Examinando por Autor "Prolongo, Silvia G."
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Ítem 4D-Printed Resins and Nanocomposites Thermally Stimulated by Conventional Heating and IR-Radiation(ACS, 2021) Cortés, A.; Aguilar, Jose L.; Cosola, A.; Fernández Sanchez-Romate, Xoan Xosé; Jiménez-Suárez, A.; Sangermano, M.; Campo, M.; Prolongo, Silvia G.The shape memory (SM) capabilities of nanocomposites based on two photocurable acrylated/methacrylated resins, doped with carbon nanotubes (CNTs), and manufactured by digital light processing 3D printing were investigated. The mechanical properties and glass transition temperature (Tg) can be tailored in a broad range by varying the weight ratio of the two resins (Tg ranging from 15 to 190 °C; Young’s modulus from 1.5 to 2500 MPa). Shape fixity (SF) and recovery (SR) ratios are strongly influenced by the temperature being significantly higher at temperatures close to the Tg. The results confirm that the SF strongly depends on the stiffness of chain segments between cross-linking points, whereas the SR mainly depends on the cross-link density of the network. CNT addition barely affects the SF and SR in the conventional oven, whereas the recovery speed using IR heating is significantly increased for the doped nanocomposites due to their higher IR absorbance.Ítem Graphene Oxide/Polylactic Acid-Based Face Mask to Combat H3N2: A Strategy against Influenza(ACS, 2024-03-14) Vázquez-López, Antonio; de la Vega, Jimena; Collado, Ignacio; Carmona, Franciso Javier; Prádanos, Pedro; Prolongo, Silvia G.; Wang, De-YiPersonal protective equipment such as face masks has become a fundamental tool to fight against virus-filled airborne droplets, preventing their widespread and the emergence of pandemics. While most face masks avoid the passing of airborne particles via a filtration effect, their protection effectiveness can be further increased by developing techniques based on antiviral coatings, which can inhibit virus replication. Among different coatings, carbon-based coatings are considered very appealing due to their low price and high antiviral properties. Most importantly, proper material selection during mask manufacturing is becoming more crucial as the high demand and consumption of common polypropylene face masks have grown into a huge environmental hazard. Herein, we present a potential face mask system based on nanoplatelets of graphene oxide (GO) spray coated via a simple one-step procedure over a poly(lactic acid) textile fabric, allowing a homogeneous coating. The incorporation of GO does not affect the textile structure nor affect its air permeability, while it increases its water contact angle, potentially preventing droplet trespassing. The antiviral efficiency was tested against Influenza A virus (H3N2) (strain A/Hong Kong/8/68), reaching a high reduction with no cytotoxic effect observed.Ítem Microhardness and wear behavior of nanodiamond-reinforced nanocomposites for dental applications(Wiley, 2024-10-04) Moriche, Rocío; Artigas-Arnaudas, Joaquín; Chetwani, Bhanu; Sánchez, María; Campo, Mónica; Prolongo, Margarita G.; Rams, Joaquín; Prolongo, Silvia G.; Ureña, AlejandroIn polymer-based dental composites, wear is a three-body wear system mainly abrasive, because of the food particles and wear products suspended in the oral cavity, which are transferred to the microcavities of the surface of the replacements. Due to this fact, the incorporation of nanodiamond as reinforcement in these polymer–matrix composites, which promotes the creation of a solid lubricant tribofilm surface could be advantageous. With the reinforcement of nanodiamonds, BisGMA/TEGDMA-based composites increase their microhardness by 95%–420%. A maximum hardness exceeding 65 HV is achieved with a reinforcement of 3.2 wt%. The specific wear rate of neat BisGMA/TEGDMA is near 10−4 mm3/Nm and the Archard's coefficient is 2.6 × 105. The incorporation of a content of 1.6 wt% ND is enough to cause a diminution of ~78% in the friction coefficient and a reduction of the specific wear rate and Archard's coefficient of ~50%. Nevertheless, the addition of relatively high contents reduces the effectiveness of photoinitiation and photocuring, which is related to the scattering and absorption of light radiation by ND. This causes a significant decline in elastic properties starting at 50 μm from the surface. Highlights Photocuring polymer resin was successfully reinforced with nanodiamonds. Microhardness increases from 95% up to 420%, close to commercial composites. Friction coefficient and wear rate are reduced with 1.6 wt% nanodiamonds. High levels of reinforcement reduce the effectiveness of photocuring.