The effect of salt and oxide-hydroxide additives on the pyrolysis of cellulose and Pinus halepensis pine needles

Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA) were used to study the effects of various salts and oxide-hydroxide additives on the pyrolysis of cellulose and Pinus halepensis pine needles. (NH4)(2)HPO4, NaH2PO4, (NH4)(2)SO4, NaHCO3, KHCO3, (COONa)(2), Ca(OH)(2) and Na2O.CaO were used as additives at concentrations of 4% w/w and 10% w/w. DSC and TGA showed that the addition of (NH4)(2)HPO4, NaH2PO4 and (NH4)(2)SO4 on cellulose causes a significant shift to lower pyrolysis temperatures, i.e. 50 degrees C to 80 degrees C, as well as a significant increase in char residues. The effect of NaHCO3, KHCO3, and (COONa)(2) on the pyrolysis of cellulose was also found to be significant in terms of the DSC profile, while the increase in char residues was moderate. In contrast the effect of Ca(OH)(2) and Na2O . CaO on the pyrolysis of cellulose was found to be minor, under the above-mentioned criteria. The above chemicals, tested as fire retardants, have shown minor effects on the pyrolysis of Pinus halepensis pine needles. Some changes, however, were noticed in the solid pyrolysis residues, particularly when (NH4)(2)HPO4 and (NH4)(2)SO4 were used.