Effect of Residual Catalyst Levels on Polyethylene Degradation Behavior

In this paper, four linear low density polyethylenes were subjected to multiple extrusion processes for 20 times. Then Yellowness Index (YI) were evaluated as a function of the number of extrusion cycles. Using the X-ray fluorescence (XRF), the residual catalyst levels were determined in these samples. The highest YI value was observed for samples LL-518N. Also, the lowest YI value was obtained for sample LL-209. The YI value for the sample LL-209 has been approximately constant after 3 times the extrusion. Furthermore, the XRF results showed that Residual Catalyst (aluminium, magnesium and titanium) Level in samples LL-518N was more than LL-209. Therefore, it can be concluded that high residual catalyst level is one of the reasons for the high value of the Yellowness Index