Synthesis and Characterization of Aliphatic-Aromatic Copolyesters From Pet Waste and ϵ-Caprolactone

Abstract

Copolyesters containing aliphatic units in the main chain were obtained by reacting Bis(2-hydroxy ethyl terephthalate) (BHET) with ϵ-caprolactone (ϵ-CL) at a high temperature in bulk in the presence of tin octoate as catalyst. Various copolyesters were synthesized by using BHET/ϵ-CL mass ratio ranging from 90/10 to 10/90. Thermal properties were studied by DSC and TGA, and structural characterization was carried out by ¹H-NMR spectroscopy. These techniques confirm the insertion of lactones units in PET chains. The degree of randomness of 30/70 to 60/40 copolyesters, determined by ¹H-NMR, shows a random microstructure. The other copolyesters exhibit some block copolymer character.

Keywords:

• Copolymerization
• melt polycondensation
• bis(2-hydroxy ethyl terephthalate)
• ϵ-caprolactone
• random microstructure