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The very early hydration behavior of a hydraulic binder phase, ye’elimite, Ca4Al6O12SO4, in the absence and in the presence of calcium sulfate, has been investigated. A time-resolved in situ multin...

In this paper, a perfluoropolyether (PFPE) micellar solution was effectively deposited on metallic substrates using a dip-coating process to enhance brass and nickel aluminum bronze (NAB) corrosion resistance. Particular attention was paid to the aesthetic results as well. Enabling the metallic substrates hydrophobic to facilitate water and moisture removal was the key concept of this work. The corrosion resistance of the as-received and coated metals was investigated via a salt spray chamber test. The study focused on the characterization of the polymeric coating via dynamic light scattering and wettability tests, while the substrates were assessed with traditional metallographic techniques. The preparation of the polymeric solution was important in determining the final corrosion resistance of the two substrates. Noteworthy was the effectiveness of the PFPE-based coating when it was applied to the brass rather than the NAB. Moreover, the polymer concentration of the dip-coating polymeric emulsion was the most significant factor to obtaining adequate protection: higher polymer concentrations resulted in a decrease in corrosion resistance.

Mechanical properties such as the Young modulus, shear modulus and Poisson’s coefficient are very important to define different materials applications, for basic research and for quality control procedures. Impulse excitation technique (IET) is a non-destructive, easy and fast method for characterization of elastic and acoustic properties of materials. The technique consists in sending a mechanical impulse in a sample and measuring the output sound wave. Commercial instruments are widely spread in metal industry, but they are not diffused in academic research centres. Such instruments can be easily self-built at low cost, allowing a much wider diffusion and exploitation in many fields involving materials characterization, since they guarantee high precision and high data reproducibility. For a proper acoustic characterization, necessary to obtain reliable mechanical data, a calibration of the instrument must be performed, for a proper association of the acoustic response to the features of each specific material. In this data article, a data set of impulses, collected on different materials by a self-built instrument for IET, named IETeasy, is provided for mechanical properties characterization by a self-built IET tool, and multivariate statistical analysis purposes. The aim is double in the short term: on one hand, providing a verified data set useful to develop, test and verify methods of analysis and tailor the IETeasy instrument on the needs of each specific user; on the other hand, giving a benchmark for any one designing, building and testing his IET home-made instrument. In the long term, since the data base is open, any contribution consisting in data collected by similar self-made or commercial instruments can be added to the data base, with the aim of building a large collection of data, useful for automatic recognition of sound outputs by machine learning or other multivariate or monovariate data analysis approaches, and for instrument performance comparison and alignment.

In the past twenty years, impulse excitation technique (IET) has become a widely diffused non-destructive technique in metal industry field. This success resides in its capability to determine with high precision and accuracy some elastic properties of materials, such as Young’s modulus, shear modulus and Poisson’s ratio. The technique, which is very fast and non-destructive, consists in exciting a sample by a mechanical input and registering the acoustic output that, once analyzed by Fast Fourier-Transformation (FFT), provides the resonant frequencies of the sample, with a fast data analysis procedure. The approach is thus very easy to be applied to most materials and cost and time effective. Despite these many advantages, IET is still an under exploited technique in academic research centres, that mainly rely on traditional destructive methods for the evaluation of such properties, for instance by the measurement of strain-stress curves. Commercial IET instruments, similarly to traditional ones, have costs spanning from many hundreds to thousands of dollars, limiting their diffusion in academic world but also in small companies with limited R&D or quality control expenses. Non-professional instruments can also give very precise results and can be successfully used in basic research and in quality control even if not certified as commercial ones. Moreover they can be easily customized according to specific user needs and sample features. Since no examples of low cost IET designs can still be found in the scientific literature, we fill the gap in this paper, giving instructions for a self-assembled instrument for IET analysis, with a cost in the range of 70–85 USD. Moreover, the collected calibration data are analyzed to prove that the instrument can be used for other purposes than the common elastic properties determination, but also for a fast and cheap material characterization exploiting a multivariate analysis approach. Calibration results show that IETeasy can be used in both academic and industrial field for quality control purposes as a low-cost, fast and efficient alternative to tensometers. Principal component analysis, applied in this paper for the first time to IET data analysis, was able to distinguish and classify steel from Al or Cu alloys from polymers, but also different steel grades, demonstrating its potential in massive and eventually automatic IET data analysis. Calculated mechanical properties fitted with good approximation the ranges expected for each sample.

