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Cashew nutshells from the northern region of Colombia were prepared to assess their potential use as a filler in polymer matrix filaments for 3D printing. After drying and grinding processes, cashew nutshells were characterized using scanning electron microscopy (SEM), attenuated total reflectance Fourier-transform infrared (ATR-FTIR), and thermogravimetric analyses (TGA). Three different filaments were fabricated from polylactic acid pellets and cashew nutshell particles at 0.5, 1.0, and 2.0 weight percentages using a single-screw extruder. Subsequently, single-filament tensile tests were carried out on them. SEM images showed rough and porous particles composed of an arrangement of cellulose microfibrils embedded in a hemicellulose and lignin matrix, the typical microstructure reported for natural fibers. These characteristics observed in the particles are favorable for improving filler–matrix adhesion in polymer matrix composites. In addition, their low density of 0.337 g/cm3 makes them attractive for lightweight applications. ATR-FTIR spectra exhibited specific functional groups attributed to hemicellulose, cellulose, and lignin, as well as a possible transformation to crystalline cellulose during drying treatment. According to TGA analyses, the thermal stability of cashew nutshell particles is around 320 °C. The three polylactic acid–cashew nutshell particle filaments prepared in this work showed higher tensile strength and elongation at break when compared to polylactic acid filament. The characteristics displayed by these cashew nutshell particles make them a promising filler for 3D printing filaments. [ABSTRACT FROM AUTHOR]

This project consists of making T-connections from Kunth guadua angustifolia joints, focusing the research on determining their behavior under tensile stresses, changing the injection with mortar as proposed by NSR-10-chapter G-12, for a mixture of RPET (recycled polyethylene terephthalate) and PS (polystyrene) plastic material. This study is proposed to the extent that guadua as an engineering material is used in different types of construction for homes, bridges, support structures, among others. However, in Colombia the available research and information about the admissible tensile strength offered by this element for structural purposes can be considered deficient compared to the benefits offered by said material. Therefore, an investigation is developed with a quantitative approach of an experimental type, in which a dosage of model mixtures for the injection polymeric matrix was carried out; specimens from the department of Norte de Santander were taken; and the tensile stress tests were carried out on the samples, for which acting tensile strengths (ft) between 1.74 MPa and 3.20 MPa were reached, which compared to the modified allowable tensile stress (F't) that under coefficients of Modification of load duration and temperature yielded a value of 16.20 MPa; which indicates a positive result given that the criterion that ft ≤ F't set forth in Regulation NSR-10, chapter G-12 Structures in Guadua is met. [ABSTRACT FROM AUTHOR]