An investigation of the smoke suppression and the thermal degradation in the smouldering mode of poly (vinyl chloride) containing a combination of cuprous oxide and molybdenum trioxide

The smoke suppression and the thermal degradation of poly (vinyl chloride) treated with Cu2O, MoO3 and the combination of Cu2O and MoO3 (Cu2O/MoO3) were investigated using thermogravimetry and cone calorimetry in the smouldering mode under an incident heat flux of 25 kW m(-2). Even though MoO3 increased total smoke production (TSP) of PVC, Cu2O/MoO3 still showed synergism in reducing smoke emission. Cu2O, MoO3 and Cu2O/MoO3 effectively reduced smoke emission during HCl-elimination. These results demonstrated that these transition metal oxides promoted crosslinking of PVC, and stabilized the carbon backbone. MoO3 made the peak band of HCl-elimination process wider. This result is attributed to the re-addition reaction of HCl and polyene catalyzed by MoO2Cl2. TGA data indicated that Cu2O/MoO3 showed the synergism in increasing char residue. Cone calorimetric results are in good agreement with TGA results obtained in this work. (C) 2001 Elsevier Science Ltd. All rights reserved.