This manuscript deals with the thermal and chemical modification of a natural kaolinite that shows excellent performance in the capture of a cationic organic pollutant from the aqueous phase. Kaolinite was calcined at 700 °C and treated with HCl to remove aluminium and to obtain a siliceous material. The structural changes and the physico-chemical properties of the materials at different stages of thermal and chemical modification were investigated with several techniques, including XRPD, MAS-NMR, SEM-EDX, FT-IR, and N2 physisorption at 77 K. The ability of the parent kaolinite and siliceous material to capture the organic dye, Rhodamine B, from the aqueous phase was investigated by means of UV-Vis spectroscopy. The siliceous material exhibited better adsorption capacity with respect to the parent kaolinite. Finally, the functional stability of the siliceous material was tested over three cycles of regeneration and adsorption.

The paper addresses the carbonation of CSA based binders from the mechanical, chemical and mineralogical point of view. Three different binders have been investigated, revealing that many hydrated phases can protect ettringite against carbonation. In particular, the presence of AFm phases gives a significant contribution to buffer the pH in alkaline range and to preserve the protective film of steel reinforcement bars. In a carbonated environment AFm phases act as ionic exchangers: carbonate ions replace sulfates in the interlayer and in these conditions the released sulfate ions contribute to the formation of new ettringite, with a beneficial effect on compressive strength performances. Experimental data are compared with models and carbonation mechanisms are described.

Hydrotalcites are layered double hydroxides (LDHs) of the anionic clay family. They can be obtained by synthesis, with high purity and controlled stoichiometry but with much larger preparation efforts and costs with respect to natural ores. Their properties can be tailored by changing the metals of the layer, or by inserting proper inorganic or organic anions. The reason of the few industrial applications of LDHs might be the difficulty of scaling up their synthesis and anion exchange methods, requiring often cumbersome procedures for filtering, recovery and purification of the final products. Recently, huge efforts were made to obtain facile and easily scalable preparation methods, especially favoured by the almost complete elimination of solvents and water-based procedures. The structures of the nanocomposites were studied by several techniques, from electron microscopy and diffraction to X-ray powder diffraction (the unique structural techniques able to face the low crystallinity of these materials) coupled with others, to obtain an exhaustive view of LDHs structure and reactivity. These advancements and the perspectives of larger LDHs industrial applications are described.

Pharmaceutical active compounds, including hundreds of different substances, are counted among the emerging contaminants in waterbodies, whose presence raises a growing concern for the ecosystem. Drugs are metabolized and excreted mainly through urine as an unchanged active ingredient or in the form of metabolites. These emerging contaminants are not effectively removed with the technologies currently in use, making them a relevant environmental problem. This study proposes the treatment of urine and water at the source that can allow an easier removal of dissolved drugs and metabolites. The treatment of synthetic urine, with dissolved ibuprofen as a model compound, by adsorption, using various classes of inorganic materials, such as clays, hierarchical zeolites and ordered mesoporous silica (MCM-41), is presented. A multi-technique approach involving X-ray powder diffraction, solid-state NMR, UV-Vis and Raman spectroscopies was employed to investigate the adsorption process in inorganic adsorbents. Moreover, the uptake, the ensuing competition, the efficiency and selectivity as well as the packing of the model compound in ordered mesoporous silica during the incipient wetness impregnation process were all thoroughly monitored by a novel approach, involving combined complementary time-resolved in situ 1H and 13C MAS NMR spectroscopy as well as X-ray powder diffraction.

The microbial colonization of plastic wastes has been extensively studied in marine environments, while studies on aged terrestrial wastes are scarce, and mostly limited to the isolation of plastic-degrading microorganisms. Here we have applied a multidisciplinary approach involving culturomics, next-generation sequencing analyses and fine-scale physico-chemical measurements to characterize plastic wastes retrieved in landfill abandoned for more than 35 years, and to assess the composition of bacterial communities thriving as biofilms on the films’ surfaces. All samples were characterized by different colors but were all of polyethylene; IR and DSC analyses identified different level of degradation, while FT-Raman spectroscopy and X-ray fluorescence further assessed the degradation level and the presence of pigments. Each plastic type harbored distinct bacterial communities from the others, in agreement with the differences highlighted by the physico-chemical analyses. Furthermore, the most degraded polyethylene films were found to host a bacterial community more similar to the surrounding soil as revealed by both α- and β-diversity NGS analyses. This work confirms the novel hypothesis that different polyethylene terrestrial waste samples select for different bacterial communities, and that structure of these communities can be correlated with physico-chemical properties of the plastics, including the degradation degree.

