Thermal reactions of polyethylene with coal (TG/DSC approach)

Thermal reactions of polyethylene with coal were studied. Coal used exhibited an endothermal effect in the temperature range of 425-495°C with a flat maximum (about 460°C). In contrast, polyethylene alone was decomposed in the temperature range of 420-540°C (mainly of 485-540°C) with the significant DSC maximum at 510°C. In the presence of coal this maximum shifted to lower temperature (483°C), therefore, coal promoted the decomposition of polyethylene. As decomposition of polyethylene yields alkenes and alkadienes, the thermal reaction of polyethylene with coal under low temperature conditions can be described as two-stage process in which the first stage includes the decomposition of polyethylene giving unsaturated hydrocarbons and the second stage adsorption and hydrogenation of these products (mainly by coal hydrogen) on the inner surfaces of semicoke and coal.