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Thermal and mechanical properties of PLA-based multiscale cellulosic biocomposites

MIGUEL ANGEL RUZ CRUZ Pedro Jesús Herrera Franco Emmanuel Alejandro Flores Johnson MARIA VERONICA MORENO CHULIM LUCIANO MIGUEL GALERA MANZANO Alex Valadez González (2022, [Artículo])

In this work polylactic acid (PLA) based multiscale cellulosic biocomposites were prepared with the aim to evaluate the effect of the incorporation of cellulose nanocrystals (CNCs) on the PLA biocomposites reinforced with cellulose microfibers (MFCs). For this, PLA composite materials reinforced with both MFCs and with a combination of MFCs and CNCs were prepared, while keeping the content of cellulosic reinforcements constant. The thermal and mechanical properties of these multiscale PLA biocomposites were characterized by thermogravimetry (TGA), differential scanning calorimetry (DSC), flexural mechanical and, dynamic mechanical (DMA) tests. Likewise, they were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The results show that the replacement of MFCs by CNCs in the 1–5% range appreciably modifies the thermal and mechanical properties of multiscale compounds. For example, they increase the thermal stability of the materials, modify the PLA crystallization process and play the role of adhesion promoters since the mechanical properties in flexure increase in the order of 40% and the storage modulus increases in the order of 35% at room temperature. Also, the addition of CNCs increases the relaxation temperature of the material from 50 to 60 °C, thereby expanding the temperature range for its use. © 2022 The Author(s)

MULTISCALE BIOCOMPOSITES CELLULOSE MICROFIBER CELLULOSE NANOCRYSTALS HIERARCHICAL STRUCTURE PROPERTIES INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS TECNOLOGÍA DE MATERIALES PROPIEDADES DE LOS MATERIALES PROPIEDADES DE LOS MATERIALES

Regional analysis of the wage discrimination in the indigenous workers in Mexico

Christian De la Luz-Tovar SIBYL ITALIA PINEDA SALAZAR (2023, [Artículo, Artículo])

The objective of this research is to estimate and decompose the wage gap between indigenous and non-indigenous workers by region in Mexico, to examine whether there are regional differences in the existing wage inequality that a priori affects the indigenous population and whether these differences can be attributed to the job profile of this group or by systematic labor discrimination against them. Using the data from the 2018 National Household Expenditure Revenue Survey (ENIGH-N) and the Oaxaca-Blinder decomposition, it was found that indigenous workers face a wage gap in all regions of the county. But, this gap is more pronounced in the center and south regions, where, on average, the associated component with labor discrimination has a percentage greater than 56. In contrast, in the north-central and northern regions of Mexico, the residual component is on average less than 33%, which suggests that the wage gap is explained by differences in productivity between groups.                         

Labor economics Ethnicity wage gap Indigenous population Regions Oaxaca-Blinder decomposition Economía laboral Brecha salarial étnica Población indígena Regiones Descomposición de Oaxaca-Blinder CIENCIAS SOCIALES CIENCIAS SOCIALES