The exact recipe to prepare the ancient Maya Blue (MB), an incredibly resistant and brilliant pigment prepared from indigo (dye) and Palygorskite (clay), is lost to the ages. To unravel the key features of the MB formation process, several inorganic-dye couples were heated to 200 degrees C and cooled to RT, to investigate their reactivity and the diffusion and degree of sequestration of the dye into the inorganic host. In situ XRPD/PDF and fiber optic reflectance spectroscopy (FORS) data, along with TGA, provided a comprehensive overview on MB formation mechanism. XRPD/PDF gave information on long/short range behaviors of water desorption/adsorption and indigo sequestration, while TGA and in situ FORS gave information on mass and optical changes within temperature. Ex situ dye removal was used to understand the sample stability after the thermal treatment. A statistical approach based on principal component analysis was exploited to efficiently and jointly analyze the approximate to 3000 collected patterns. MB formation starts below 110 degrees C with disordered distribution of indigo within the channels, reaching maximum reaction speed and higher ordering at 150 degrees C. Above 175 degrees C, color changes and a stronger sequestration of indigo into framework channels are observed, whereas the affinity for water is dramatically reduced. The origin of different colors, hues, and stability in historical MB samples can then be explained in terms of different thermal histories of the starting mechanical indigo/palygorskite mixtures.

The identification of affordable healing agents for cement based materials, able to promote autonomous crack healing, is a challenge to improve the durability of building structures. In this study, a thorough investigation of the reactivity between a hydrated Portland cement and sodium silicate solutions, as healing agents, has been carried out. The goal is to quantitatively assess the chemical reactivity and actual binding capacity of sodium silicate. Mechanical recovery was evaluated by means of a healing agent strength test on hydrated cement treated with sodium silicate. XRPD and Solid-state NMR allowed the definition of reaction times, the involved species, and the nature and stability of the reaction products. Highlights show that sodium silicate reacts not only with Ca(OH)2 (namely portlandite), but also with calcium aluminate phases (AFt, AFm, TAH) to extract calcium and/or aluminum ions, with the formation of crystalline/semi-crystalline C-S-H/C-A-S-H tobermorite phase.

The hydration of four sulfoaluminate cements have been studied: three sulfoaluminate systems, having different content of sulfate and silicate, and one blend Portland-CSA-calcium sulfate binder. Hydration was followed up to 90 days by means of a combination of X-ray diffraction and solid state MAS-NMR; Differential scanning calorimetry and Scanning electron microscopy were also performed in order to help the interpretation of experimental data. High amount of amorphous phases were found in all the four systems: in low-sulfate cements, amorphous part is mainly ascribed to monosulfate and aluminium hydroxide, while stratlingite is observed if belite is present in the cement; in the blend system, C-S-H contributes to the amorphous phase beyond monosulfate.

The study addresses the hydration behavior of different sulfoaluminate clinkers produced in a pilot kiln at burning temperature comprised between 1150 and 1300 °C. The clinkers contain different relative amount and distribution of sulfates and silicates. The hydration behavior from 4 h up to 3 months has been investigated by means of a multi-technique approach. The results indicate that two contributions regulate the different reactivity of these sulfoaluminate clinkers. On one hand, the presence of a readily-available sulfate source allows the faster development of ettringite, whereas, the reactivity of silicate component takes the advantage of the lack of sulfate. Moreover, the first effect influences the early reactivity, while the second one is observed only when medium to long term hydration behavior is considered. Low-temperature sulfoaluminate clinker showed similar performances in comparison with a high-temperature clinker, however, a significant reduction in burning energy (temperature is 150 °C lower) and CO2 emissions (limestone is 5% less) are envisaged.

A graphene-containing LDH was prepared by re-hydration of the oxides produced by the calcination of an organic LDH. While the memory effect is a widely recognized effect on oxides produced by inorganic LDHs, it is unprecedented from the calcination/re-hydration of organic ones. Different temperatures (400, 600 and 1100 °C) were tested, on the basis of thermogravimetric data. Water instead of a carbonate solution was used for the re-hydration, with CO2 available from water itself and/or air to induce a slower process with an easier and better intercalation of the carbonaceous species within the layers. The samples were characterized by X-ray Powder Diffraction (XRPD), IR and Raman spectroscopy and scanning electron microscopy (SEM). XRPD indicate the presence of carbonate LDH mixed with a layered phase with a larger d-spacing. IR confirmed that the prevailing anion is carbonate, coming from the water used for the re-hydration and/or air. Raman data indicated the presence of low-ordered graphenic species moieties and SEM the absence of separated graphene of graphitic sheets, suggesting an intimate mixing of the carbonaceous phase with reconstructed LDH. Organic LDHs gave better memory effect after calcination at 400 °C. Conversely, the graphenic species are observed after rehydration of the sample calcined at 600 °C with a reduced memory effect, demonstrating the interference of the carbonaceous phase with LDH reconstruction and the bonding with LDH layers to form a graphene-LDH nanocomposite.

