Highly branched graphene siloxane−polyurethane-urea (PU-urea) hybrid coatings

Here, we report the development of waterborne hybrid coatings containing Si[sbnd]O[sbnd]Si and Si[sbnd]O[sbnd]C groups were obtained by using amino functionalized chemically reduced graphene nanoparticles (APTES-CRG), amino functionalized Zinc Oxide nanoparticles (APTES-ZnO), isophorone di-isocyanate (IPDI), polyether polyol (PTMG1000), and dimethylol propionic acid (bis-MPA) as main materials. The test results indicated that the siloxane network was developed during the functionalization reaction and film curing. The effects of APTES-ZnO and APTES-CRG content on the properties of the films were studied. The morphology results from TEM analysis show that APTES-ZnO and APTES-CRG nanoparticles were homogeneously distributed in waterborne hybrid coatings. The tensile strength increases from 9.6 MPa to 15.8 MPa when the APTE-ZnO content increases from 0% to 15% and from 9.6 MPa to 20.3 MPa when the APTE-CRG content increases from 0% to 15%. TGA analysis indicates that the APTES-ZnO and APTES-CRG improves the thermal stability of the coatings. Conductivity of the graphene hybrid coatings was measured by two probe methods showed 1.34 × 10–8 S/cm, which is 10 orders of magnitude higher than that of WPU base (2.37 × 10–18 S/cm) (insulator level, < 10–12 S/cm).