Thermal Degradation of Phenol-formaldehyde resin extended with Thiolignin (1) : Thermogravimetric analyis (TGA) and Differential thermal analysis (DTA) of the cured resin

The thermal degradation course of phenol-formaldehyde resin extended with thiolignin was investigated in air at atmospheric pressure by means of thermoanalytical methods. The sample resins were prepared with the conditions that ratio of thiolignin to phenol was 1.0 in weight and ratio of formaldehyde to phenol was 2.0 in mol., then, were cured by heating at 140℃. The DTA curves of the cured phenol-formaldehyde resins extended with thiolignin showed two peaks of exothermal reactions at lower temperatures than 550℃. The first exothermal peak (310～340℃) was attributed to thermoxidation of thiolignin, and the second (510～540℃) was done mainly to thermooxidation of phenol-formaldehyde resin. The temperature at first exothermal peak was as follows (ref. Table 1); PF: L>PF-L>PLF>LF-P The weight loss of the resins by thermal degradation was less than 50% below 550℃