Abstract
The research was planned to test electrical properties of polymer films made from polyurethane cationomers with 0–2 wt.% graphene admixture. The cationomers were synthetized in the reaction of 4,4′-methylenebis(phenyl isocyanate), polycaprolactone diol (M = 2000), N-methyldiethanolamine, and formic acid. It was found that addition of approx. 2 wt.% of graphene causes the loss of volume resistivity by three orders of magnitude and percolation threshold is already set at approx. 1 wt.%. The frequency characteristic of a real part of permittivity ε′ and imaginary part of permittivity ε″ were measured for the tested films. On the base of Havriliak–Negami equation, parameters of relaxation functions in frequency domain were estimated for samples containing various contents of graphene. The influence of the cationomer phase structure on observed changes of dielectric losses coefficient tgδ in the full-measuring frequency spectrum was discussed.
Highlights
In the part I of the paper [1] synthesis, physicomechanical and thermal properties of films made of polyurethane cationomers modified with graphene in the amount of 0.5–2 wt.% were described
It was found that the presence of graphene results in increased thermal and mechanical strength of received polymer films and contributes to the increase in hydrophobicity of generally hydrophilic coatings prepared from waterborne polyurethane cationomers [1]
The previously tested polymer film which was obtained from anionomer polyurethane synthesized from MDI, polyoxypropylene diol (M = 450) and 2, 2-bis(hydroxymethyl)propionic acid (DMPA) had the volume resistivity of 1011 Ω m [12]
Summary
In the part I of the paper [1] synthesis, physicomechanical and thermal properties of films made of polyurethane cationomers modified with graphene in the amount of 0.5–2 wt.% were described. Appropriate suspensions (with calculated quantity of graphene (0.024–0.484 g) in THF (7.5 cm3) were obtained in the process of sonication at 50 °C for 30 min in ELMA SONIC P ultrasonic bath at a frequency of 80 kHz. It was found that the presence of graphene results in increased thermal and mechanical strength of received polymer films and contributes to the increase in hydrophobicity of generally hydrophilic coatings prepared from waterborne polyurethane cationomers [1].
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