Poly(methyl methacrylate) as Healing Agent for Carbon Fibre Reinforced Epoxy Composites

Self-healing materials offer a potential solution to the problem of damage to fibre-reinforced plastics (FRPs) by allowing for the in-service repair of composite materials at a lower cost, in less time, and with improved mechanical properties compared to traditional repair methods. This study investigates for the first time the use of poly(methyl methacrylate) (PMMA) as a self-healing agent in FRPs and evaluates its effectiveness both when blended with the matrix and when applied as a coating to carbon fibres. The self-healing properties of the material are evaluated using double cantilever beam (DCB) tests for up to three healing cycles. The blending strategy does not impart a healing capacity to the FRP due to its discrete and confined morphology; meanwhile, coating the fibres with the PMMA results in healing efficiencies of up to 53% in terms of fracture toughness recovery. This efficiency remains constant, with a slight decrease over three subsequent healing cycles. It has been demonstrated that spray coating is a simple and scalable method of incorporating a thermoplastic agent into an FRP. This study also compares the healing efficiency of specimens with and without a transesterification catalyst and finds that the catalyst does not increase the healing efficiency, but it does improve the interlaminar properties of the material.This research was funded by the State Research Agency of Spain (AEI), under grant number PID2019-107501RB-I00/AEI/10.13039/50110001103

Cognitive Changes and Quality of Life in Neurocysticercosis: A Longitudinal Study

Neurocysticercosis (NCC) is one of the most common parasitic infections of the central nervous system. Cognitive changes have been frequently reported with this disease but have not been well studied. Our study team recruited a group of new onset NCC cases and a matched set of healthy neighborhood controls and new onset epilepsy controls in Lima, Peru for this study. A neuropsychological battery was administered at baseline and at 6 months to all groups. Brain MRI studies were also obtained on NCC cases at baseline and at 6 months. Newly diagnosed patients with NCC had mild cognitive deficits and more marked decreases in quality of life at baseline compared with controls. Improvements were found in both cognitive status and quality of life in patients with NCC after treatment. This study is the first to assess cognitive status and quality of life longitudinally in patients with NCC and provides new data on an important clinical morbidity outcome

El futuro del sector transporte: materiales compuestos auto-reparables

La auto-reparación, es la capacidad de un material, de repararse de forma autónoma, tras sufrir un daño por su uso, agresiones externas, etc. Este comportamiento es una alternativa eficiente para aumentar la vida útil de un material. En este trabajo, se analiza la capacidad auto-reparadora de matrices termoestables y elastómeros, materiales ampliamente usados en el sector transporte. Los resultados preliminares revelan una capacidad de reparación del 50 %. Estos resultados marcan el inicio en el desarrollo de materiales innovadores, que reducirán los contenidos de residuos y permitirán su reutilización, todo ello englobado dentro de los principios de economía circular.Se agradece al Ministerio de Ciencia, Innovación y Universidades (MICINN) por la financiación recibida (MAT2016-81138-R, MAT2015-73392-JIN) y a Signus por proveer el neumático fuera de uso empleado. Mónica Peñas Caballero agradece al MICINN por la beca FPI (Formación del Personal Investigador)

Nuevos avances en materiales compuestos reforzados con fibras

Los materiales compuestos poliméricos reforzados con fibra continua (FRP) se utilizan cada vez más como elementos estructurales en una gran variedad de sectores, como el transporte, energía, civil, marina, deporte, entre otros, gracias a sus excelentes propiedades mecánicas, alta resistencia y rigidez, buen comportamiento a fatiga, buena resistencia a la corrosión y bajo peso. Sin embargo, las demandas tecnológicas actuales exigen mejorar sus propiedades para ampliar su aplicación a condiciones más severas o extremas o aumentar su ciclo de vida. De este modo, en esta conferencia, se describen algunos de los avances realizados en el desarrollo de nuevos FRP con propiedades avanzadas. En concreto, en tres líneas de investigación: 1. Materiales compuestos jerárquicos, en los que se incorporan un refuerzo en dimensiones nanométricas, como nanotubos de carbono y grafeno para mejorar sus propiedades interlaminares, una de las principales debilidades de los FRP. Además, con la incorporación de estas nanopartículas de carbono se consigue dotar al FRP de multifuncionalidad como conductividad térmica o eléctrica. 2. Materiales compuestos con capacidad autorreparadora. Los FRP son vulnerables a accidentes de baja energía que generan fallos visibles sobre la superficie o interlaminares, que reducen la resistencia del material y terminan provocando su fallo. La tecnología actual requiere del desarrollo de FRP con capacidad autorreparadora, de manera que se pueda ampliar el tiempo de vida del material y abaratar los procesos de reparación del material. 3. Materiales compuestos sostenibles. Uno de los grandes problemas de los FRP es que no se pueden ni termoconformar ni reciclar por lo que al llegar al final de su vida útil terminan enterrados o almacenados en vertederos. Con objeto de cumplir con una economía 100% circular, es necesario desarrollar nuevos FRP sostenibles basados en resinas termoplásticas, en los que es posible recuperar los dos componentes mayoritarios, la fibra y la resina, en óptimas condiciones para volver a usarse en la fabricación de FRP de altas prestaciones

