A study of parameters interfering in oxidative induction time (OIT) results obtained by differential scanning calorimetry in polyolefin (original) (raw)

Sample preparation and test conditions are parameters recognised to influence Oxidative Induction Time (OIT) results obtained by Differential Scanning Calorimetry (DSC). Therefore, many laboratory practices have been written to prevent this interference. However, quantitative results on the variability of OIT as a function of these parameters have not been presented systematically in the literature. The following parameters were investigated using a two level factorial design and High Density Polyethylene samples: (1) sample shape-pulverising and cutting pieces of sample; (2) amount of sample-2 and 8 mg; (3) heating rates to reach the isotherm-fast and 10°C/min; (4) oxygen flow-20 and 60 ml/min. Sample shape, amount of sample and heating rate were the parameters that showed significant variability. Higher order interactions were considered negligible. Finally, the variation of the parameters under assessment was described by a linear model obtained with the aide of the chemometric method of Yates' Algorithm.