Preprint Article Version 1 Preserved in Portico This version is not peer-reviewed

Blocking and Deblocking of Diisocyanate to Synthesize Polyurethanes

Version 1 : Received: 5 July 2021 / Approved: 12 July 2021 / Online: 12 July 2021 (11:45:26 CEST)
(This article belongs to the Research Topic Ecofriendly Materials)

How to cite: Jana, S.; Samanta, D.; Fahad, M.M.; Jaisankar, S.N.; Kim, H. Blocking and Deblocking of Diisocyanate to Synthesize Polyurethanes. Preprints 2021, 2021070247. https://doi.org/10.20944/preprints202107.0247.v1 Jana, S.; Samanta, D.; Fahad, M.M.; Jaisankar, S.N.; Kim, H. Blocking and Deblocking of Diisocyanate to Synthesize Polyurethanes. Preprints 2021, 2021070247. https://doi.org/10.20944/preprints202107.0247.v1

Abstract

Diisocyanates, particularly toluene diisocyanate (TDI) are useful for the preparation of various polyurethanes with specific applications as leather-like materials, adhesives, insoles etc. Blocking agents can be used for the operational simplicity and reducing the hazards of TDI. In this paper we reported the use of 3-(4-bromo-phenyl)-1H-pyrazole to block toluene diisocyanate (TDI). FTIR, NMR, thermogravimetric analysis, contact angle and differential scanning calorimetry (DSC) and were used for characterization. Effectiveness of blocking was confirmed by spectroscopic techniques. DSC thermogram shows that blocked adducts deblock at 240 °C causing the regeneration of TDI and blocking agents to react with polyols of different molecular weights forming polyurethanes. The characterization of polyurethanes has been done by Infrared spectroscopy, Nuclear magnetic resonance spectroscopy, thermogravimetric analysis, differential scanning calorimetry and contact angle study.

Keywords

Toluene diisocyanate; 3-(4-bromophenyl)-1H-pyrazole; blocking agent; blocked adduct; deblocks; polyol; polyurethane; coatings.

Subject

Chemistry and Materials Science, Biomaterials

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