Influence of the association of hydrophobic end groups on the temperature insensitivity of HEUR-thickened latex/Fe2O3/Zn3(PO4)2/BaSO4 suspensions

Hydrophobically modified ethoxylated urethane (HEUR) with different structures was synthesized and confirmed by gel permeation chromatography, Fourier transform infrared spectroscopy and nuclear magnetic resonance ( 1 H NMR). We propose the relationship between the temperature insensitivity model and the thickening mechanism of HEUR/latex/Fe 2 O 3 /Zn 3 (PO 4 ) 2 /BaSO 4 suspensions. Meanwhile, the temperature insensitivity of HEUR/C suspensions is the result of two main associations: intermolecular interactions bridging the hydrophobic tails of HEURs and the hydrophobic groups tightly adsorbing onto the latex particle surfaces. A smaller ratio of viscosity (Rv) at 1 s −1 from the steady state condition indicates the better temperature insensitivity of viscosity. The higher degree of crystallinity and rheological activation energy corresponds to a great extent with better temperature insensitivity due to stronger association. The temperature insensitivity is consistent with the longer hydrophobic chain, which was proven by hysteresis tests and oscillatory shear measurements. The storage stability was enhanced in the lockstep with a hydrophobic length of HEUR, which is consistent with the rougher surfaces of HEUR/C films. As an appealing method, the results are meaningful and instructive for coating storage and application. Graphical abstract An intermolecular network model of HEUR/C is presented, which suggests intermolecular associations in the bridging of hydrophobic tails and the hydrophobic groups adsorbing onto the latex particle surfaces. A temperature insensitivity mechanism model combined with rheology results and AFM is also proposed to clarify the relationship between temperature insensitivity and storage stability and the hydrophobic tail length.