Computational Insights into the Thermal Stability and Degradation Pathways of Poly(butylene adipate-co-terephthalate)

Year 2026, Volume: 22 Issue: 1, 113 - 120, 30.03.2026

Sıla Gümüştaş , Kardelen Şener , Armağan Kınal

https://doi.org/10.18466/cbayarfbe.1673557

https://izlik.org/JA42MJ68YM

Abstract

The thermal decomposition pathways, bond dissociation free energies, and product distributions of biodegradable poly(butylene adipate-co-terephthalate) (PBAT) copolymer under inert atmosphere have been investigated using density functional theory (DFT). Calculations at the B3LYP/6-311++G(d,p) level identified the most stable molecular geometries, and decomposition processes were thoroughly analyzed. Based on vibrational frequency analyses and bond dissociation energy calculations, three primary decomposition pathways (ptw1, ptw2, and ptw3) were characterized, and their Gibbs free energy changes were computed. The results indicated that pathway ptw1 (61.41 kcal/mol) has the lowest energy barrier and is the most thermodynamically favorable route for decomposition. Additionally, low molecular weight aliphatic compounds, CO₂, adipate, and terephthalate derivatives were determined as the primary decomposition products. These findings provide significant insights into the thermal stability of PBAT and the environmental impacts of its decomposition products, contributing to the development of sustainable polymer applications.

Keywords

Degradation products , DFT , Poly(butylene adipate-co-terephthalate) , Thermal degradation mechanism

Supporting Institution

TÜBİTAK

Project Number

2209A

Thanks

This work was supported by the TUBITAK (Program for the University Students at undergraduate level Program Number TUBITAK 2209-A). The DFT calculations reported in this study were performed at TÜBİTAK ULAKBİM, High Performance and Grid Computing Center (TRUBA resources).

