Nylon 66, Nylon 46 and PET Phase Transfer Catalyzed Alkaline Depolymerization at Atmospheric Pressure

Abstract

Plastic waste recycling is beneficial because it can lead to a reduction in the amount of waste generated, a decreased need for landfills, and a more rational utilization of resources. An important source of polyethylene terephthalate (PET) for recycling is physically cleaned post-consumer bottles which are ground to form flake, depolymerized, purified, and repolymerized to form recycled resin bottles. Caustic treatment of polyester scrap involves cleavage of the ester linkages. The reaction of aqueous sodium hydroxide (8–10% by weight) with waste material in an autoclave at 210–250°C and elevated pressure goes to completion in about 3–5 hours¹. The rate of hydrolysis may be enhanced by the presence of accelerants^2,3. Terephthalic acid and ethylene glycol may be recovered from the solution. Hall³ used cetyl trimethylammonium bromide and lauryl dimethylbenzylammonium chloride as accelerants for the caustic reduction of PET.