Synthesis, structural study and hydrolytic degradation of copolymer based on glycolic acid and bis-2-hydroxyethyl terephthalate

• Published in: Polymer degradation and stability 2009-02, Vol.94 (2), p.221-226
• Main Authors: Olewnik, E., Czerwiński, W.
• Format: Article
• Language: English
• Subjects: Ageing; Applied sciences; Copolymerization; Exact sciences and technology; Glycolic acid; Hydrolysis; Physical properties; Poly(ethylene terephthalate); Polymer industry, paints, wood; Properties and testing; Technology of polymers
• ISSN: 0141-3910; 1873-2321
• DOI: 10.1016/j.polymdegradstab.2008.10.026

The current demand for environmentally degradable copolymers has initiated the use of novel degradable copolyesters. One of them is a copolyester based on poly(ethylene terephthalate- co-glycolic acid) (PET–GLA). The copolymer was synthesized by the melt reaction of bis-2-hydroxyethyl terephthalate (BHET) with glycolic acid (GLA) oligomers in the presence of Sb 2O 3 as a catalyst. Hydrolytic degradation of the copolymer was carried out in two buffered solutions at 45 °C: degradation was studied by incubating samples in powder form, in a concentrated solution from 30 to 150 days. The copolymer before and after degradation was characterized by means of different analytical techniques. 1H and 13C NMR spectroscopy was used to confirm the incorporation of glycolide units in PET chains and to observe the structure and decomposition of the novel polyester. The thermal properties and morphology before and during the degradation were studied by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermogravimetric (TG) analysis for determining melting points as well as melting and decomposition temperatures of investigated copolyester.