References

• [1]. Ye, H, Li, Q, Li, J, Li, D, Ao, Z. 2025. Review on the abiotic degradation of biodegradable plastic poly(butylene adipate-terephthalate): Mechanisms and main factors of the degradation. Chinese Chemical Letters; 36(1): 109861. https://doi.org/10.1016/j.cclet.2024.109861
• [2]. Tilsted, JP, Bauer, F, Birkbeck, CD, Skovgaard, J, Rootzén, J. 2023. Ending fossil-based growth: Confronting the political economy of petrochemical plastics. One Eart; 6(6): 607-619. https://doi.org/10.1016/j.oneear.2023.05.018
• [3]. Singh, N, Ogunseitan, OA, Wong, MH, Tang, Y. 2022. Sustainable materials alternative to petrochemical plastics pollution: A review analysis. Sustainable Horizons; 2: 100016. https://doi.org/10.1016/j.horiz.2022.100016
• [4]. Tan, L-c, Qu, J-p. 2019. Characterization of poly(butylene succinate)/poly(lactic acid) blends with in-situ sub-micron fibers and intercalation structure manufacturing by volumetric pulsating elongation flow. Polymer testing; 77: 105889. https://doi.org/10.1016/j.polymertesting.2019.05.005
• [5]. Fojt, J, David, J, Přikryl, R, Řezáčová, V, Kučerík, JA. 2020. A critical review of the overlooked challenge of determining micro-bioplastics in soil. Science of The Total Environment; 745: 140975. https://doi.org/10.1016/j.scitotenv.2020.140975
• [6]. Burrows, SD, Ribeiro, F, O’Brien, S, Okoffo, E, Toapanta, T, Charlton, N, Kaserzon, S, Lin, C-Y, Tang, C, Rauert, C, Wang, X, Shimko, K, O’Brien, J, Townsend, PA, Grayson, MN, Galloway, T, Thomas, KV. 2022. The message on the bottle: Rethinking plastic labelling to better encourage sustainable use. Environmental Science & Policy; 132: 109-118. https://doi.org/10.1016/j.envsci.2022.02.015
• [7]. Napper, IE, Thompson, RC. 2019. Environmental deterioration of biodegradable, oxo-biodegradable, compostable, and conventional plastic carrier bags in the sea, soil, and open-air over a 3-year period. Environmental Science & Technology; 53(9): 4775-4783. https://doi.org/10.1021/acs.est.8b06984
• [8]. Chen, M, Cai, C, Bao, J, Du, Y, Gao, H, Liu, X. 2022. Effect of aliphatic segment length and content on crystallization and biodegradation properties of aliphatic-aromatic co-polyesters. Polymer Degradation and Stability; 203: 110080. https://doi.org/10.1016/j.polymdegradstab.2022.110080
• [9]. Arslan, A, Çakmak, S, Cengiz, A, Gümüşderelioğlu, M. 2016. Poly(butylene adipate-co-terephthalate) scaffolds: processing, structural characteristics and cellular responses. Journal of Biomaterials Science, Polymer Edition; 27(18): 1841-1859. https://doi.org/10.1080/09205063.2016.1239945
• [10]. Chiangga, S, Suwannasopon, S, Trivijitkasem, N. (Supreya). 2012. Thermal Degradation of Biodegradable Poly(butylene adipate-co-terephthalate)/Starch Blends. Agriculture and Natural Resources; 46(4): 653–661. https://li01.tci-thaijo.org/index.php/anres/article/view/242919.
• [11]. Van De Velde, K, Kiekens, P. 2002. Biopolymers: overview of several properties and consequences on their applications. Polymer Testing; 21(4): 433−442. http://hdl.handle.net/1854/LU-161309
• [12]. Moustafa, H, Guizani, C, Dupont, C, Martin, V, Jeguirim, M, Dufresne, A. 2076. Utilization of Torrefied Coffee Grounds as Reinforcing Agent To Produce High-Quality Biodegradable PBAT Composites for Food Packaging Applications. ACS Sustainable Chemistry & Engineering; 5(2): 1906–1916. https://doi.org/10.1021/acssuschemeng.6b02633
• [13]. Wang, X, Mo, W, Zeng, Y, Wang, J. 2024. Preparation and mechanical properties of PBAT/silanized cellulose composites. Processes; 12(4): 722. https://doi.org/10.3390/pr12040722
• [14]. Muroi, F, Tachibana, Y, Soulenthone, P, Yamamoto, K, Mizuno, T, Sakurai, T, Kobayashi, Y, Kasuya, K. 2017. Characterization of a poly(butylene adipate-co- terephthalate) hydrolase from the aerobic mesophilic bacterium, Bacillus pumilus. Polymer Degradation and Stability; 137: 11–22. https://doi.org/10.1016/j. polymdegradstab.2017.01.006
• [15]. Zhang, M, Jia, H, Weng, YX, Li, CT. 2019. Biodegradable PLA/PBAT mulch on microbial community structure in different soils. International Biodeterioration & Biodegradation; 145: 104817 https://doi.org/10.1016/j.ibiod.2019.104817
• [16]. Didovets, Y, Brela, MZ. 2022. Theoretical study on the thermal degradation process of nylon 6 and polyhydroxybutyrate. Physchem; 2(4): 334-346. https://doi.org/10.3390/physchem2040024
• [17]. Vohlídal, J. 2021. Polymer degradation: a short review. Chemistry Teacher International; 3(2): 213-220. https://doi.org/10.1515/cti-2020-0015
• [18]. Van Krevelen, DW, Te Nijenhuis, K. Properties of Polymers. In: Van Krevelen DW, Te Nijenhuis K (ed) Thermal Decomposition, 4rd edn. Elsevier, 2009, pp 763-777. https://doi.org/10.1016/B978-0-08-054819-7.00021-2
• [19]. Okoffo, ED, Chan, CM, Rauert, C, Kaserzon, S, Thomas, KV. 2022. Identification and Quantification of Micro-Bioplastics in Environmental Samples by Pyrolysis–Gas Chromatography–Mass Spectrometry. Environmental Science & Technology; 56(19): 13774-13785. https://doi.org/10.1021/acs.est.2c04091
