Pyrolysis of Heteroatom Polymers

During the pyrolysis of mixed waste plastic, one of the main problems associated with the feedstock recycling is the presence of plastic containing hetroatoms, e.g. PVC, ABS, PVDC, etc. Efforts are made to remove the heteroatoms before pyrolysis. Chlorine can be removed either by thermal degradation or by using a catalyst. The HCl generated in the process can be used as industrial hydrochloric acid. 

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Rotary Kiln Pyrolysis of Polymers Containing Heteroatoms... 

These different mechanisms and prodnct distribntions, to some extent, are related to the bond dissociation energies, the chain defects of the polymers, and the degree of aromaticity, as well as the presence of halogen and other heteroatoms in the polymer chains. Large amount of styrene monomers can be obtained by pyrolysis of PS, while a wide range of hydrocarbons are prodnced by random degradation of PE and PP [3, 59, 60]. 

High-temperatnre pyrolysis and cracking of waste thermoplastic polymers, such as polyethylene, polypropylene and polystyrene is an environmentally acceptable method of recycling. These type of processes embrace both thermal pyrolysis and cracking, catalytic cracking and hydrocracking in the presence of hydrogen. Mainly polyethylene, polypropylene and polystyrene are used as the feedstock for pyrolysis since they have no heteroatom content and the liquid products are theoretically free of sulfur. 

Pyrolysis is probably one of the oldest approaches utilized to synthesize conductive polymers by heating the polymer to form extended aromatic structures, thus eliminating heteroatoms. The product of polymer hydrolysis can be a film, a powder, or a fiber, depending on the form and nature of the standing polymer and the pyrolysis condition. 

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