Poly(ethylene-co-methacrylic acid) coated carbon fiber for self-healing composites

We describe a simple and scalable method for incorporating thermoplastic agents into fiber reinforced polymers (FRPs). Poly(ethylene-co-methacrylic acid) (EMAA) nanoparticles were successfully deposited on the surface of carbon fibers via spray coating. EMAA was finely distributed and exhibited strong adhesion to the fibers. The EMAA-coated carbon fibers improved the fracture toughness and provided the FRPs with self-healing ability. The resulting healing efficiency, based on the recovery of the interlaminar fracture toughness, was above 40 % and gradually decreased after three repair cycles. The repair mechanism of the system involves the inherent flow capacity of the thermoplastic and formation of interfacial bridging between the two damaged interphases. This methodology allows pure resin to be used without any chemical modification or adverse effects on its viscosity, and the coated fiber can be stored until use.This research was funded by the Spanish Research Agency, grant numbers PID2019-107501RB-I00/AEI/10.13039/501100011033 and RYC-2017-22837. Monica ´ Penas-Caballero ˜ thanks a Predoctoral contract (BES-2017-079899Peer reviewe

Corrosion control by autonomous self-healing epoxy coatings based on superabsorbent healing agents

Metallic corrosion is an all-time dangerous and extremely expensive problem. Here, we present an autonomous self-healing polymer coating based on an epoxy resin and superabsorbent polymer (SAP) blend as an anticorrosion coating. Tailor-made coatings were manufactured by controlling the location of the SAP on the surface, middle, and bottom of the coating. The corrosion behavior and self-healing process of the coatings were analyzed at the macro, micro, and sub-micro scales using Electrochemical Impedance Spectroscopy (EIS). The SAP preferentially located at the bottom showed coating resistance values higher than 1 × 10 Ωcm over 10 days of immersion with 3-point defects. This configuration provided the best anticorrosion performance, preventing coating delamination, and protecting the metal from corrosion after surface damage, indicating better barrier properties. The SAP enabled local repair of the crack when in contact with water, minimizing the diffusion of oxygen and electroactive species, which are responsible for the corrosion of a metal.This research was funded by the Spanish Research Agency, grant numbers PID2019-107501RB-I00/AEI/10.13039/501100011033, and RYC-2017-22837. MPC acknowledges grant BES-2017-079899 funded by MCIN/AEI/10.13039/501100011033. VB would like to acknowledge financial support through the PID2019-104717RB-I00 project from the Spanish Ministry of Science and Innovation (MICI

Individual cognitive test scores within the processing speed composite at baseline and 6-month follow-up.

#<p>Significant difference within groups longitudinally (p≤0.05). Standard error follows mean test scores in brackets.</p

Composite age and education-adjusted test scores for major cognitive domains at baseline and 6-month follow-up.

<p>**Significant difference between NCC and Epilepsy groups cross-sectionally (p≤0.05). Standard deviation follows test scores in brackets.</p

Demographic and clinical summary of neurocysticercosis cases and controls.

<p>Abbreviations: SD: standard deviation, IR: interquartile range.</p

SF-36 transformed scale scores for major quality-of-life outcomes at baseline and 6-month follow-up.

<p>*Difference vs. Neighborhood Controls cross-sectionally (p≤0.07);</p><p>**Significant Difference vs. Neighborhood Controls cross-sectionally (p≤0.05);</p>#<p>Significant difference within groups longitudinally (p≤0.05). Standard error follows transformed test scores in brackets.</p