Chemical Recycling of Poly(ethylene terephthalate)

Abstract

This paper covers the recent research carried out by the authors on the chemical recycling of poly(ethylene terephthalate) (PET) taken from post‐consumer soft‐drink bottles. The chemical recycling techniques used are critically reviewed and the authors' contribution is highlighted. Hydrolysis in either an alkaline or acid environment was employed in order to recover pure terephthalic acid monomer that could be repolymerized to form the polymer again. Alkaline hydrolysis was carried out in either an aqueous NaOH solution or in a non‐aqueous solution of KOH in methyl cellosolve. A phase‐transfer catalyst was introduced in alkaline hydrolysis, in order that the reaction takes place at atmospheric pressure and in mild experimental conditions. The reaction kinetics were thoroughly investigated, both experimentally and theoretically, using a simple, yet precise, kinetic model. Moreover, glycolysis was examined as an effective way for the production of secondary value‐added materials. The glycolysated PET products (oligomers) can be used as raw materials for the production of either unsaturated polyester resins (UPR) or methacrylated oligoesters (MO). UPR can subsequently be cured with styrene in ambient temperature to produce alkyd resins used as enamel paints or coatings. MO are potential monomers that can be cured either by UV irradiation or temperature to produce formulations used as coatings for wood surfaces, paints, or other applications. Thus, recycling of PET does not only serve as a partial solution to the solid‐waste problem, but also contributes to the conservation of raw petrochemical products and energy.magnified image

Toughness of ABS/PBT blends: The relationship between composition, morphology, and fracture behavior

“…It is well known that the morphology studies are often hindered by lack of contrast between different phases. Inspired by chemical recycling of polyester, in which the strong basic solution is utilized to hydrolyze the polyester chain . We have etched PBT phase of ABS/PBT/ASG blends by hot KOH solution.…”

Toughness of ABS/PBT blends: The relationship between composition, morphology, and fracture behavior

“…It is well known that the morphology studies are often hindered by lack of contrast between different phases. Inspired by chemical recycling of polyester, in which the strong basic solution is utilized to hydrolyze the polyester chain . We have etched PBT phase of ABS/PBT/ASG blends by hot KOH solution.…”

Non-Calcium Inorganic Materials Fabrication by Surface-Immobilized Organic Molecular Template

“…Not like inert BOPP, PET is a relatively reactive substrate containing abundant ester bonds, which are capable to undergo hydrolysis reactions in aqueous environments (Karayannidis et al, 2007). Similar to our consideration, Pizem et al (Pizem et al, 2005) also pointed out that during the solution deposition process of a titanium film on polyimide substrates, reactive imide groups could be partially hydrolyzed and thereby influence the acidic oxide deposition solution.…”

Synthesis of two PET waste derived bisacrylic and bisallylic monomers and their potential use as crosslinking agents and dental resin composites

“…In this work, we observed a slightly higher yield, 89% after 2 h of depolimerization, using double EG and catalyst concentrations, for irregular PET particles ranging from 1 to 2.8 mm. It has been reported that for PET hydrolysis in alkaline conditions, the smaller the particle size the higher the rate and the degree of PET degradation, because smaller particles have increased surface area available for the reaction . We observed faster conversions, about 45 min for smaller particle sizes, ranging from 0.1 to 1 mm.…”

Toughness of ABS/PBT blends: The relationship between composition, morphology, and fracture behavior

“…It is well known that the morphology studies are often hindered by lack of contrast between different phases. Inspired by chemical recycling of polyester, in which the strong basic solution is utilized to hydrolyze the polyester chain . We have etched PBT phase of ABS/PBT/ASG blends by hot KOH solution.…”

Non-Calcium Inorganic Materials Fabrication by Surface-Immobilized Organic Molecular Template

“…Not like inert BOPP, PET is a relatively reactive substrate containing abundant ester bonds, which are capable to undergo hydrolysis reactions in aqueous environments (Karayannidis et al, 2007). Similar to our consideration, Pizem et al (Pizem et al, 2005) also pointed out that during the solution deposition process of a titanium film on polyimide substrates, reactive imide groups could be partially hydrolyzed and thereby influence the acidic oxide deposition solution.…”

Synthesis of two PET waste derived bisacrylic and bisallylic monomers and their potential use as crosslinking agents and dental resin composites

“…In this work, we observed a slightly higher yield, 89% after 2 h of depolimerization, using double EG and catalyst concentrations, for irregular PET particles ranging from 1 to 2.8 mm. It has been reported that for PET hydrolysis in alkaline conditions, the smaller the particle size the higher the rate and the degree of PET degradation, because smaller particles have increased surface area available for the reaction . We observed faster conversions, about 45 min for smaller particle sizes, ranging from 0.1 to 1 mm.…”

Toughness of ABS/PBT blends: The relationship between composition, morphology, and fracture behavior

“…It is well known that the morphology studies are often hindered by lack of contrast between different phases. Inspired by chemical recycling of polyester, in which the strong basic solution is utilized to hydrolyze the polyester chain . We have etched PBT phase of ABS/PBT/ASG blends by hot KOH solution.…”

Non-Calcium Inorganic Materials Fabrication by Surface-Immobilized Organic Molecular Template

“…Not like inert BOPP, PET is a relatively reactive substrate containing abundant ester bonds, which are capable to undergo hydrolysis reactions in aqueous environments (Karayannidis et al, 2007). Similar to our consideration, Pizem et al (Pizem et al, 2005) also pointed out that during the solution deposition process of a titanium film on polyimide substrates, reactive imide groups could be partially hydrolyzed and thereby influence the acidic oxide deposition solution.…”

Synthesis of two PET waste derived bisacrylic and bisallylic monomers and their potential use as crosslinking agents and dental resin composites

“…In this work, we observed a slightly higher yield, 89% after 2 h of depolimerization, using double EG and catalyst concentrations, for irregular PET particles ranging from 1 to 2.8 mm. It has been reported that for PET hydrolysis in alkaline conditions, the smaller the particle size the higher the rate and the degree of PET degradation, because smaller particles have increased surface area available for the reaction . We observed faster conversions, about 45 min for smaller particle sizes, ranging from 0.1 to 1 mm.…”