The possibility of exploiting a thermally-induced solid-state reaction to obtain the formation of a fluorene and TCNQ molecular complex was proposed by some of us (Kumar et al., Cryst. Growth Des., 2009, 9(8), 3396-3404). In this paper, we generalize and rationalize the approach to other charge transfer (CT) molecular complexes with naphthalene and anthracene, changing the size of the donor moiety to propose a general approach for the preparation of this class of materials by exploiting the solid-state synthesis method. Moreover, the kinetic features of the solid state reactions were fully elucidated by Raman spectroscopy and high resolution X-ray Powder Diffraction analysis (in situ Raman/XRPD), exploiting the Avrami equation in isothermal and non-isothermal conditions; rate constants, reaction orders and activation energies were obtained. All the three tested solid-state charge transfer (SS-CT) reactions obeyed a general rule, whereby the most apt reaction temperature was predicted. Finally, a method based on principal component analysis (PCA) for a fast kinetic analysis of in situ XRD synchrotron data was successfully developed, employing a formalism suitable for the analysis of non-isothermal reaction data, thus allowing a high throughput approach for the fast screening of the kinetics of parent reactions. PCA analysis was exploited as an alternative technique to obtain kinetic information in a faster and more efficient way, which can be used for online monitoring and/or in all those cases where Rietveld analysis is not feasible.

The liquid-assisted grinding (LAG) method was employed for the preparation of low cost, stable, and efficient functional materials, based on organic molecules intercalated into hydrotalcite (LDH). LAG is here exploited to produce hybrid materials with facile preparation methods, low solvent consumption, short reaction times, and high yields, and to allow an easy scale up of the synthesis to industrial production. Six molecules were tested to assess potentialities and limitations of LAG. The experiments showed a significant sensitivity to the molecular nature of the intercalant, resulting in different final yields and also different physical forms of the products (powdery vs pasty materials). With 2-naphtalenesulfonic acid (2-NSA), where the standard recipe gives a yield of about 50%, experimental procedures were optimized by design of experiment (DoE) and simplex chemometric techniques to find the optimal intercalation conditions, reaching 76% of yield. A chemometric-driven strategy with wide applicabilit...

Construction and demolition waste (CDW) recycling is generally limited to the use of the coarser fraction as aggregate for new concrete. The recovery of fine aggregates requires a cleaning by removing the hydrated cement waste (HCW). In this paper, the possibility to use HCW extracted from CDW as alternative component for the production of new clinker is explored. A pure HCW sample was prepared and used in partial replacement of natural materials in raw admixtures for new clinker production. At a replacement degree of 30%, a new Portland clinker containing almost 50% of C3S could be produced with a huge spare in the release of CO2 (about 1/3 less). At higher HCW dosage a non-Portland clinker containing almost 80% of C2S has been obtained: its use as supplementary cementing material in blended cements revealed satisfying long term performances.

The chemical combination of completely condensed polyhedral oligomeric silsequioxanes and Eu3+ ions has allowed the preparation of a novel robust mesoporous silica (Eu-MesoPOSS) with interesting luminescent properties and good hydrothermal and photobleaching stability. These properties make Eu-MesoPOSS a potential candidate for the fabrication of stable and efficient luminescent devices, and a multifunctional platform for bio-imaging applications.

The study of the chemistry of materials containing Si–O bonds was in the past mainly applied to both inorganic silica and minerals or to organic silicones field in which the R2SiO unit dominates. However, in the last decade, the field of silsesquioxane chemistry with general composition RSiO3/2 has grown dramatically and many structures have been proposed in the literature. The idea of this chapter is to make an overview of the main synthetic approaches used to prepare completely and partially polyhedral oligomeric silsesquioxanes (POSS), highlighting the advantages and the weakness of each procedure. A brief description of the characterization techniques used to analyze the physicochemical properties of POSS was also carried out.

Four different binders based on calcium sulfoaluminate cements have been submitted to accelerated chlorination through ionic exchange on hydrated pastes, in order to investigate their ability to chemically bind chloride ions that might reduce chloride penetration. The composition of hydrated cements before and after the treatment was evaluated by means of an X-Ray Diffraction– 27 Al Magic Angle Spinning Nuclear Magnetic Resonance Spectroscopy combined study, allowing to take into account even partially amorphous phases and to make quantitative assumption on the relative abundance of the different aluminium-containing phases. It was found that low SO 3 Sulfoaluminate–Portland ternary systems are the most effective in binding chloride ions and the active role played by different members of the AFm family in chloride uptake was confirmed. Moreover, a peculiar behavior related to the formation of Friedel's salt in different pH conditions was also established for the different cements.

A novel solvent-free solid-state synthesis was used to prepare a non-crystalline polysilsesquioxane sample, with a peculiar viscous form. The material was synthesized through direct self-condensation of a partially condensed polyhedral oligomeric silsesquioxane (POSS) and its physico-chemical properties, in terms of composition/structure, thermal stability and hydrophobicity, were investigated.

