Javiera Sepúlveda-Carter

Chicken eggshells are an abundant waste product from the food industry, composed mainly of calcium carbonate (~96%) along with proteins, and have demonstrated potential as reinforcing agents in biodegradable polymeric matrices

The growing impact of fossil-based plastics on the environment has driven interest in bioplastics such as polylactic acid (PLA), a biobased and compostable polyester widely used in food packaging but with limited properties

This study explores reusing discarded industrial polylactic acid (PLA), such as defective parts, scraps and burrs, for food contact applications. Reprocessing of PLA (PLA-RP) was simulated via melt extrusion, and the obtained pellets were characterized in terms of viscosity average molecular weight (M_v), melt flow index (MFI), the presence of non-intentionally added substances (NIASs) and the absence of metals to ensure that no substances exceeded the specific migration limits (SMLs). A slight reduction in the M_v, accompanied by an increase in the MFI, was observed in PLA-RP. In virgin PLA, fewer compounds were detected, likely related to residual additives. A higher variety and concentration of volatile and non-listed compounds were observed in reprocessed PLA (PLA-RP), with three exceeding their assigned Cramer class thresholds, requiring further evaluation. Most identified substances were typically linked to thermal degradation or potential additives for reprocessing. In both the virgin and reprocessed materials, all substances with SMLs remained below applicable thresholds, including trace metals. The PLA-RP was further processed into films by means of a compression moulding process. The structure, mechanical behaviour, thermal stability and water vapor transmission rate were comparable to those of virgin PLA, indicating no significant changes. The overall migration level tested in a fatty food simulant remained below regulatory limits. The materials fully disintegrated under laboratory-scale composting conditions in less than 3 weeks. Thus, reprocessed PLA shows great potential as a non-migrating material of interest in the sustainable food packaging field.

This study explores reusing discarded industrial polylactic acid (PLA), such as defective parts, scraps and burrs, for food contact applications. Reprocessing of PLA (PLA-RP) was simulated via melt extrusion, and the obtained pellets were characterized in terms of viscosity average molecular weight (Mv), melt flow index (MFI), the presence of non-intentionally added substances (NIAS) and the absence of metals to ensure that no substances exceeded the specific migration limits (SMLs). A slight reduction of the Mv, accompanied with an increase of the MFI was observed inf PLA-RP. In virgin PLA, fewer compounds were detected, likely related to residual additives. A higher variety and concentration of volatile and non-listed compounds was observed in reprocessed PLA (PLA-RP), with three exceeding their assigned Cramer class thresholds, requiring further evaluation. Most identified substances are typically linked to thermal degradation or additives, for reprocessing. In both materials, all substances with SMLs remained below applicable thresholds, including trace metals. The PLA-RP was further processed into films compression moulding. The structure, mechanical behaviour, thermal stability, and water vapor transmission rate were comparable to those of virgin PLA, indicating no significant changes. The overall migration level tested in a fatty food simulant remained below regulatory limits. The materials fully disintegrated under laboratory-scale composting conditions in less than 3 weeks Thus, reprocessed PLA shows great potential as a non-migrating material of interest in the sustainable food packaging field.

A Service-Learning methodology has been employed by professors and students at the Universidad Politécnica de Madrid to design and conduct two educational tours: "Spanish Enlightenment and the discovery of three chemical elements" and "The ‘altos del hipódromo’, a significant area during the 'Silver Age' of Spanish culture (1868-1936)". The objectives include: providing a holistic education integrating science with art, history, and architecture; nurturing skills such as data research, teamwork, oral presentation, and creativity; disseminating cultural content widely to the general people; and deepening the understanding of Madrid's architectural and cultural heritage. Tailored for diverse audiences including international participants, scientific conference attendees, and students from specific areas, these tours also involve students and faculty from architecture, building, and urban planning backgrounds. This article reflects on these experiences, evolving into discussion of topics such as Madrid's urban development, historical cartography, architectural styles (Neoclassical, Iron, Functionalism, Neo-Mudéjar…), the progression of historical buildings, the lives and works of prominent architects, and the intersection between architectural heritage and tourism.

Recycling post-consumer plastics for food contact applications is crucial for the circular economy; however, it presents challenges due to potential contamination and regulatory requirements. This review outlines the current European and U.S. legislation governing recycled plastics in food contact materials (FCM). The European Food Safety Authority (EFSA) mandates the evaluation and authorization of recycling processes. This includes examining input/output flows, prioritizing the use of previously authorized FCM, and assessing decontamination efficiency through material-specific challenge tests. Additionally, it evaluates new installations intended to apply approved decontamination technologies. In contrast, the voluntary submission to the U.S. Food and Drug Administration (FDA) provides guidelines with general advice on methodologies and recommended parameters and challenge tests. Applications to the EFSA for non-PET materials, such as HDPE, PP, and PS, are reviewed, highlighting the challenges of each material. Recycled PS, with its lower diffusivity compared to polyolefins shows promise for food packaging, with potential as a next material approved for use in the European Union. Decontamination technologies for post-consumer PS are explored, including super-cleaning processes, solvent extraction, and industrial methods. The review emphasizes the need for multidisciplinary collaboration to address the uncertainties around potential contaminants and ensure the safety of recycled plastics for food contact applications.

Desde su constitución en diciembre de 2019, la Oficina de Aprendizaje-Servicio (ApS) de la UPM se ha dedicado a promover y difundir la metodología ApS en el ámbito de las enseñanzas de nuestra universidad. Nuestra misión es trabajar en colaboración con entidades externas a la UPM para abordar las demandas y necesidades sociales, utilizando los conocimientos de nuestros estudiantes y profesores para contribuir a la construcción de una sociedad más justa y equitativa. En línea con los Objetivos de Desarrollo Sostenible (ODS) y la Agenda 2030, se han impulsado convocatorias de proyectos de impacto social, colaborando estrechamente con otras oficinas con objetivos similares en diferentes universidades. Se han establecido numerosas colaboraciones con Ayuntamientos, Asociaciones, ONG, Fundaciones y centros de enseñanza, enfocadas en mejorar entornos desfavorecidos y apoyar a colectivos vulnerables en nuestro entorno. La positiva acogida de estas iniciativas ha generado un creciente interés por parte de nuestros docentes y estudiantes, reflejado en la participación en las actividades organizadas por la oficina. En cuanto a la difusión, el año pasado publicamos la primera edición del ebook "Experiencias de Aprendizaje-Servicio Universitario". En esta segunda edición, hemos recopilado algunas de las experiencias más destacadas realizadas durante 2023 por el profesorado y los estudiantes de nuestra universidad en el ámbito del AprendizajeServicio. Nuestra intención es continuar ampliando estas publicaciones con futuras ediciones, dando visibilidad a las iniciativas meritorias que se llevan a cabo en nuestra comunidad universitaria. Agradecemos sinceramente a todos los profesores que han contribuido a esta segunda edición con sus experiencias y esperamos que sirva como inspiración y guía para futuros proyectos de Aprendizaje-Servicio en nuestra universidad. ¡Gracias por su compromiso y dedicación!.