Sintesi di Geopolimeri con scarti industriali, Caratterizzazione Chimica e Microstrutturale

Ricerca di nuove tecniche per lo sviluppo di nuovi materiali da costruzione rinnovabili e non inquinanti, attraverso l'utilizzo di rifiuti/sottoprodotti organici e inorganici. Individuazione di materie prime naturali e di recupero, ingegneria di prodotto e di processo, caratterizzazione del prodotto con particolare attenzione all'impatto ambientale.Research of new techniques for the development of new renewable and non-polluting building materials, through the use of organic and inorganic waste/by-product. Identification of natural and recovery raw materials, product and process engineering, product characterization with particular emphasis on the environmental impact

Cork powdery industrial waste in metakaolin–geopolymer matrix

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Acid attacks on metakaolin based-geopolymers with recycled corundum: A study focused on the role of anions by NMR characterization

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Efficient Addition of Waste Glass in MK-Based Geopolymers: Microstructure, Antibacterial and Cytotoxicity Investigation

Reuse of waste glass can significantly decrease the quantity of waste to be treated or disposed of in landfills, allowing to both diminish the ecological damage and to reduce the costs of transportation for removal. Geopolymer mixes with diverse percentages (20, 50 and 60 wt%) and with different grain size ranges (37 µm < diam < 53 µm; 75 µm < diam < 105 µm) of waste glass and the residual part of pure metakaolin were prepared by addition of NaOH and sodium silicate as alkaline activator solutions. The effect of waste glass on the mechanical and microstructure of new geopolymers has been explored in this study. Fourier transform infrared spectroscopy (FTIR) evidenced the reactivity of waste glass in terms of Si–O and Si–O–Al bonds, more evident for the finer waste glass powder. The consolidation of the materials has been established by reduced weight loss in water and decreased pH and ionic conductivity of the eluate after 7, 14 and 28 days of curing at room temperature. The decrease of the mechanical properties with waste glass content was less evident for the finer glassy powders, yet the value of about 4-5 MPa indicates their potential use as non-structural materials. The consolidated final materials were tested for their effects on the microbial growth of Escherichia coli and Enterococcus faecalis after 24 and 48 h, respectively. The samples showed a very limited and absent inhibition zone, for fine and coarse grain size ranges, respectively. Finally, the cytotoxicity tests accomplished the ecological valuation of the final consolidated products

Waste Cork in Metakaolin–Geopolymer Matrix: Physico-Mechanical Characterization

Cork powdery waste (CW) from agglomerated cork caps manufacturing is commonly transported to waste-to-energy plants, although it could be locally exploited for lightweight building materials. The transformation of CW into a geopolymer formulation to obtain a novel composite formulation suitable for insulating panels is presented in this contribution. The geopolymer mix was based on metakaolin added to NaOH and Na silicate solutions, to which 2.4, 4.8 and 9.1 wt% (calculated upon dry metakaolin) of CW in the form of as-received powdery waste were added. No pre-treatments were performed on CW and no thermal curing was conducted for the alkaliactivated product that was consolidated at room temperature to improve product sustainability. The insulating panel presented an apparent density of about 1.521 to 0.990 ± 0.001 g/cm3 , combined with a total porosity in the range of 35.61 to 56.22 ± 0.003 % for 2.4 to 9.1 wt% of CW, respectively, and this was dependent upon ageing time. The values of its mechanical properties (compressive strength ranged from 2.5 to 1.5 MPa at 28 and 90 days of curing time, complying with UNI EN 998-2) and thermal insulating properties (thermal conductivity around 0.1146 W/mK) indicated that the highest percentage of CW in the formulations, i.e., 9.1 wt%, was suitable to obtain self-standing insulating panels

Polyetherimide(PEI)/SiO2 organic/inorganic composite: sol-gel synthesis, structural characterization, surface interactions

Polyetherimide (PEI), an amorphous thermoplastic material is a promising candidate for wide applications due to its high heat stability and its biocompatibility in human tissue. In the present paper, PEI (4 wt%) was added to SiO2 inorganic matrix in order to obtain a novel composite biomaterial through sol-gel route. Structural characterization of the biomaterial was provided by Fourier transform infrared spectroscopy (FTIR) that confirmed the presence of both organic and inorganic components in the structure. A theoretical study based on Molecular Mechanics and Molecular Dynamics methods will be useful in order to better understand the intermolecular interaction at the organic/inorganic interface compared with the discussed structural characterization. Concerning the compatibility in the biological system, a study of antibacterial properties was carried out. The effect of PEI/SiO2 composite on gram-negative bacterium Escherichia coli, was analyzed with a marked antimicrobial activity

Recycling of Waste Corundum Abrasive Powder in Mk-Based Geopolymers

Recycling corundum abrasive powder in metakaolin-based geopolymer formulations is proposed to reduce the amount of waste to be treated or disposed of in landfills, allowing to decrease ecological damage as well as to reduce transport costs for removal. The addition of waste corundum, as an important source of Al(2)O(3), has proved to increase the slight ionic conductivity of the leachate solution obtained after immersion in water of samples at 28 d of curing at room temperature. With the same curing conditions, the geopolymerization process has not been disturbed as evidenced by the FT-IR peak shift and XRD patterns. It was recorded a decrease in resistance to compression of the consolidated geopolymers of about 5% with 10 wt% addition and of about 77% with the addition of 20 wt% of waste corundum. In any case, the waste abrasive powder does not release heavy metals when added to a geopolymeric formulation based on MK, NaOH, and Na-silicate, and does not show relevant antibacterial properties, indicating the formation of a stable and safe final product with a ceramic-like appearance

Wear resistant nanocomposites based on biomedical grade UHMWPE paraffin oil and carbon nano-filler: Preliminary biocompatibility and antibacterial activity investigation

Abstract: In the present paper, we investigate the effectiveness of nanocomposites (composed of ultra-high molecular weight polyethylene (UHMWPE) mixed with carbon nano-filler (CNF) and medical grade paraffin oil (PO), from the biological point of view. Wear measurements were carried out without (air) and with lubricant (distilled water, natural, and artificial lubricant), and antibacterial activity and cytotoxicity were evaluated. The results highlighted that the presence of CNF is important in the nanocomposite formulation because it reduces the wear rate and prevents oxidative degradation during its processing. An amount of 1.0 wt % of CNF is best because it reaches the optimal distribution within the polymeric matrix, resulting in the best wear resistant, bio-active, and anti-bacterial nanocomposite among all investigated sample

Characterization of white metakaolin-based geo-polymers doped with synthetic organic dyes

Over the years, many materials have been used to restore buildings, paintings, ceramics, and mosaic pieces exhibiting different types of dyes and colour hues. Recently, geopolymers have been used for restoration purposes owing to their high chemical and mechanical resistance. In this work, white metakaolin was used to obtain white geopolymers, cured at 25 and 40 °C, as bulk materials to be coloured with synthetic organic dyes, i.e., bromothymol blue, cresol red, phenolphthalein, and methyl orange. These dyes were added during the fresh paste preparation to obtain dyed geopolymeric solids. Ionic conductivity and pH measurement confirmed the chemical stability of the consolidated materials, while FT-IR analyses were used to follow the geopolymerisation occurrences at different ageing times (from 7 to 56 days). Finally, the colour hues and properties were assessed in the CIELAB colour space before and after immersion in water