HYDROLYSIS OF PET AND ITS USE IN CEMENT

Abstract

Polyethylene terephthalate, commonly abbreviated PET, PETE, PETP/PET-P, is the most common thermoplastic polymer resin of the polyester family and is used in fibres for clothing, containers for liquids and foods, thermoforming for manufacturing, and in combination with glass fibre for engineering resins. The majority of the world's PET production is for synthetic fibers (> 60%), with bottle production accounting for about 30% of global demand. In the context of textile applications, PET is referred as polyester, whereas the acronym PET is generally used in relation to packaging. Polyester makes up about 18% of world polymer production and is the fourth-most-produced polymer after polyethylene (PE), polypropylene (PP) and polyvinyl chloride (PVC), respectively.PET consists of polymerized units of the monomer ethylene terephthalate, with repeating (C10H8O4) unit. PET is commonly recycled, and has the number 1 as its recycling symbol. Depending on its processing and thermal history, polyethylene terephthalate may exist both as an amorphous (transparent) and as a semi-crystalline polymer. The semi-crystalline material might appear transparent (particle size < 500 nm) or opaque and white (particle size up to a few micrometres) depending on its crystal structure and particle size. Its monomer bis(2-hydroxyethyl) terephthalate can be synthesized by the esterification reaction between terephthalic acid and ethylene glycol with water as a by-product, or by transesterification reaction between ethylene glycol and dimethyl terephthalate with methanol as a by-product. Polymerization is carried out through a polycondensation reaction of the monomers (immediately after esterification/ transesterification) with water as the by-product, polyethylene terephthalate, a strong, stiff synthetic fibre and resin, and a member of the polyester family of polymers.