Publications by authors named "Laura H de Carvalho"

The aim of this work is to analyze the effect of water absorption on the mechanical properties and damage mechanisms of polyester/glass fiber/jute fiber hybrid composites obtained using the compression molding and vacuum-assisted resin transfer molding (VARTM) techniques with different stacking sequences. For this purpose, the mechanical behavior under tensile stress of the samples was evaluated before and after hygrothermal aging at different temperatures: TA, 50 °C, and 70 °C for a period of 696 h. The damage mechanism after the mechanical tests was evaluated using SEM analysis.

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The development of polymeric biocomposites containing natural fibers has grown over the years due to the properties achieved and its eco-friendly nature. Thus, biocomposites involving a polymer from a renewable source (Biopolyethylene (BioPE)) and babassu fibers (BFs), compatibilized with polyethylene grafted with maleic anhydride (MA) and acrylic acid (AA) (PE-g-MA and PE-g-AA, respectively) were obtained using melt mixing and injection molded into tensile, impact, and HDT specimens. Babassu fiber was characterized with Fourier transform infrared spectroscopy (FTIR), thermogravimetry (TGA), and scanning electron microscopy (SEM).

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Active packaging made from biodegradable polymers and natural additives appears as an ecological alternative. In addition to having antioxidant activity and enhancing food preservation, it allows mitigating the negative impacts caused by improper disposal. This study pursued to produce biodegradable films based on a polymer blend PBAT/PLA (Ecovio®) using the flat extrusion method.

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The aim of this work was to produce filaments of PLA/PBAT and NPK fertilizer adsorbed on organophilized bentonite intended for application in the prototyping of biodegradable agricultural artifacts in 3D printing, using the Fused Deposition Modeling (FDM) technique. This is the first time that we have reported this composite for a 3D printing approach. Systems containing PLA/PBAT, organobentonite and NPK were initially processed in an internal mixer and later extruded as filaments in a single-screw extruder.

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This work presents an experimental study related to the mechanical performance of a special design spring fabricated with a superelastic shape memory alloy (SMA-SE). For the experimental testing, the spring was coupled in a rotor machine, aiming to attenuate the mechanical vibration when the system went through a natural frequency without any external power source. It was verified that the reduction in instabilities stemmed from the better distribution of vibration force in the proposed device, as well as the damping capacity of the spring material.

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Blending of biodegradable polymers in combination with low-price organic fillers has proven to be a suitable approach to produce cost-effective composites in order to address pollution issues and develop products with superior mechanical properties. In the present research work PBAT/PHB/Babassu composites with 25, 50, and 75% of each polymer and 20% of Babassu were produced by melting extrusion. Their thermal, mechanical, and morphological behavior was investigated by differential scanning calorimetry (DSC), tensile testing, and scanning electron microscopy (SEM).

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