Thermal Degradation Behavior of Polyethylene Grades in Presence of Phenolic and Phosphite-Based Antioxidant Additives Compound

Processing stabilizing efficiency of phenolic primary antioxidant/phosphorous secondary antioxidant stabilizer packages depends on the type, amount and ratio of the additives, as well as on the type of the polymer and the processing conditions. In this research, the effects of irgafos 168, as a phosphite secondary antioxidant, and TNPP, as currently used phosphite antioxidant, on the degradation behavior of High (HDPE), Medium (MDPE) and Linear Low Density Polyethylene (LLDPE) grades were compared and investigated. Thermal stability of samples obtained by study of changes in Yellow Index (YI) and Melt Flow Index (MFI) for all samples, determined after four times extrusion. As showed the YI results, most of samples preserved colors after four times extrusion and according to MFI results, changes in MFI results after four times extrusion were limited, so that indicates the performance of antioxidant combination for these samples are acceptable. The results shows that applying a particular and appropriate combination of phenolic/irgafos 168 antioxidant package for each of polyethyle grades was effective enough to take TNPP place in our produced samples

کلیدواژه ها:

Antioxidants ، polyethylene grades ، characterization ، Thermal stability