Plasticized&ndash, Poly(vinyl chloride) (P-PVC) for cables and insulation requires performances related to outdoor, indoor and submarine contexts and reduction of noxious release of HCl-containing fumes in case of thermal degradation or fire. Introducing suitable nanomaterials in polymer-based nanocomposites can be an answer to this clue. In this work, an industry-compliant cable-grade P-PVC formulation was added with nanostructured materials belonging to the family of Polyhedral Oligomeric Silsesquioxane (POSS). The effects of the nanomaterials, alone and in synergy with HCl scavenging agents as zeolites and hydrotalcites, on the thermal stability and HCl evolution of P-PVC were deeply investigated by thermogravimetric analysis and reference ASTM methods. Moreover, hardness and mechanical properties were studied in order to highlight the effects of these additives in the perspective of final industrial uses. The data demonstrated relevant improvements in the thermal stability of the samples added with nanomaterials, already with concentrations of POSS down to 0.31 phr and interesting additive effects of POSS with zeolites and hydrotalcites for HCl release reduction without losing mechanical performances.

A novel luminescent metal-containing POSS, bearing in the structure the europium ion, was synthesized and characterized. The corner-capping reaction between the partially condensed isobutyl-POSS (molecular formula (C4H9)7Si7O9(OH)3) and the anhydrous EuCl3, under basic conditions, led to a completely condensed Eu(III)-containing POSS. The molecular compound involves THF molecules, coming from the reaction medium, in the coordination sphere on Eu(III). A deep optical characterization demonstrated that the Eu(III)-POSS sample is characterized by a quantum efficiency of ca. 14% and high photostability. Both these properties render this molecular platform an ideal candidate for the construction of luminescent devices and light-harvesting systems.

The early hydration of three cementing materials has been investigated in situ by Synchrotron X-ray Tomographic Microscopy thanks to an automatic sample exchanger recently integrated at the TOMCAT beamline at the Swiss Light Source in Villigen (CH). Hydration has been investigated by following the three dimensional evolution of pastes up to 12 h, with particular attention to the consumption of anhydrous phases, the formation of hydrates and to changes in microstructure. A lecture key for the interpretation of the tomographic images is proposed, based on the relationship between the linear attenuation coefficient μ-function of the density and elemental composition of each mineral phase- and the corresponding grey tone experimentally observed. Some examples of application of the technique are proposed, such as: a comparison among the reaction kinetics of the three investigated cements, the study of morphological evolution of mineral phases, the analyses of the three-dimensional evolution of the pore network.

Copper carboxylates were identified as degradation residues on the surface of a metallic pigment used in the illumination and in the text of a 9th century Italian manuscript containing the Homilies on the Gospels of Gregory the Great, belonging to the Archive and Chapter Library of Vercelli (Italy). These compounds are responsible of the greenish aspect that several text lines and decorated initials have developed over time from their original golden texture, starting from more than a century as could be guessed from the early 20th century descriptions of the manuscript by art historians. Further, Raman investigations carried out on a particle recovered from the gutters between folios allowed (1) the identification with good accuracy of the nature of these compounds, confirmed by scanning electron microscopy-energy dispersive X-ray (SEM-EDX) analysis, (2) proposing a hypothesis on their origin as due to the interaction of copper with carboxylic acids and (3) making suggestions on the proper restoration intervention; moreover, evidence was found for similar compounds in three 9th–10th century Italian manuscripts coming from Bobbio abbey. Besides, the presence of orpiment in ink composition was verified and compared with citations in some medieval texts. Copyright © 2010 John Wiley & Sons, Ltd.

Calcium sulfoaluminate (CSA) cement is a sulfate-based binder whose high-performance hydraulic behavior depends on the rapid formation of ettringite, when grinded clinker is hydrated in presence of gypsum. Ettringite is a calcium aluminum sulfate mineral characterized by high water content, estimated as 32 water molecules per formula unit. Three examples of utilization of near-infrared (NIR) spectroscopy are here shown. First of all, information on water distribution in pure ettringite was deduced and compared with infrared analyses. Then its thermal behavior has been followed up to 400 °C, allowing to improve the knowledge about water loss and thermal decomposition of this hydrated phase. Finally, the obtained results have been employed in order to follow hydration of CSA cement sample, demonstrating thus that NIR spectroscopy, being highly sensitive to water amount and distribution, can be an extremely useful tool for hydration studies.