• [20]. Falco, F. De, Nacci, T, Durndell, L, Thompson, RC, Degano, I, Modugno, F. 2023. A thermoanalytical insight into the composition of biodegradable polymers and commercial products by EGA-MS and Py-GC-MS. Journal of Analytical and Applied Pyrolysis; 171: 105937. https://doi.org/10.1016/j.jaap.2023.105937
• [21]. Rizzarelli, P, Rapisarda, M, Perna, S, Mirabella, EF, Carta, S. La, Puglisi, C, Valenti, G. 2016. Determination of polyethylene in biodegradable polymer blends and in compostable carrier bags by Py-GC/MS and TGA. Journal of Analytical and Applied Pyrolysis; 117: 72–81. https://doi.org/10.1016/j.jaap.2015.12.014.
• [22]. Huang, J, He, C, Wu, L, Tong, H. 2017. Theoretical studies on thermal decomposition mechanism of arabinofuranose. Journal of the Energy Institute; 90(3): 372–381. https://doi.org/10.1016/j.joei.2016.04.005
• [23]. Huang, J, He, C, Wu, L, Tong, H. 2016. Thermal degradation reaction mechanism of xylose: A DFT study. Chemical Physics Letters; 658: 114–124. https://doi.org/10.1016/j.cplett.2016.06.025
• [24]. Huang, J, Li, X, Zeng, G, Cheng, X, Tong, H, Wang, D. 2018. Thermal decomposition mechanisms of poly(vinyl chloride): A computational study. Waste Management; 76: 483–496. https://doi.org/10.1016/j.wasman.2018.03.033
• [25]. Younker, JM, Beste, A, Buchanan, AC. 2012. Computational study of bond dissociation enthalpies for lignin model compounds: β-5 Arylcoumaran. Chemical Physics Letters; 545: 100–106. https://doi.org/10.1016/j.cplett.2012.07.017
• [26]. Zhang, Y, Liu, C, Chen, X. 2015. Unveiling the initial pyrolytic mechanisms of cellulose by DFT study. Journal of Analytical and Applied Pyrolysis, 113: 621–629. https://doi.org/10.1016/j.jaap.2015.04.010
• [27]. Huang, J, Cheng, X, Meng, H, Pan, G, Wang, S, Wang, D. 2020. Density functional theory study on the catalytic degradation mechanism of polystyrene. AIP Advances; 10(8): 085004. https://doi.org/10.1063/5.0013211
• [28]. Martínez, A, Perez-Sanchez, E, Caballero, A, Ramírez, R, Quevedo, U, Salvador-García, D. 2024. PBAT is biodegradable but what about the toxicity of its biodegradation products?. Journal of Molecular Modeling; 30: 273. https://doi.org/10.1007/s00894-024-06066-0
• [29]. Ma, T, Wang, R, Wang, W, Gu, W, Yuan, Y, Zhang, A, Wei, J. 2022. Studies on the thermal degradation mechanism of polyethylene terephthalate and its 2-carboxy ethyl (phenyl) phosphinic acid copolymers. Polymer Degradation and Stability; 206:110185. https://doi.org/10.1016/j.polymdegradstab.2022.110185
• [30]. Huang, J, Meng, H, Luo, X, Mu, X, Xu, W, Jin, L, Lai, B. 2022. Insights into the thermal degradation mechanisms of polyethylene terephthalate dimer using DFT method. Chemosphere, 291(2):133112. https://doi.org/10.1016/j.chemosphere.2021.133112
• [31]. Shao, Y, et al. 2006. Advances in methods and algorithms in a modern quantum chemistry program package, Physical Chemistry Chemical Physics; 8: 3172-3191. https://doi.org/10.1039/B517914A
• [32]. Becke, AD. 1993. Density-functional thermochemistry. III. The role of exact Exchange. The Journal of Chemical Physics; 98: 5648–5652. https://doi.org/10.1063/1.464913
• [33]. Lee, C, Yang, W, Parr, RG. 1988. Development of the Colle-Salvetti correlation-energy formula into a functional of the electron density. Physical review. B; 37: 785–789. https://doi.org/10.1103/PhysRevB.37.785
• [34]. Gaussian 16, Revision C.01 (2016). Gaussian, Inc.
• [35]. Herrera, R, Franco, L, Rodríguez-Galán, A, Puiggalí, J.2002. Characterization and degradation behavior of poly(butylene adipate-co-terephthalate)s. J. Polym. Sci. Part A Polym. Chem; 40(23): 4141–4157. https://doi.org/10.1002/pola.10501
• [36]. Jian, J, Xiangbin, Z, Xianbo, H. 2020. An overview on synthesis, properties and applications of poly(butylene-adipate-co-terephthalate)–PBAT, Advanced Industrial and Engineering Polymer Research; 3(1): 19-26. https://doi.org/10.1016/j.aiepr.2020.01.001
• [37]. Jensen, F. Introduction to Computational Chemistry; 2nd ed. Press: Wiley, 2007.
• [38]. Atkins, P, de Paula, J. Atkins’ Physical Chemistry; 10th Edition, Press: Oxford University, Oxford, 2014.
• [39]. Coralli, I, Rombol`a, AG, Fabbri, D. 2024. Analytical pyrolysis of the bioplastic PBAT poly(butylene adipate-co-terephthalate). Journal of Analytical and Applied Pyrolysis;181: 106577. https://doi.org/10.1016/j.jaap.2024.106577
• [40]. Chen, H, Chen, F, Chen, H, Liu, H, Chen, L, Yu, L. 2023. Thermal degradation and combustion properties of most popular synthetic biodegradable polymers. Waste Management & Research; 41(2): 431–441, https://doi.org/10.1177/0734242X221129054
• [41]. Yang, Y, Min, J, Xue, T, Jiang, P, Liu, X, Peng, R, Huang, J-W, Qu, Y, Li, X, Ma, N, Tsai, F-C, Dai, L, Zhang, Q, Liu, Y, Chen, C-C, Guo, R-T. 2023. Complete bio-degradation of poly(butylene adipate-co-terephthalate) via engineered cutinases. Nature communications; 14: 1645 https://doi.org/10.1038/s41467-023-37374-3