Identification of blowing agents in cellular PVC compounds by DSC Part 2. The detection and identification of azodicarbonamide

The determination by DSC of azodicarbonamide concentrations in PVC cellular powder formulations revealed a linear relationship between concentration and the decomposition enthalpy of the compound. Both the detection limits and the sensitivity of the method are reported. Furthermore, it has been shown that the enthalpy of azodicarbonamide decomposition is affected by cellular PVC compound formulation. This effect has produced an artificially high detection limit and lowered the sensitivity of the method in respect of the detection of azodicarbonamide in the polymer blend. As a result, the quantitative DSC method described herein is limited to azodicarbonamide concentrations above 0.5 wt.% in cellular PVC formulations.