Innovative thermal and acoustic insulation foam by using recycled ceramic shell and expandable styrofoam (EPS) wastes.

Ceramic foams were produced using ceramic shell (mullite source), an industrial solid waste from the precision casting process, and expandable styrofoams, EPS (d50 < 1 mm) as pore former, envisaging thermal and acoustic insulation applications. Physical, chemical, structural properties of the selected raw materials (wastes) were characterized. The influence of the amount and morphology of the EPS powder beads on the microstructure, thermal conductivity, acoustic absorption and compressive strength of ceramic shell foams were evaluated. Batches containing well mixed ceramic shell powder (d50 < 2 µm), EPS beads, in different proportions (from 10 to 70 vol%), were added as pore forming agent, and BonderPlus® (Na2SiO3 solution) were uniaxially pressed at 20 MPa, dried and fired in controlled conditions. The experimental results showed that homogeneous microstructures of elongated and interconnected pores with sizes between 115 and 1200 µm can be obtained. These connections exhibit a significant impact on the thermal/sound absorption properties, as a consequence of the interaction between air molecules within the pores through the passage of the thermal/sound wave. Ceramic shell foams (containing 70 vol% of EPS powder beads) featured porosities up to 77%, thermal conductivity of 0.061 W/mK, sound absorption coefficient of ∼0.9 (3 kHz), and excellent compressive strength ∼5.4 MPa. In addition, the use of ceramic shells wastes for the manufacture of acoustic and thermal insulators with suitable microstructural characteristics is a great sustainable opportunity, since with the use of this refractory waste, is possible to avoid the release to the atmosphere of about 3.1 kg of CO2 per kg of manufactured material.

Bentonite-based organoclays as innovative flame retardants agents for SBS copolymer.

Two organophilic bentonites, based on nitrogen-containing compounds, have been synthesised via ion exchange starting from pristine bentonite with octadecyltrimethylammonium bromide (OTAB) and with synthetic melamine-derived N2,N4-dihexadecyl-1,3,5-triazine-2,4,6-triamine (DEDMEL). The chemical and morphological characterization of the organoclays was based on XRD, TEM, Laser Granulometry, X-Ray Fluorescence and CEC capacity. Copoly(styrene-butadiene-styrene)-nanocomposites (SBS-nanocomposites) were obtained by intercalation of the SBS-copolymer into these new organoclays by melt intercalation method. XRD and TEM analysis of the organoclays and of the micro/nano-composites obtained are presented. The effect of the organoclays on the SBS-nanocomposite's flammability properties was investigated using cone calorimeter. An encouraging decrease of 20% in the peak heat released rate (PHRR) has been obtained confirming the important role of melamine's based skeleton and its derived organoclays to act as effective fire retardants and for the improvement of this important functional property in SBS copolymers.