THERMAL-DEGRADATION OF POLYURETHANES BASE D ON MDI - CHARACTERISTIC RELATIONSHIPS BETWEEN THE DECOMPOSITION PARAMETERS

For a series of Diphenylmethane-4-4'-diisocyanate (MDI) and different polyols based polyurethanes (PU), oxygen index experiments (OI) and th ermogravimetric analysis (TGA) were carried out. Linear correlations b etween some thermal parameters, e.g. initial decomposition temperature (IDT), mass loss at 500 degrees C and DTG-Max-Temperature and oxygen index (or oxygen concentration), were found. The most commonly used co rrelations for evaluation of the char residue were examined and a new coefficient is proposed. In a characteristic temperature range a pyrol ysis was conducted; some volatile gas products were analysed.