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Polyethylene-montmorillonite nanocomposites were prepared in the melt applying various ultrasonic powers (231, 347, and 462 W) and temperatures (185, 200, and 215 8C) in the presence of itaconic acid. Dispersion-exfoliation of montmorillonite and in situ low density polyethylene functionalization with itaconic acid were carried out by ultrasound assisted extrusion process. Clay dispersion and exfoliation was evaluated by X-ray diffraction (XRD) and electronic microscopy (STEM). The degree of grafting itaconic acid into low density polyethylene (LDPE) was determined by infrared analysis (FTIR) and titration technics. Ultrasoundtreated nanocomposites showed improved clay dispersion compared with non-treated ones. Mechanical properties, XRD, and STEM microscopy indicated that the grafting level, clay dispersion, and exfoliation was directly influenced by IA concentration, temperature, and ultrasonic energy. For instance, the itaconic acid grafted into LDPE was improved from 0.13% to 0.71% when ultrasound power was increased and when temperature was reduced. The modulus was enhanced up to 225 MPa when the ultrasound power was increased up to 462 W. The nanocomposites decomposition temperature, determined by thermogravimetric analysis, was increased nearly 20 8C when 1% w/w itaconic acid was used.

Thermal conductivity of epoxy resins was highly improved (up to 1.95 W/mK) with the addition of 7, 10, and 15 wt% of a hybrid filler composed of 70-30 wt % ratio of graphene and copper nanoparticles, respectively. Hybrid filler was obtained by high energy mechanical milling in two manners; just the two nanoparticles "dry milling" and with the addition of ethylene-glycol "wet milling." The crystalline structure was severely destroyed with dry milling but not with wet milling. Wet milling was thereafter used to obtain the hybrid filler that was later used in producing the epoxy nanocomposites. Raman spectrometry, X-ray diffraction, X-ray photoelectron spectroscopy (XPS), and electron microscopy were used to determine the interaction between both nanoparticles in the obtained hybrid graphene-copper filler. XPS findings suggest that certain amount of copper is bonded to the graphene surface nanoparticles. This bonding could be carried out by the charge-transfer interaction between graphene and copper or by physisorption of copper between the graphene nanosheets. The signals in 119.2 and 120.7 eV, observed in the deconvolution of Cu3s signal, correspond to copper carbon bonds Cu═C and Cu C, respectively. This "wet" mechanical milling methodology represents a good option to prepare graphene/metal (hybrid) fillers.

In the construction industry, the large number of residues presents a challenge for recycling and the possibility of producing new materials. This study reported the effects of the addition of polyvinyl chloride (PVC) residues and cement/alumina trihydrate on the production of a fire-resistant thermalacoustic insulation material. The composites were verified by scanning electron microscopy, the polyurethane (PU) cells were maintained with the addition of PVC, cement, and trihydrate alumina. The reduction in compressive strength for boards with 50% PVC waste as a replacement for the PU raw material. The boards showed the composites' conductivity coefficient was lower than that of the perforated brick and combustion deceleration up to flame extinction in the flammability test (UL94) because of the PVC/cement/ alumina trihydrate. They also presented cost savings (~57%) and carbon dioxide emissions (~49%) from the raw material, contributing to developing a less predatory and socio-environmentally responsible industry.

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