Surface Modifier-Free Organic–Inorganic Hybridization To Produce Optically Transparent and Highly Refractive Bulk Materials Composed of Epoxy Resins and ZrO₂ Nanoparticles

Abstract

Surface modifier-free hybridization of ZrO nanoparticles (NPs) with epoxy-based polymers is demonstrated for the first time to afford highly transparent and refractive bulk materials. This is achieved by a unique and versatile hybridization via the one-pot direct phase transfer of ZrO NPs from water to epoxy monomers without any aggregation followed by curing with anhydride. Three types of representative epoxy monomers, bisphenol A diglycidyl ether (BADGE), 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate (CEL), and 1,3,5-tris(3-(oxiran-2-yl)propyl)-1,3,5-triazinane-2,4,6-trione (TEPIC), are used to produce transparent viscous dispersions. The resulting ZrO NPs are thoroughly characterized using dynamic light scattering (DLS), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR), and solid-state C CP/MAS NMR measurements. The results from DLS and TEM analyses indicate nanodispersion of ZrO into epoxy monomers as a continuous medium. A surface modification mechanism and the binding fashion during phase transfer are proposed based on the FT-IR and solid-state C CP/MAS NMR measurements. Epoxy-based hybrid materials with high transparency and refractive index are successfully fabricated by heat curing or polymerizing a mixture of monomers containing epoxy-functionalized ZrO NPs and methylhexahydrophthalic anhydride in the presence of a phosphoric catalyst. The TEM and small-angle X-ray scattering measurements of the hybrids show a nanodispersion of ZrO in the epoxy networks. The refractive index at 594 nm ( n) increases up to 1.765 for BADGE-based hybrids, 1.667 for CEL-based hybrids, and 1.693 for TEPIC-based hybrids. Their refractive indices and Abbe's numbers are quantitatively described by the Lorentz-Lorenz effective medium expansion theory. Their transmissivity is also reasonably explained using Fresnel refraction, Rayleigh scattering, and the Lambert-Beer theories. This surface modifier-free hybridization provides a versatile, fascinating, and promising method for synthesizing a variety of epoxy-based hybrid materials.

Superhydrophobic materials used for anti-icing Theory, application, and development

“…(3) Using hydrophobic nanoparticles to fabricate free-standing particle-polymer composites ( Wang et al., 2021b ). When the SHS is worn away or removed, a new layer of SHS will be formed ( Enomoto et al., 2018 ). In this way, it can greatly extend the use time of SH materials.…”

Zirconium dioxide@phosphazene for enhancing mechanical property, flame retardancy, and thermal property of polythiourethane composites

“…[18][19][20][21][22] Several strategies for introducing ZrO 2 into the polymer matrix have emerged; these include physical addition and in-situ polymerization. 19,[23][24][25][26] Compared with the latter, the former has the advantages of economy, simple operation and mild conditions, and has been widely adopted by numerous researchers. However, due to the deformation incompatibility and the shortcomings of ZrO 2 being easy to agglomerate, severe stress concentration and poor dispersibility could be easily induced in the polymer network structure, resulting in the degradation of polymer performance.…”

Dispersions of Zirconia Nanoparticles Close to the Phase Boundary of Surfactant-Free Ternary Mixtures

“… 20 As an example, the surface treatment of nanoparticles in inorganic–organic composites leads to decreases of the optical properties. 21 Finally, the addition of different chemical agents alter the viscosity properties. 22 For these reasons, the development of new strategies to get homogeneous nanoparticle distribution, by avoiding surface capping or functionalization, represents an attractive challenge.…”