In the present study, poly (ethylene terephthalate)-based composites were produced and characterized. These composites were composed by poly (ethylene terephthalate) (PET) reinforced with geopolymer concrete waste (GCW). Both untreated (U-GCW) and treated with oleic acid (OA) geopolymer concrete waste (T-GCW) were used in the production of the composites. The PET/GCW ratios used for either treated or untreated GCW bodies were 80/20 (wt%), 60/40 (wt%) and 50/50 (wt%). Chemical compositions were assessed by X-ray fluorescence spectroscopy (XRF), crystallinity by differential scanning calorimetry (DSC), thermal stability by thermogravimetry (TGA), microstructure by field emission gun scanning electron microscopy (FEG-SEM) with energy dispersive X-ray spectroscopy (EDS), and mechanical properties were assessed by compression tests. Fourier transform infrared spectroscopy (FT-IR) was used to check the efficiency of the treatment with OA, as well as the interaction between PET and GCW. The T-GCW PET composites showed better thermal, physical, and mechanical properties, for non-structural applications, when compared to U-GCW.

In this study, polymeric nanocomposites based on poly(methyl methacrylate) (PMMA) and silicon carbide (SiC) nanoparticles were prepared by radical mass polymerization in the presence of filler. Nanoparticles of SiC with and without surface treatment with organosilane were obtained .The nanocomposites were characterized by X-ray fluorescence (XRF), infrared spectroscopy (FTIR), thermogravimetry (TGA) and Field Emission Gun Scanning Electron Microscopy (FEG SEM) with an energy dispersive x-ray spectroscopy (EDS) detector. The produced nanocomposites showed welldispersed SiC incorporation in the PMMA matrix. The results pointed that the surface treatment on SiC fillers was successful on enhancing the interaction between the organic matrix and the inorganic filler.

The growing interest in natural lignocellulosic fibers (NLFs) is associated not only with environmental benefits but also with technical, economical and social advantages. Among the NLFs, the coir fiber and pineapple leaf fiber (PALF) are low-cost and widely available waste materials. The present work investigated the dynamic mechanical properties, by means of DMA tests, of these two different fibers as reinforcement of epoxy matrix composites. The influence on DMA properties of composites by the volume fraction and the configuration form, mat or aligned coir fiber, were also evaluated. The results showed higher E' and E" moduli values and an increase in T g with the incorporation of PALF in epoxy matrix, which indicate a superior dynamic mechanical properties for this composite in comparison to the neat epoxy resin. The experimental data also revealed a stronger interfacial interaction of PALF/ epoxy when compared to coir fiber/epoxy. It was also found a lower tan δ value exhibited by higher volume fractions of aligned coir fibers in epoxy matrix.

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Martensitic transformation can be induced by plastic deformation in metastable iron-based alloys, such as stainless steels containing limited amounts of C, Ni and Cr. This transformation takes place at the temperature range from M s and M d , usually at relatively lower temperature values. The transformed martensite has been associated with maximum ultimate strength and relatively high ductility. In the present work, the tensile fracture characteristics of a metastable AISI type 302 stainless steel was investigated in the range of temperatures from -196°C to 25°C. Mechanical properties were compared to those of a stable AISI type 310 austenitic stainless steel. It was found that in 302 steel, its high degree of metastability and dilute dispersion of inclusions result in higher strength and complex modes of fracture, one of which consisting of martensite surrounding globular inclusions.