means of the Fourier transform infrared spectroscopy (FT-IR) and the thermogravimetric (TG) method coupled "on-line" with the mass spectrometry (MS) method. At the temperature range 300—400 °C the signals for small molecular masses were found, which indicates that the degradation process and the fragmentation of polymer chains occurred as well as small particles were formed (molecular weight: 15—55), including, first of all, H2O and CO2. Probably during the degradation radicals are also formed, which is indicated by the MS signals.