The possible interactions between luminescent moieties with hydrotalcite (HTLC) host have been investigated. We present the work done in synthesizing luminescent materials containing coumarin-3-carboxylic acid (3CCA). A hydrothermal synthesis is carried out to intercalate the 3CCA into the HTLC with empirical formula: [M(II)0.65M(III)0.35 (OH)2](X)0.35 · nH20], where MII = (Zn2+), MIII = Al3+, X = 3CCA− or NO. The ZnAl HTLC materials with [M(II)/M(III) ≈ 2.0] thus synthesized were characterized by XRPD/FTIR/ICP-MS/TGA/SEM techniques and solid-state luminescent measurements. The thermal stability and the luminescent properties of obtained hybrid materials are promising because of the observed photoluminescence in the visible region and their high-temperature resistance indicated by the in situ XRPD measurements and TGA/DTG analysis.

The charge-transfer molecular complex fluorene/7,7,8,8-tetracyanoquinodimethane (TCNQ) was obtained by an unprecedented in situ solid-state direct synthesis. The reaction advancement was monitored with Raman spectroscopy and high-resolution X-ray powder diffraction (XRPD). The experiments were performed with a novel setup (SNBL, Grenoble) capable of combining both techniques simultaneously at in situ conditions. Raman spectroscopy allowed the characterization of the reaction kinetics during the initial steps at the surface of the TCNQ crystallites, when no or very little reaction is observed by the XRPD probe. From Rietveld refinement of the synchrotron XRPD data, the time evolution of the amounts of reactants and product was obtained for the reaction proceeding into the bulk of the TCNQ crystals, together with the crystal size analysis. These data were analyzed exploiting the Avrami equation to obtain rate constants, reaction orders, and activation energies. The reaction, after starting at the surface of...

X-ray powder diffraction played a key role in materials science over the past 25 years. It is now possible to employ powder diffraction at in situ conditions to study solid-state transformations. “Real” materials science samples often show deviations from the “perfectly crystalline” state and hence powder diffraction reaches its limits. Spectroscopic techniques can often provide useful complementary information. With the aim of gaining information from this aspect, we combined Raman spectroscopy with diffraction. A novel experimental setup for simultaneous in situ Raman and XRPD experiments was designed and realized at the SNBL line at ESRF Synchrotron (Grenoble-F). High-resolution XRPD data can be collected with a time resolution in the range of minutes. A permanently installed Raman spectrometer can now be used to measure the same sample at the same spot under the same conditions. A wide variety of non-ambient conditions are available. The setup is described with limitations and potentialities, by descr...

Portland clinker production consists essentially in the burning of material with defined composition in a rotary kiln at temperatures around 1450 °C. The main fuel used in this process is coal, even though in the last few years the use of alternative fuels has been increasing. Four main minerals are formed, namely, tricalcium and dicalcium silicate, tricalcium aluminate and tetracalcium aluminoferrite. Along with these main phases, variations in burning conditions of fuels or in the local composition of raw materials can lead to the formation of relatively high amounts of secondary by-products, which can negatively affect the quality of the final material. Characterization of these by-products allows not only optimization of the process of clinker production but also the design of special refractory materials for the wall of kilns and preheaters. Being found as particles included in (or alternating to) a hard solid clinker matrix, a detailed characterization of these extra phases could be achieved only via microscopic techniques. In this work, micro-Raman spectroscopy has been successfully tested as a highly selective method for characterization and localization of included minerals that formed as overlapped crusts deposited on the internal wall of a conventional rotary kiln for cement production, without any manipulation of the sample. Understanding the chronological order of deposition of these overlapped layers is extremely important, as it is the only way to go back up to the production process and to individuate the problem. Copyright © 2008 John Wiley & Sons, Ltd.

In this work we propose a methodology showing how plasma fluorinated single-walled carbon nanotubes (SWNTs) reacted with a primary aliphatic amine (i.e. butylamine, BAM) hardener (BAM-SWNTs) can be used for preparing an integrated nanotube composite material. The results show that BAM-SWNTs act as a strong catalyst with the emergence of specific interactions of cross-linking between the epoxy and amino-functionalized SWNTs during the cure reaction as confirmed by Raman spectroscopy, thermal and dynamic mechanical analysis. Scanning electronic microscopy images showed that the amino functionalized nanotubes have a better dispersion in the polymer matrix. Moreover, the obtained nanocomposites present an improvement in mechanical strength with respect to those prepared with un-functionalized SWNTs.

