Journal of Materials Science

, Volume 55, Issue 11, pp 4607–4623 | Cite as

The role played by different active hydrogen sources in the microencapsulation of a commercial oligomeric diisocyanate

  • Mónica V. Loureiro
  • Mahboobeh Attaei
  • Sofia Rocha
  • Mário Vale
  • João C. Bordado
  • Ricardo Simões
  • Isabel Pinho
  • Ana C. MarquesEmail author
Chemical routes to materials


The present paper regards the development of polyurea/polyurethane (PUa/PU) and PUa/PU–silica hybrid shell microcapsules (MCs), loaded with Ongronat®2500, a commercial type of oligomeric methylene diphenyl diisocyanate with increased functionality, as core material. Ongronat® 2500 has a wide range of applications either for the production of rigid polyurethane foams and as cross-linking or self-healing agent. The MCs were achieved by a facile, one-pot process, consisting of an oil-in-water microemulsion system combined with interfacial polymerization processing, employing a higher reactivity isocyanate, toluene diisocyanate, to competitively contribute to the shell formation. Ethylenediamine, polyethylenimine (PEI), triethoxy(octyl)silane (n-OTES) and 3-(2-aminoethylamino) propyltrimethoxysilane (aminosilane) were tested as active, or “latent” active hydrogen (H) sources, and their effect on the MCs morphology, encapsulation yield, shelf life, shell’s chemical structure and thermal stability was assessed. The MCs are aimed at the development of a new generation of adhesive formulations, which are mono-component, self-reactive, eco-friendly and with low health hazards, for industries such as the footwear, construction, aerospace and automotive. MCs’ characterization was performed using Fourier transformed infrared spectroscopy, thermogravimetric analysis and scanning electron microscopy. It was possible to obtain MCs with a high loading of Ongronat®2500, exhibiting a core–shell morphology, an increased shell resistance to temperature and improved shelf life. The combination of PEI and n-OTES led to the best compromise between encapsulation yield and shelf life. Finally, a confinement effect of the encapsulated macromolecules is herein shown for the first time, by the drastic narrowing of the NCO peak at the FTIR spectrum of the MCs.



This research was funded by FEDER through the COMPETE 2020 program and the Regional Operational Program of Lisbon—LISBOA2020, in the scope of the Portugal2020 Project 17930, “ECOBOND—Development of new ecological, self-reactive, monocomponent adhesives”. The authors gratefully acknowledge Fundação para a Ciência e a Tecnologia (FCT) through the support of CERENA (Strategic Project FCT-UID/ECI/04028/2019) and the Grants SFRH/BD/140700/2018 (Mónica V. Loureiro) and SFRH/BD/138717/2018 (Mário Vale).

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Supplementary material

10853_2019_4301_MOESM1_ESM.docx (663 kb)
Supplementary material 1 (DOCX 662 kb)


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© Springer Science+Business Media, LLC, part of Springer Nature 2019

Authors and Affiliations

  1. 1.CERENA, Departamento de Engenharia Química, Instituto Superior TécnicoUniversidade de LisboaLisbonPortugal
  2. 2.CQE, Departamento de Engenharia Química, Instituto Superior TécnicoUniversidade de LisboaLisbonPortugal
  3. 3.Instituto Politécnico do Cávado e do Ave – IPCA, Campus do IPCABarcelosPortugal
  4. 4.CIPADE-Indústria e Investigação de Produtos AdesivosSão João da MadeiraPortugal

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