Self-healing epoxy coating synthesis by embedment of metal 2-methyl imidazole and acetylacetonate complexes with microcapsules

Hafeez Ullah; Khurram Shehzad Qureshi; Usama Khan; Maryam Zaffar; Yap Jen Yang; Nurul Ekmi Rabat; Muhammad Irfan Khan; Sidra Saqib; Ahmad Mukhtar; Sami Ullah; Muhammad Mubashir; Awais Bokhari; Wai Siong Chai; Kit Wayne Chew; Pau Loke Show

doi:10.1016/j.chemosphere.2021.131492

Self-healing epoxy coating synthesis by embedment of metal 2-methyl imidazole and acetylacetonate complexes with microcapsules

Chemosphere. 2021 Dec:285:131492. doi: 10.1016/j.chemosphere.2021.131492. Epub 2021 Jul 8.

Authors

Affiliations

¹ Department of Chemical Engineering, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 32610, Perak, Malaysia.
² Department of Chemical Engineering, Pakistan Institute of Engineering & Applied Science, Islamabad, Pakistan.
³ Department of Mechanical Engineering, National University of Technology, Islamabad, Pakistan.
⁴ Department of Information & Technology, University of Lahore, Islamabad Campus, Pakistan.
⁵ Department of Chemical Engineering, COMSATS University Islamabad (CUI), Lahore Campus, Lahore, Punjab, 54000, Pakistan.
⁶ Department of Chemical Engineering, NFC Institute of Engineering and Fertilizer Research, Faisalabad, Punjab, 38000, Pakistan.
⁷ Department of Chemistry, College of Science, King Khalid University, Abha, 61413, Saudi Arabia.
⁸ Department of Petroleum Engineering, Faculty of Computing, Engineering & Technology, School of Engineering, Asia Pacific University of Technology, and Innovation, 57000, Kuala Lumpur, Malaysia. Electronic address: mubashir@apu.edu.my.
⁹ Department of Chemical Engineering, COMSATS University Islamabad (CUI), Lahore Campus, Lahore, Punjab, 54000, Pakistan; Sustainable Process Integration Laboratory, SPIL, NETME Centre, Faculty of Mechanical Engineering, Brno University of Technology, VUT Brno, Technická 2896/2, 616 00, Brno, Czech Republic.
¹⁰ Department of Chemical and Environmental Engineering, Faculty Science and Engineering, University of Nottingham, Malaysia, 43500, Semenyih, Selangor, Darul Ehsan, Malaysia.
¹¹ School of Energy and Chemical Engineering, Xiamen University Malaysia, Jalan Sunsuria, Bandar Sunsuria, 43900, Sepang, Selangor, Darul Ehsan, Malaysia.
¹² Department of Chemical and Environmental Engineering, Faculty Science and Engineering, University of Nottingham, Malaysia, 43500, Semenyih, Selangor, Darul Ehsan, Malaysia. Electronic address: PauLoke.Show@nottingham.edu.my.

PMID: 34273691
DOI: 10.1016/j.chemosphere.2021.131492

Abstract

The restoration of mechanical properties is desired for creating the self-healing coatings with no corrosion capabilities. The encapsulation of epoxy resins is limited by various factors in urea and melamine formaldehyde microcapsules. An improved method was developed, where epoxy resin was encapsulated by individual wrapping of poly(melamine-formaldehyde) and poly(urea-formaldehyde) shell around emulsified epoxy droplets via oil-in-water emulsion polymerization method. The synthesized materials were characterized analytically. The curing of the epoxy was achieved by adding the [Ni/Co(2-MI)₆].2NO₃ as a latent hardener and iron acetylacetonate [Fe(acac)₃] as a latent accelerator. Isothermal and non-isothermal differential scanning calorimetric analysis revealed lower curing temperature (T_onset = 116 °C) and lower activation energies (Ea ≈ 69-75 kJ/mol). The addition of microcapsules and complexes did not adversely alter the flexural strength and flexural modulus of the epoxy coatings. The adhesion strength of neat coating decreased from 6310.8 ± 31 to 4720.9 ± 60 kPa and percent healing increased from 50.83 to 67.45% in the presence of acetylacetonate complex at 10 wt% of microcapsules.

Keywords: Adhesion strength; Epoxy resins; Flexural strength; Melamine-urea-formaldehyde; Metal imidazole complex; Self-healing.

MeSH terms

Capsules
Epoxy Resins*
Hydroxybutyrates*
Imidazoles
Pentanones

Substances

Capsules
Epoxy Resins
Hydroxybutyrates
Imidazoles
Pentanones
acetyl acetonate