The overall schematic diagram of the apparatus used in this study is shown in Fig. 1. The experiment was carried out in a Pyrex glass reactor (volume 75 cm3) under atmospheric pressure at an isothermal temperature of either 350, 400, 450, or 500 °C. Nitrogen gas was continuously passed at a flow rate of 30 cc/min to purge the remain­ing air in the reactor to ensure inert atmosphere. In a typical run, 10 g of HDPE sam­ple and 5-10 % by weight of catalyst were blended together before being fed into the reactor. The reactor was heated to 120 °C in 60 min and held for 60 min at 120 °C. The nitrogen flow was then cut off, and the temperature was increased from 120 °C at a heating rate of 30 °C/min up to the desired temperature. The temperature of the polymer was measured with a thermocouple (Type J). The outlet of the reactor was connected to a water-cooling condenser maintaining at 20-25 °C. The gases (Cl-C5) were separated from the liquid oils (C5-C25) and then analyzed using a gas chromato­graph. The products from the reactor were collected over a period of 3-4 h.