Quantitative thermogravimetric-mass spectrometric analysis for monitoring the effects of fire retardants on cellulose pyrolysis Original Research Article

The effects of two fire retardant materials, (NH4)2SO4 and (NH4)2HPO4, on cellulose pyrolysis studied using thermogravimetry-mass spectrometry (TG-MS) analysis. In order to determine quantitatively H2O and CO2 during pure and fire retarded cellulose pyrolysis, the MS signal was calibrated using KHCO3 decomposition. The MS signal calibration in relation to the flow stability through TG-MS interface was examined. The influence of the TG furnace temperature on MS signal, and the effects of heat and mass transfer phenomena were also discussed. Furthermore, the criteria for evaluating the effectiveness of the fire retardant compounds on cellulose pyrolysis were examined. Both fire retardant compounds resulted in the increase of the non-combustible pyrolysis products, such as H2O and CO2, and char. Low levels of levoglucosan were recorded. It appears that in the presence of the fire retardant compounds a relative increase of levoglucosenone in the evolved gases is observed. Finally, the effects of the fire retardants on the pyrolysis mechanism were discussed.