Polyethylene terephthalate is a semicrystalline thermoplastic polyester built of terephthalate units alternating with ethylene glycol residues [1]. Each repeat unit carries a rigid aromatic ring and a flexible glycol segment, so the chain is stiff enough to crystallise yet mobile above the glass transition near 78 degrees Celsius [2]. Crystallinity develops between roughly 130 and 240 degrees Celsius and governs density, barrier behaviour and clarity, which is why amorphous and crystallised grades differ in the same properties [1]. Melting near 255 degrees Celsius bounds the processing window, and the ester linkage is the point at which hydrolysis and transesterification act [3]. Copolymers that replace the glycol or the diacid segment shift both transitions and are distinguished from the homopolymer [2].
- pet polyester
- semicrystalline polyester
- crystallinity
- glass transition
- ester linkage
- transesterification
Synthesis and properties of polymers·Polymers and Plastics·Materials Science·Physical Sciences
References
- Chervakov, D.O.; Varlan, K.Y.; Chervakov, O.V.; Sverdlikovska, O.S. REACTIVE EXTRUSION OF POLY(ETHYLENE TEREPHTHALATE): A REVIEW. Journal of Chemistry and Technologies 2026, 34, 237-248. [CrossRef]
- Shah, T.H.; Gamlen, G.A.; Dollimore, D.; Bhatty, J.I. Aspects of the Chemistry of Poly (Ethylene Terephthalate). IV. Hydrolysis of Poly(Ethylene Terephthalate) in the Melt Phase. Journal of Macromolecular Science: Part A - Chemistry 1985, 22, 1545-1555. [CrossRef]
- Di Lorenzo, M.L. Crystallization of Poly(ethylene terephthalate): A Review. Polymers 2024, 16, 1975. [CrossRef]