Ítem Modifications induced in photocuring of Bis- GMA/TEGDMA by the addition of graphene nanoplatelets for 3D printable electrically conductive nanocomposites(Elsevier, 2019-11-10) Moriche, Rocío; Artigas, Joaquín; Reigosa, Luis; Sánchez, María; Prolongo, Silvia G.; Ureña, AlejandroThe incorporation of nanoreinforcement in photocurable polymeric matrices can strongly affect the degree of curing and properties of the final nanocomposites as well as the process parameters for 3D printing. Particularly, the addition of GNPs in contents from 1 up to 10 wt% limits the degree of curing to 60% in Bis-GMA/TEGDMA. The increase up to 10 wt% causes a diminution of ~20% in the mentioned property. Additionally, the maximum thickness that can be cured by UV light abruptly decreases with the GNPs content, being ~400 μm when using 1 wt% and below 20 μm for nanocomposites filled with 10 wt%. Above the percolation threshold, the electrical conductivity of the photocured monolayers is dependent on the curing time, making possible the use of this materials as self-sensor of the degree of curing in additive manufacturing technologies.Ítem MXene multi-functionalization of polyrotaxane based PCMs and the applications in electronic devices thermal management(Elsevier, 2024-10-01) Yin, Guangzhong; López, Alba Marta; Collado, Ignacio; Vázquez-López, Antonio; Ao, Xiang; Hobson, Jose; Prolongo, Silvia G.; Wang, De-YiThe aim of this work was to improve the thermal conductivity and electromagnetic shielding of the leakage proof phase change materials (PCMs), in which a polyrotaxane (PLR) was used as a support material to encapsulate PEG 1k or PEG 6k and MXene as multi-functional filler. The PCMs can be processed conveniently by a hot press and the PEG 1k containing samples showed excellent flexibility. We conducted a systematic evaluation of the phase transition behavior of the material, thermal conductivity and electromagnetic shielding performance tests. Notably, the PCMs achieved a high enthalpy values (123.9–159.6 J/g). The PCMs exhibited an increase of 44.3 %, and 137.5 % in thermal conductivity values with higher MXene content (5 wt%) for PLR-PEG6k and PLR-PEG1k, respectively, and show high shape stability and no leakage during and after phase transition. The introduction of MXene can significantly improve the electromagnetic shielding performance of PCM composites. Typically, higher conductive samples (samples which contain high MXene contents) offer a higher EMI SE shielding, reaching a maximum of 4.67 dB at 5.6 GHz for PLR-1K-MX5. These improvements solve the main problems of organic PEG based PCMs, thus making PLR-PEG-MXene based PCMs good candidates for thermoregulators of both solid-state disks and smart phone. It is worth pointing out that the sample PLR-1k-MX5 can decrease 4.3 °C of the reference temperature during cellphone running. Moreover, the temperature of the protecting sheet in the simulated solid state disk with PCM was significantly lower (showing a decreasing of 7.9 °C) compared with the blank sample.Ítem Smart electroactive self-repairable coating involving end-of-life aircraft prepregs by mechanical recycling(Elsevier, 2024-09) Espeute, Emma; Martinez-Diaz, David; Vázquez Sánchez, Pablo; Martín, Zulima; Rosario, Gilberto Del; Jiménez-Suárez, Alberto; Prolongo, Silvia G.The environmental impact of the Carbon Fiber Reinforced Polymers (CFRPs) industry, particularly due to waste generation during manufacturing and end-of-life phases, is compelling major industrial entities to reconsider a circular economy approach for their materials and to comply with emerging regulations. This study explores the potential of recycled carbon fibers (rCFs) derived from the mechanical recycling of prepreg waste. Mechanical recycling was selected for its cost-effectiveness and moderate environmental impact, recovering short rCFs with lengths below 200 μm. These rCFs, which retain excellent electrical properties, are incorporated into an epoxy matrix with Polycaprolactone (PCL) to create a multifunctional coating with self-healing capabilities. The resulting composite material exhibited significant improvements in electrical conductivity, achieving up to 16.50 S/m, and demonstrated effective Joule effect heating, exceeding 200 °C with 20 V applied for a composite containing 15 wt% rCF. The self-healing efficiency for surface cracks, activated by the Joule effect, reached 80–90 %, resulting in a 99 % reduction in energy consumption compared to conventional oven heating. Notably, the self-healing mechanism was characterized in real-time within a scanning electron microscope for the first time, providing a comprehensive evaluation of the process. This innovative coating offers promising applications in aviation for anti-icing, deicing, and maintenance reduction, as well as in residential settings as an energy-efficient floor heating solution. This research underscores the potential of mechanically recycled CFRPs to produce high-value, sustainable materials, promoting a circular economy and reducing the environmental footprint of the aeronautical sector