Fiberglass/thermoset matrix composite present important properties, such as specific mass and mechanical strength, aiming to replace some engineering materials. However, its mixture of different materials transforms them into an environmental problem, due to the complex recycling process. The highlight is meeting the demands of environmental pressures and for establishing recycling mechanisms, the proposal is to study physical recycling processes, focusing on the microwave-assisted pyrolysis process and also recovering fiberglass. The results were: humidity around 3 wt. %; the average loss of mass around 68 wt. %; the tensile strength is reduced by about 76 % when a composite with recycled fiberglass is laminated, as compared to the use of virgin fiberglass. This work establishing the physical recycling mechanism and route for composite materials, identifying the thermal degradation processes, for thus applying them to other materials, still considered environmental issues, technically and economically making these materials manufacturing processes viable, as well as establishing a recycling route.

Researches about nanomaterials related to properties such as superhydrophobicity, self-cleaning, corrosion and scratching resistance can be directly related to the materials’ wettability. This characteristic is quantified by the contact angle made between the surface and a water droplet, in which angles above 90 degrees are considered to be hydrophobic and those above 150 degrees, superhydrophobic. The focus of this work was the development of a superhydrophobic self-cleaning surface, using silica nanoparticles with a particle diameter around 400 nm to 800 nm (produced via sol-gel, referring to the classic Stöber method) functionalized with perfluorooctyltriethoxysilane (POTS) on a polymeric substrate polymethyl methacrylate (PMMA). Four different surface treatment conditions were analyzed: untreated, treated with non-functionalized silica nanoparticles, treated only with POTS and treated with silica nanoparticles functionalized with POTS. For this last condition, a static water contact angle of (150.0 ± 0.44) degrees and a dynamic water contact angle of (7.5 ± 0.38) degrees were obtained, which is a typical value of a superhydrophobic surface. However, the surface treated with POTS alone had a contact angle of 115 degrees. The high contact angle value was due to the low surface energy obtained, which was of (1.45 ± 0.02) dyn/cm. The modified superhydrophobic surface revealed a superior self-cleaning performance by freely rolling spherical water drops on the non-wettable solid surface. The stability of the modified surface has been proven by water jet impact.

Abstract Global generation of waste electrical and electronic equipment (WEEE) is increasing quickly. Metals from WEEE can be recovered by using unit operations of chemical engineering. This paper describes a combined hydrometallurgical route (sulfuric oxidant leaching + solvent extraction) to recover copper from printed circuit boards (PCBs). A non-magnetic fraction from comminuted PCBs was used to perform leaching tests at 75ºC for 6 hours in an oxidizing media (sulfuric acid + hydrogen peroxide). In order to separate zinc, aluminum, and copper from the leaching liquor, solvent extraction tests were carried out using D2EHPA. Parameters that influence the process, such as pH, extractant concentration, and the aqueous/organic (A/O) ratio were investigated. Solvent extraction experiments were carried out in two stages: i) separation of zinc, aluminum, and residual iron, and ii) copper separation. The results showed that the leaching obtained around 60% aluminum, 94% copper, 76% zinc, 50% nickel and residual iron from the non-magnetic fraction of PCBs. With the solvent experiments, in the first stage, 100 wt.% zinc, iron and aluminum were extracted at pH 3.5, 2:1 A/O, 10 % (v/v) D2EHPA, while, in the second stage 100% of the copper was extracted at pH 3.5, 1:1 A/O, 20 % (v/v) D2EHPA.