Thermal Analysis and Decomposition Temperatures of HPOPs

Thermogravimetric analysis (TGA) or differential scanning calorimetry (DSC) can be used to determine decomposition temperatures and activation energies (E ) of materials. TGA was used to determine the decomposition temperature and activation energy for decomposition organic pigments. 

If the plot of the log of the heating rate versus 1/T is linear, then the energy of activation can be calculated from the slope of the Hne according to the Arrhenius equation. 

This is illustrated in the case of C.I. PR254. Table 21.6 shows the temperature at which 2.5%, 5.0%, and 100.0% decomposition of C.I. PR254 has oocurred. 

The results show that the HPOPs have higher decomposition temperatures and better thermal stability than the classical pigments such as C.L PR49 1 or C.l. PY 74. Also increasing the chlorination level of C.L PB15 1 from 0 to 4 increases the thermal stability. 

Pigment manufacturers must comply with numerous environmental requirements including heavy metals, polychlorinated biphenyls (PCBs), polychlorinated dibenzo dioxins (PCDD), polychlorinated dibenzofurans (PCDFs), hejachoroben-zene, regulations for self-heating pigments, specific state or local county regulations, and customer specific requirements. 

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