Photosensitive acrylates containing bio-based epoxy-acrylate soybean oil for 3D printing application

Stereolithography is a 3D-printing process that is rapidly shifting from being an expensive and limited technology to an affordable, precise, and fast method of mass production. However, most of the current resins are petroleum-based, which makes them toxic, non-degradable and with poor biocompatibility. In this study, a standard petroleum-based resin containing urethane acrylate and acrylic monomers was combined with epoxy-acrylate soybean oil (EASO), aiming to reduce its impact on the environment. Ratios varying from 10 to 50 wt% of EASO were incorporated into the commercial resin while maintaining the viscosity low, between 0.27 and 1.06 Pa s. The printed samples showed good quality and complete integration between the layers. The addition of 50 wt% of EASO increased the samples elongation at break by 108% (from 2.3% to 4.8%) and decreased the contact angle by 26.4% (from 72 to 53°). Moreover, the mixture showed good thermal and swelling stability and tensile strength in the range of other commercial cured systems. The addition of EASO may significantly contribute to the exploitation of greener materials, which well matches today's circular economy concept

Variabilidad espacial en determinaciones de carbono, nitrógeno, fósforo y ph, de un muestreo sistemático de suelo

p.43-48En una unidad taxonómica planosol somero, se realizó un muestreo sistemático tridimensional. Se obtuvieron 100 muestras en una cuadrícula diseñada sobre una hectárea. En el ensayo se incorporaron dos fuentes de variabilidad: a) distinta profundidad, b) distintos manejos. Sobre ellos se realizaron las determinaciones de carbono total, nitrógeno total, fósforo asimilable, pH actual y pH potencial. En todos los casos se describe la población a través de su media muestral, varianza y coeficiente de variación. Con estos datos se calcula el número mínimo de muestras a extraer, para un error permitido de hasta el 15 por ciento de su media. Los datos fueron analizados estadísticamente, comprobándose que el carbono y nitrógeno presentan diferencias altamente significativas al muestrearse en las dos profundidades propuestas en el ensayo. En fósforo se encontraron diferencias altamente significativas tanto en las distintas profundidades como manejos. En pH actual y potencial hay igualdad de datos para las variables seleccionadas. Se concluye que para que un muestreo resulte representativo de un área y los resultados obtenidos tengan un mínimo de seguridad, deberán tenerse en cuenta los siguientes aspectos: la profundidad de muestreo, el manejo dado al suelo y la característica del elemento a medir

Investigation of Epoxy-Acrylate Soybean Oil as A Bio-Enhancer for 3D Printing Application

In this study, a standard crude oil-based commercial resin containing urethane acrylate and acrylic mon-omers was combined with a biobased monomer, namely epoxy-acrylate soybean oil (EASO), at ratios varying from 10 to 50 wt.% and 3D printed, using a stereolithographic apparatus. The printed samples exhibited good quality and complete integration between the layers. Besides, the addition of increasing EASO loadings decreased the stiffness and mechanical strength of the samples (which exhibited mechanical properties similar to other commercially available photosensitive systems), while increasing their ductility and wettability. Therefore, the addition of EASO may significantly contribute to the exploitation of greener materials, which well matches today's circular economy concept

Preparation and characterization of 3D-Printed biobased composites containing micro- or nanocrystalline cellulose

Stereolithography (SLA), one of the seven different 3D printing technologies, uses photosensitive resins to create high-resolution parts. Although SLA offers many advantages for medical applications, the lack of biocompatible and biobased resins limits its utilization. Thus, the development of new materials is essential. This work aims at designing, developing, and fully characterizing a bio-resin system (made of poly(ethylene glycol) diacrylate (PEGDA) and acrylated epoxidized soybean oil (AESO)), filled with micro- or nanocellulose crystals (MCC and CNC), suitable for 3D printing. The unfilled resin system containing 80 wt.% AESO was identified as the best resin mixture, having a biobased content of 68.8%, while ensuring viscosity values suitable for the 3D printing process (>1.5 Pa s). The printed samples showed a 93% swelling decrease in water, as well as increased tensile strength (4.4 ± 0.2 MPa) and elongation at break (25% ± 2.3%). Furthermore, the incorporation of MCC and CNC remarkably increased the tensile strength and Young’s modulus of the cured network, thus indicating a strong reinforcing effect exerted by the fillers. Lastly, the presence of the fillers did not affect the UV-light penetration, and the printed parts showed a high quality, thus proving their potential for precise applications

Highlights from faraday discussion on designing nanoparticle systems for catalysis, London, UK, May 2018

The 2018 Faraday Discussion on “Designing Nanoparticle Systems for Catalysis” brought together leading scientists to discuss the current state-of-the-art in the fields of computational chemistry, characterization techniques, and nanomaterial synthesis, and to debate the challenges and opportunities going forward for rational catalyst design. The meeting was a vivid discussion of how the communities accummulate knowledge and on how innovativeness can be combined to have a stronger scientific impact. In the following, we provide an overview of the meeting structure, including plenaries, papers, discussion points and breakout sessions, and we hope to show, to the wider scientific community, that there is great value in continued international discussion and scientific collaboration in these fields

Development of an antioxidant formula based on peanut by-products and effects on sensory properties and aroma stability of fortified peanut snacks during storage

An antioxidant formula based on peanut skins and hulls, was developed and characterized for total and single polyphenols, and antioxidant power, considering the contribution provided by each peanut by‐product. Then, it was evaluated for its effect on sensory properties and aroma stability of peanut bars over a 100‐day period. To this purpose, snacks fortified and not with the natural additive were experimentally produced

Siembra directa y labranza convencional : cambios que produce a largo plazo la fertilización sobre las fracciones de carbono y nitrógeno del suelo

p.313-317Se llevó a cabo un ensayo sobre un suelo Argiudol típico (Marcos Juárez. Prov. de Córdoba), con el objetivo de determinar la magnitud de las pérdidas y los cambios que produjo la fertilización nitrogenada sobre diferentes fracciones de carbono y nitrógeno, en un cultivo de maíz durante 15 años. Se cuantificaron pérdidas significativas de carbono orgánico y nitrógeno total al comparar los suelos cultivados con un suelo nativo. Este efecto fue más evidente en labranza convencional que con siembra directa. La fertilización sólo afectó a las fracciones lábiles determinadas: nitrato, amonio, nitrógeno hidrolizable y carbono soluble; la variable más sensible en detectar los cambios provocados por los sistemas de labranza y la fertilización fue el nitrógeno hidrolizable