Effect of Zn-based Colorants on the Hydrolytic Degradation of PBT and Corrosion of Aluminum

Sang Soo Jeon; Byung Su Kim; Jeon Mo Choi; Kang Il Jeon

doi:10.22680/kasa2026.18.2.063

All Issue

2026 Vol.18, Issue 2 Preview Page Next Page

Effect of Zn-based Colorants on the Hydrolytic Degradation of PBT and Corrosion of Aluminum PBT의 가수분해와 알루미늄 부식에 미치는 Zn 안료의 영향

30 June 2026. pp. 63-70

PDF XML

Abstract

In this study, the effects of Zn-based colorants on plastic degradation and the corrosion of metals in contact with degraded plastics were investigated. Poly (butylene terephthalate) (PBT) and Polyamide6,6 (PA66) were used as base resins and compounded with ZnO, ZnS, and TiO₂ as white colorants. It was confirmed that the flexural strength dramatically decreased under accelerated conditions of 130℃ and 85% RH only when ZnS or ZnO was added to the ester-based PBT compounds. Under high temperature and humidity conditions, the added Zn-based colorants acted as strong Lewis acids in the form of Zn²⁺ ions, thereby accelerating the hydrolysis of PBT. FT-IR spectroscopy and end-group analysis of the degraded PBT confirmed that the ester linkages were depolymerized to generate carboxylic acids. Carboxylic acids derived from PBT degradation attacked contacting aluminum, causing surface corrosion and the release of Al³⁺ ions. This process eventually resulted in the formation of white aluminum oxides and aluminum hydroxides, such as Al₂O₃ and Al(OH)₃. Furthermore, the Al³⁺ ions released during corrosion acted as Lewis acid catalysts, similar to Zn²⁺ ions, thereby accelerating the degradation of PBT. In conclusion, the catalytic degradation of PBT by Zn-based colorants and the corrosion mechanism of aluminum induced by the carboxylic acids from degraded PBT were chemically elucidated. Based on these findings, material specifications were updated to prohibit the use of Zn-based colorants in ester-based plastics.

Keywords

Polybutylene terephthalate(PBT)

Zinc sulfide(ZnS)

Zinc oxide(ZnO)

Depolymerization(분해)

Corrosion (부식)

References

최기대, 2009, “엔지니어링 플라스틱 기술 동향”, 고분자 과학과 기술, vol. 20, No.1, pp. 3~7.

Pyda, M., Nowak-Pyda, E., Heeg, J., Huth, H., Minakov, A. A., Dilorenzo, M. L., Schick, C. and Wunderlich, B., 2006, “Melting and Crystallization of Poly(butylene terephthalate)by Temperature-Modulated and Superfast Calorimetry”, Journal of Polymer Science: Part B: Polymer Physics, vol. 44, pp. 1364~1377.

10.1002/polb.20789

Loyer, C., Regnier, G., Duval, B. and Richaud, E., 2021, “Multiscale Study of Poly(butylene terephthalate) hydrolysis”, Polymer Degradation and Stability, vol. 192, No. 109690, pp. 1~19.

10.1016/j.polymdegradstab.2021.109690

Cucciolito, M. E., Lega, M., Papa, V. and Ruffo, F., 2016, “Simple Zn(II) Salts as Efficient Catalysts for the Homogeneous Trans-Esterification of Methyl Esters”, Catalysis Letters, vol. 146, pp. 1113~1117.

10.1007/s10562-016-1733-6

Nagvenkar, A., Naik, S. and Fernandes, J., 2015, “Zinc oxide as a Solid Acid Catalyst for Esterification Reaction”, Catalysis Communications, vol. 65, pp. 20~23.

10.1016/j.catcom.2015.02.009

Hofmann, M., Sundermeier, J., Alberti, C. and Enthaler, S., 2020, “Zn(II) Acetate Catalyzed Depolymerization of Poly(ethylene terephthalate)”, ChemistrySelect, vol. 5, pp. 10010~10014.

10.1002/slct.202002260

Max, J. J. and Chapados, C., 2004, “Infrared Spectroscopy of Aqueous Carboxylic Acids: Comparison between Different Acids and Their Salts”, The Journal of Physical Chemistry A, vol. 108, No. 16, pp. 3324~3337.

10.1021/jp036401t

Campanelli, J. R., Kamal, M. R. and Cooper, D. G., 1994, “Kinetics of Glycolysis of Poly(ethylene terephthalate) Melts”, Journal of Applied Polymer Science, vol 54, Issue 11, pp. 1731~1740.

10.1002/app.1994.070541115

Loyer, C., Regnier, G., Duval, V. and Richaud, E., 2021, “Multiscale Study of Poly(butylene terephthalate) Hydrolysis”, Polymer Degradation and Stability, vol. 192, pp. 109690~109698.

10.1016/j.polymdegradstab.2021.109690

Information

Publisher :Korean Auto-vehicle Safety Association
Publisher(Ko) :한국자동차모빌리티안전학회
Journal Title :Journal of Auto-vehicle Safety Association
Journal Title(Ko) :자동차안전학회지
Volume : 18
No :2
Pages :63-70
Received Date : 2026-04-03
Revised Date : 2026-05-18
Accepted Date : 2026-05-19
DOI :https://doi.org/10.22680/kasa2026.18.2.063

Journal of Auto-vehicle Safety Association ISSN:2005-9396(Print) 자동차안전학회지

All Issue