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Novel hybrid poly(dimethylsiloxane) urethanesils produced by CO2 fixation present multifunctional properties for metallic and inorganic surfaces.

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Over the past three decades, researchers have investigated the existence of possible relationships between crystal nucleation kinetics and the atomic-scale structure of silicate glasses. The main driving force for this quest was the fact that while the vast majority of glass-forming substances only undergo surface (heterogeneous) nucleation when sufficiently heated, a few systems also show the thermodynamically less favourable case of internal (homogeneous) nucleation on laboratory time/length scales. For such glass systems, various macroscopic properties, such as densities, configurational entropies and frozen-in birefringence, have suggested that the structure in the glassy state shows a closer resemblance to the structure of the phase formed upon crystallisation than in the case of glass systems only undergoing heterogeneous nucleation. However, the specific structural features and their length scales have remained uncertain. In this article, we review and discuss the research investigating relationships between the occurrence of internal nucleation and structural parameters related to various different length scales. The latter include (1) short-range order, concerning both network modifier cation-oxygen distances and coordination numbers as well as network former Q n distributions, (2) intermediate range order describing network former connectivities, network former/network modifier correlations, and network modifier distance distributions, and (3) medium range order as reflected by silicate tetrahedral ring-size statistics. Inspection of this data for several stoichiometric oxide glasses and their respective isochemical crystals suggests a positive correlation between homogeneous nucleation ability and structural similarity at the level of short-and intermediate-range order of the network modifier cations. In contrast, no correlation can be found with regard to any structural parameters describing the local structures of the network former species (Q n distributions). Based on the limited set of data available, we develop concrete recommendations for future experiments to test this hypothesis.

High‐resolution solid‐state 31P, 27Al, and 23Na nuclear magnetic resonance (NMR), Raman spectroscopy, differential scanning calorimetry, and density measurements were used to characterize the local structure of the glasses (1−x)(NaPO3)3·xAl(PO3)3. A systematic increase in density, glass transition temperature (Tg), and frequencies of P–O stretching vibrations for terminal nonbridging oxygens (NBOs) was observed as the Al content was increased. A change of slope in the behavior of Tg as a function of x was clearly detected around x= 0.25 ± 0.03. Also, changes of behavior in the 23Na NMR line shape and in the Raman band of the PO2 symmetric vibration are detected for concentrations higher than x= 0.17. According to these facts, a reorganization of the network affecting the degree of connectivity between phosphate chains is proposed to explain the observed behaviors of Tg and P–NBO vibrations in these glasses.

The effect of activators on the hydration of granulated blast‐furnace slag (gbfs) was studied through compressive strength measurements, 29Si, 27Al, and 23Na high‐resolution nuclear magnetic resonance, and X‐ray diffraction. Four different activations containing sodium hydroxide, sodium silicate, and/or calcium hydroxide (CH) were considered, at fixed amounts of alkali: 5% Na2O, 5% Na2O‐2.5% CH, 5% Na2O‐7.5% SiO2, and 5% Na2O‐2.5% CH‐7.5% SiO2. Silicate‐activated gbfs cements have greater compressive strength than Portland cements over the whole period of study (1 yr). Also, silicate‐free activated gbfs cements have poorer mechanical strength than silicate‐activated cements. In fact, substantial structural differences were observed between hydration products in both kinds of activations. In silicate‐activated pastes there exists an intimate mixture of C‐S‐H layers and AFm‐like arrangements containing Al in octahedral sites bonded to the silicate layers, originated either from phase intergrowths or from a high density of Ca‐Al incorporation in the interlayer spaces of C‐S‐H. In pastes obtained from silicate‐free activation of gbfs there is a better chemical and structural definition among C‐S‐H and calcium aluminate hydrate domains (AFm and hydrogarnet).