DSC CHARACTERIZATION OF UREA FORMALDEHYDE CONDENSATES .2. EXPERIENCESWITH HIGH-PRESSURE DSC CELL/

At anisothermic thermograms registered when curing the urea/formaldehy de (UF) resins in high pressure DSC cell the endothermic effects, such as evaporation of water and elimination of formaldehyde shift to temp eratures higher by about 40 degrees C in comparison to the thermograms received using the cell without pressure. The temperature for the exo therma of curing remains unchanged. Due to the shift of decomposition temperature the elimination of formaldehyde takes place at more agreea ble conditions: as the resin is more rigid the risk of additional endo thermic effect connected with bubble blowing is diminished. The shift of water elimination temperature however disturbs at clear recognition of the base line of the endotherma. Preliminary treating of samples w ith inert gas before the measurements helps to improve the measurement conditions.