Synthetic saponite-like materials were prepared by traditional hydrothermal crystallisation at 513 K of 1 SiO 2 ; 0.835MgO; 0.056Al 2 O 3 ; 0.056Na 2 O; nH 2 O gel with variable amount of H 2 O. The obtained layered materials were submitted to a systematic study of textural properties, morphology, thermal behaviour of the produced materials by combining different experimental techniques (XRD, SEM, TEM, N 2 physisorption, Solid State MAS NMR). For the first time, a fine characterisation of the surface acidity of the produced saponites performed by FTIR spectroscopy of CO probe molecule (complemented with NH 3 ) was given. The dilution (H 2 O/Si ratio) of the synthesis gel played a significant role in determining the physico–chemical properties of the final products, the higher the gel dilution, the smaller the platelets determined by TEM analysis. Moreover, specific surface area of saponite samples increased with decreasing the lamellae dimensions. NLDFT and BJH approaches applied to nitrogen adsorption and desorption branches were used to define the porosity of the samples. Both micro- and mesopores were found, the latter being much more abundant on the saponite prepared at the highest gel dilution (SAP50, H 2 O/Si = 50). A combined XRD and IR study performed at variable temperature showed that the materials were stable up to 773 K and that thermal stability is not dependent on the dilution of the synthesis gel. 27 Al-MAS NMR indicated that SAP50 sample contained a higher concentration of octahedral Al species than SAP20 (H 2 O/Si = 20). These species were mainly located in the octahedral sheets as a result of isomorphous substitution of Al III with Mg II ions, and this consequently reduced the cation exchange capacity (CEC) of the material. FTIR of CO adsorption was used to monitor, beside surface protons, interlayer cations. Both magnesium and sodium ions were found in the interlayer space, and their distribution varied from one sample to another. Magnesium, for instance, was more abundant in SAP50 than SAP20. Protons located on bridged hydroxyls [Si–O(H)–Al] of the tetrahedral silica sheets displayed acidity similar to the most acid H-ZSM-5 zeolites.

A catalyst-free innovative synthesis, by combined X-ray chemical vapour deposition and low-temperature thermal treatments, which has not been applied since so far to the growth of germanium nanowires (Ge-NWs), produced high yields of the nanoproducts with the GeH4 reactant gas. Nanowires were grown on both surfaces of a conventional deposition quartz substrate. They were featured with high purity and very large aspect ratios (ranging from 100 to 500). Products were characterized by scanning electron microscopy with energy-dispersive atomic X-ray fluorescence and transmission electron microscopies, X-ray powder diffraction diffractometry, thermogravimetric analysis with differential scanning calorimetry, vibrational infrared and Raman and ultraviolet–visible–near infrared spectroscopies. A quantitative nanowire bundles formation was observed in the lower surface of the quartz substrate positioned over a heating support, whilst spots of nanoflowers constituted by Ge-NWs emerged from a bulk amorphous germanium film matter, deposited on the upper surface of the substrate. The nanoproducts were characterized by crystalline core morphology, providing semiconductive features and optical band gap of about 0.67 eV. The possible interpretative base-growth mechanisms of the nanowires, stimulated by the concomitant application of radiant and thermal conditions with no specific added metal catalyst, are hereafter investigated and presented.

The synthesis of oxidised water-soluble fullerenes, prepared by chemically-induced aerobic oxidation, yields functionalised carbon cluster structures, which are oxidised by the covalent insertion of different oxygen units. Their strictly pH-dependent behaviour in aqueous solutions appears to be properly ascribed to the existence of directly attached carboxylic moieties. The presence of these groups, which are usually neglected and underestimated, has been thoroughly investigated. Several concurrent spectral (UV–VIS, XPS, solid-state 13C CPMAS NMR, FT-IR, Raman, EDAX, TGA-MS, ESI-MS) and chemical (acid–base behaviour, salt precipitation by metal-complexation, carboxylic functionalisation) methods have provided a definitive set of consistent evidence, indicating for the first time the direct linkage of carboxylic groups on water-soluble fullerenes prepared in this manner.

Materials containing disordered moieties and/or amorphous or liquid-like phases or showing surface- or defect-related phenomena constitute a problem with respect to their characterization using X-ray powder diffraction (XRPD), and in many cases Raman spectroscopy can provide useful complementary information. A novel experimental setup has been designed and realized for simultaneousin situRaman/high-resolution XRPD experiments, to take full advantage of the complementarities of the two techniques in investigating solid-state transformations under non-ambient conditions. The added value of the proposed experiment is the perfect synchronization of the two probes with the reaction coordinate and the elimination of possible bias caused by different sample holders and conditioning modes used in `in situbut separate' approaches. The setup was tested on three solid-state transformations: (i) the kinetics of the fluorene–TCNQ solid-state synthesis, (ii) the thermal swelling and degradation of stearate–hydrotalcite, and (iii) the photoinduced (2 + 2)-cyclization of (E)-furylidenoxindole. These experiments demonstrated that, even though the simultaneous Raman/XRPD experiment is more challenging than separate procedures, high-resolution XRPD and Raman data can be collected. A gas blower allows studies from room temperature to 700 K, and 100 K can be reached using a nitrogen cryostream. The flexibility of the experimental setup allows the addition of ancillary devices, such as a UV lamp used to study photoreactivity.

