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In this paper, we report various polyurethane nanocomposites of single‐walled carbon nanotubes using blocking–deblocking reactions. Thus, the synthesis was carried out using blocked isocyanates where, at deblocking temperature, isocyanates regenerated and reacted with polyol (PEG‐400) and single‐walled carbon nanotubes (SWCNTs) to form polyurethane nanocomposites. For example, at 185°C, regenerated (deblocked) hexamethylene diisocyanates was reacted with polyethylene glycol‐400 and SWCNT to form polyurethane nanocomposites. Similarly, at 238°C, regenerated (deblocked) toluene diisocyanates was reacted with polyethylene glycol‐400 and SWCNT to form polyurethane nanocomposites. The characterization of synthesized polyurethane nanocomposites has been done by Fourier transform infrared spectroscopy, nuclear magnetic resonance, thermogravimetric analysis, differential scanning calorimetry, field emission scanning electron microscopy, High resolution transmission electron microscopy and contact angle measurement. [ABSTRACT FROM AUTHOR]

Hexamethylene diisocyanate (HMDI) reacts with 4-bromo-1H-pyrazole as a blocking agent to form blocked adducts of isocyanates. The adducts were characterized by FTIR, NMR, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). In the FTIR spectra, disappearance of a peak at 2250–2270 cm−1 is the indication of blocking of diisocyanate molecule with 4-bromo-1H-pyrazole blocking agent. The DSC thermogram shows that at 185 °C, the blocked adduct de-blocks and HMDI and blocking agent 4-bromo-1H-pyrazole has been regenerated. At 185 °C, regenerated HMDI reacts with polyols of different molecular weights to form polyurethane. The polyurethanes were characterized by FTIR, NMR, DSC, TGA and contact angle measurements. These are useful for hydrophilic coating. [ABSTRACT FROM AUTHOR]