Self-Organization, Structure, Dynamic Properties, and Surface Morphology of Silica/Epoxy Films As Seen by Solid-State NMR, SAXS, and AFM

Abstract

The high degree of self-assembling of epoxide-based products made from functionalized organosilica building blocks, functionalized oligo(oxypropylene)-diamine and/or -triamine, and colloidal silica nanoparticles was evidenced by solid-state NMR spectroscopy, small-angle X-ray scattering (SAXS), and atomic force microscopy (AFM). Under optimized conditions of preparation, isolated siloxane cagelike clusters arise in the reaction mixture. No cleavage of oxirane rings occurs before thermal curing, and thus the whole process is well controlled. The presence of silica nanoparticles accelerates the kinetics of polycondensation and affects the condensation rate of siloxane units in final products. Two-dimensional solid-state NMR experiments (2D CRAMPS, 2D 1H−13C and 1H−29Si HETCOR, WISE) revealed differences in structure and segmental dynamics of final films as well as in self-organization and homogeneity degree depending on reaction conditions. Ideally, siloxane cagelike clusters are regularly dispersed within the bulk and oxypropylene chains form phase which separates organic tails of siloxane clusters. The SAXS determined distance between clusters (1.8 nm) well corresponds to the constraints determined by NMR spin-diffusion experiments. Polymer interaction with silica nanoparticles is confirmed by two-dimensional 1H−29Si HETCOR experiments.

The influence of nanoadditives on surface, permeability and mechanical properties of self-organized organic–inorganic nanocomposite coatings

“…2a and Table 1) in the rubbery state were high, in the order of 10 7 Pa. The highest modulus in the rubber state was observed for the film with colloidal silica as nanofiller, obviously due to some covalent bonding (silanol condensation) between the filler and the O-I matrix 15 (both contain silanol groups). The sample modified by Laponite (LX), in which only 80% conversion of the epoxy-amino crosslinking reaction was observed, showed expectedly a lower modulus in rubber state.…”

“…9,10,[12][13][14] Recently we prepared and characterized series of O-I nanocomposite coatings with inorganic filler prepared by both above-mentioned methods, i.e., inorganic structure in situ built-up and nanofiller addition. As filler, colloidal silica was used in the concentration from 5 to 20 wt% [15][16][17][18][19] and montmorillonites at concentration from 1 to 5 wt%. [18][19][20] The present work is aimed at studying the effect of a really small inorganic nanofiller amount, 0.5 wt%, in composites with an organic inorganic hybrid matrix.…”

Preparation of Novel Hydrolyzing Urethane Modified Thiol-Ene Networks

“…In this approach, metal oxides undergo various stages of hydrolysis and sequential polycondensation reactions, ultimately producing gels suitable for applications in polymeric materials [5][6][7][8][9][10], optics [7], biomaterials, and glassy or ceramic like coatings [11,12]. Tetraethyl orthosilicate (TEOS) has been widely explored using sol-gel techniques since the 1880s [8].…”

BaSO4‐, CaF2‐, and Al‐Maleate‐Derived Nanocomposite Coatings with Excellent Mechanical, Thermal, and Optical Properties

“…The design of nanocomposites prepared from dispersions of inorganic or organometallic particles within organic matrices aims on materials and/or surfaces with enhanced scratch, abrasion, solvent and heat resistance, high transparency, toughness, and stiffness as well as gas permeability, to list just a few. [1][2][3][4][5][6][7][8][9] The final properties of a given nanocomposite depend largely on the nature and size of the nanoparticles used, the quality of the dispersion of these nanoparticles within the polymeric matrix as well as on the chemistry with which these nanoparticles have been connected to the polymeric matrix. Purely hydrophilic inorganic nanoparticles, on the one hand, are hard to disperse into hydrophobic polymers.…”