In this experimental study, waste particulate of domestic flame combustion of wooden matters have been reacted according to a direct mild-condition reductive-oxidative chemical synthesis. Water-soluble graphenic and polycyclic aromatic frameworks have been extracted from graphitized carbon residues. Products have been recovered by elemental carbon contented in both fly and bottom combustion particulate. Their pH-sensitive behavior in aqueous solutions has been elucidated. Products and reactant substrates have been spectroscopically characterized by mean of solid state vibrational FT-IR and Raman, UV-VIS, XRD, solution 1H and 13C NMR, SEM-EDX and MALDI-TOF MS techniques. Discussion upon the reactivity of flame carbon residues of wooden matters is reported, in comparison to the reactivity displayed by other graphenic structures, according to the reported synthetic protocol.

A wide series of carbon nanostructures (ranging from fullerenes, through carbon nanotubes, up to carbon nanofibers) promise to change several fields in material science, but a real industrial implementation depends on their availability at reasonable prices with affordable and reproducible degrees of purity. In this study we propose simple instrumental approaches to efficiently characterize different commercial samples, particularly for qualitative evaluation of impurities, the discrimination of their respective spectral features and, when possible, for quantitative determination. We critically discuss information that researchers in the field of nanocomposite technology can achieve in this aim by spectral techniques such as Raman and FT-IR spectroscopy, thermo-gravimetrical analysis, mass spectrometry–hyphenated thermogravimetry, X-ray diffraction and energy dispersive spectroscopy. All these can be helpful, in applied research on material science, for a fast reliable monitoring of the actual purity of carbon products in both commercial and laboratory-produced samples as well as in composite materials.

Co2(CO)8 has been reacted with but-2-yn-1,4-diol (BUD) and the reactivity of the resulting complex Co2(CO)6(HOCH2C≡CCH2OH) (complex 1) is discussed. Complex 1 has been reacted with all the components used in the synthesis of sol-gel materials based on tetraethyl-orthosilicate (TEOS) with the aim at obtaining evidences for the processes occurring during the formation of inorganic-organometallic sol-gel materials containing BUD. Reaction pathways are discussed.

An innovative process for a mass production of multi-wall carbon nanotubes (MWCNTs) by means of pyrolysis of virgin or recycled polyolefins is described. The technique uses solid-gas fluidised bed reactors, continuously operated under conditions which allow high heating rates of the polymers, high heat and material exchange coefficients and a reliable control of residence times in the reactor. The obtained MWCNTs have been characterized by TGA, SEM and TEM microscopy as well as X-ray diffractometry and Raman spectroscopy. The results demonstrate that the proposed process allows the production of MWCNTs compatible with most of the already known applications, in large quantities and at low cost. This makes extremely wider the field of possible applications of these nanostructured materials. © 2005 Elsevier Ltd. All rights reserved.

The mechanism of thermal degradation of several substituted polyhedral oligomeric silsesquioxanes (POSS) cages is studied in this work. Hydrogen POSS and methyl POSS shows incomplete sublimation on heating, both in inert atmosphere and in air. Isobutyl and octyl substituted POSS undergo an almost complete evaporation when heated in inert atmosphere. In air, oxidation competes with volatilization, producing a considerable amount of silica-like residue on heating up to 800 °C. Phenyl POSS shows a higher thermal stability than saturated aliphatic POSS and limited volatility, producing a ceramic residue at high yield on heating in nitrogen, composed of a silica containing a considerable amount of free-carbon. A lower amount of residue is shown after heating in air, corresponding to the POSS Si–O fraction. A vinyl POSS cage/network resin is also studied, in comparison to above materials, showing the highest ceramic yield.

Three solid molecular complexes of fluorene with electron-withdrawing tetracyanoethylene, 1,2,4,5-tetracyanobenzene and 7,7,8,8-tetracyanoquinodimethane were synthesized. Single-crystal X-ray diffraction data elucidated the order–disorder aspects of the crystal structures ascribed to the different molecular symmetries of the employed building blocks. This hypothesis was confirmed by the structural and energetic results of ab initio periodic calculations. Donor–acceptor solid state interactions between molecular counterparts have been highlighted by electron and vibrational IR and Raman solid state spectroscopy, indicating a significant extent of electron density transfer from the fluorene unit towards the cyano-molecules. The experimental evidences of donor–acceptor interactions between molecular counterparts were compared to the lattice energies and solid state band-gaps, obtained by periodic calculations, and to the cluster HOMO–LUMO differences, obtained by isolated cluster calculations. A good agreement between spectral and theoretical data was found.