Polylactic acid (PLA)-based nanocomposites were prepared by twin-screw extrusion. Graphene oxide (GO) and an ionic liquid (IL) were used as additives separately and simultaneously. The characterization of the samples was carried out by means of Fourier transform infrared (FT-IR) and Raman spectroscopies, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The viscoelastic behavior was determined using dynamic mechanical analysis (DMA) and rheological measurements. IL acted as internal lubricant increasing the mobility of PLA chains in the solid and rubbery states; however, the effect was less dominant when the composites were melted. When GO and IL were included, the viscosity of the nanocomposites at high temperatures presented a quasi-Newtonian behavior and, therefore, the processability of PLA was highly improved.

The main purpose of the present study is to improve the tribological performance of aqueous lubricants with the use of ecofriendly, fatty acid-derived additives. The protic ionic liquid crystal bis(2-hydroxyethyl)ammonium stearate (DES) has been added to 50:50 water+ethylene glycol (W–EG) to obtain (W–EG)+0.5%DES; (W–EG)+1%DES and (W–EG)+2%DES emulsions. The new lubricants have been studied in sapphire-AISI (American Iron and Steel Institute) 316L stainless-steel pin-on-disk sliding contacts. The addition of DES reduces the friction coefficient by up to 76% and wear rate by up to 80%, with respect to (W–EG). The best performance is found for the emulsions with the lower proportion of DES (0.5 and 1 wt.%). These results have been related to viscosity and turbidity values. Wear mechanisms have been studied by Scanning Electron Microscopy/Energy Dispersive X-ray Spectroscopy (SEM/EDX) and by Raman microscopy. While W–EG shows a severe abrasive mechanism, no abrasion marks are present inside the wear track after lubrication with (W–EG)+0.5%DES, the emulsion with the lowest wear rate. After lubrication with W–EG, an increase in oxygen content is observed inside the wear track, as determined by EDX and confirmed by Raman microscopy, which shows the presence of iron oxides. The addition of DES reduces these oxidation processes.

Strongly enforced mobility restrictions to deter the spread of COVID-19 severely impacted tourism, a pivotal economic sector of the Balearic Islands. Little is known about the experiences of the most economically affected groups, such as hotel housekeepers. This study aimed to explore the experiences and concerns of hotel housekeepers (approximately 13,000 worked in the Balearic Islands before the pandemic) during the first stages of the COVID-19 lockdown. Semi-structured interviews were conducted by telephone in April of 2020. Thematic analysis was used for interpretation. Eighteen hotel housekeepers were interviewed. Main experiences and concerns identified were: (a) distress due to employment status and economic situation, (b) concerns for children’s education, (c) health-related concerns, mainly regarding the possibility of infecting someone, and (d) feelings related to home confinement (e.g., sense of security against infection, tedium, and boredom). Uncertainty permeated all discourses, generating feelings of fear and distress, particularly related to employment status and the general economic situation. Our findings shed light on the impact of public health measures to control COVID-19 spread in the different areas of life of hotel housekeepers, one of the most economically affected occupational groups. The trade-off between economics and health must be considered in future decisions on public health.