Felices fiestas!

Cromado Sin Cromo

El proyecto SAMDOKAN estudia la implementación de una tecnología sustituta del cromado de plásticos, que utiliza cromo hexavalante, un material muy tóxico y riesgoso para los trabajadores que lo manipulan.

La empresa Avanzare, especialista en tecnología de nanopartículas lidera la investigación que se centra, no en la tecnología, la cual ya existe, sino en la forma de hacer accesible esta para el actual mercado del plástico.

La novedosa tecnología, denominada SAM (autensamblado molecular), evita el uso de cromo hexavalente y otros compuestos tóxicos usados para el pretratamiento de las superficies a cromar. Logrando un acabado idéntico y un menor costo en sistemas de seguridad en las plantas de acabado metálico.

Por si fuera poco, la tecnología es fácil de utilizar no sólo en ABS, sino también en materiales que podrían explotar este acabado, usados abundantemente en la industria automotriz, como el Polipropileno y la Poliamida o Nylon.

Cómo lograr que tus baterías ‘muertas’ duren ocho veces más

Cuando tiras tus baterías desechables AA porque tu control remoto ya no funciona, en realidad todavía tenían alrededor del 80% restante de su energía.

Una nueva cubierta para pilas, que llegará este otoño a Amazon con un precio de 2.50 dólares y con el nombre de Batteriser, promete extender la vida útil de tus baterías hasta ocho veces más al extraer su energía restante... la cual estabas a punto de tirar a la basura. La diminuta cubierta de acero inoxidable de 0.1 milímetros de grosor, presenta una placa de circuito increíblemente pequeña que fue construida para aprovechar la energía restante de la batería.

Las baterías AA arrancan con 1.5 voltios de energía, pero el voltaje desciende a medida que son usadas. Una vez que las baterías bajan de los 1.35 voltios, parecen estar muertas, aun cuando todavía tienen mucho combustible.

Según Bob Roohparvar, fundador de Batteriser y profesor de informática en la Universidad Estatal de California, esto se parece a lo que sucede con un tubo de pasta de dientes.

"Si tan solo aprietas desde arriba, únicamente obtendrás una parte del contenido del tubo", dijo Roohparvar.

Por ejemplo, una batería AA común dejará de funcionar después de 240 minutos de uso proveyéndole energía a un control remoto, 95 minutos proveyéndole energía a unas bocinas portátiles, o tan solo 38 minutos proveyéndole energía a un juguete a control remoto. Roohparvar afirma que el Batteriser puede obtener 1,185 minutos de un control remoto (5 veces más energía), 570 minutos de unas bocinas portátiles (6 veces más) o 355 minutos de un juguete a control remoto (9 veces más).

Batteriser puede continuar proveyendo una carga de 1.5 voltios de las baterías que realmente se han descargado hasta 0.6 voltios.

Roohparvar dice que espera revolucionar el mercado de las baterías desechables, el cual tiene un valor de 14,000 millones de dólares. Hay 5,400 millones de dispositivos en uso que funcionan con baterías y 15,000 millones de baterías desechables se compran cada año en todo el mundo. Una casa promedio en Estados Unidos cuenta con 28 dispositivos que funcionan con pilas dentro de ella.

El Batteriser estará disponible en variedades de baterías AA, AAA, C y D-Cell, y se venderán por paquetes de cuatro a un precio menor de 10 dólares. A ese precio, dice Roohparvar, la tecnología "se paga sola", si consideramos que una batería AA común tiene un precio de 2.50 dólares y que el Batteriser prolonga la duración de una batería hasta ocho veces.

Dijo que es una solución más barata que las baterías recargables. Y esas baterías recargables comúnmente se fabrican de litio, lo cual no es compatible con muchos de los productos que funcionan con baterías.

"El Batteriser te ofrece el rendimiento de las baterías de litio al precio de las alcalinas", dijo Roohparvar.

Después de una campaña que lanzará Indiegogo en julio para los pioneros, Roohparvar dice que el Batteriser comenzará a venderse en Amazon en el otoño. También dijo que él ha estado hablando con los ejecutivos de Wal-Mart acerca de la venta de las cubiertas para batería en el futuro.

Aunque Roohparvar dice que sus patentes impedirían que los fabricantes de baterías simplemente añadan la tecnología del Batteriser a sus baterías, dijo que más adelante podría estar abierto a conceder licencias. También dijo que algún día Batteriser podría asociarse con Duracell o con Energizer y vender las baterías y los Batterisers como un solo paquete.

Fuente: http://m.cnnexpansion.com

New Polymers Set to Revolutionize 3D Printed Implants

Over recent months we have seen a real change in the evolution of 3D printing technology. New 3D printing systems are being introduced every week, which are now relatively affordable, more energy efficient, compact and thankfully quieter. But it is with the range of new polymers now available that offers the most exciting aspect of 3D printing technology development. We are now leaving behind the traditional ABS and PLA which we have become so used to, fond of and somewhat bored with. However, with innovative new materials this is all about to change.

New polymers, new challenges

In our lab at the Welsh Centre for Printing and Coating (WCPC) we have started to trial these fascinating new polymers, testing them for durability, creep and extrudability. We have had success with mixing metal and ceramic particles into polymers which makes parts look and feel like real metal and ceramic parts respectively. The great thing is that these materials, even with fine particles mixed into them, are still easy to extrude using standard 3D printing extrusion technology.

A thermoplastic elastomer (TPE) going by the name of Ninjaflex is fascinating, allowing for rubberised components to be fabricated. Another is an electrically conductive and piezoresistive carbomorph going by the name of "conductive ABS". By the end of the year we will see Tenax-based carbon fibre filaments becoming common and following on from this fibreglass materials becoming available in 2015.

New polyamide for bio-applications

So a few months ago I heard about Taulman introducing Nylon 645 filament, which is essentially polyamide. This is a fascinating material, being high strength (UTS 320MPa), biologically compatible and inert. For about $20 you can procure about 0.5kg which can subsequently  produce many hundreds of fascinating structural components.

One of the most exciting and closely watched new uses of this material is for producing patient specific 3D printed implants, such as for cartilage joint replacement. These are often more difficult than bone replacements as the part must accurately conform to an existing internal bone structure, be pliable enough to conform to unusual mounting methods. They must be inherently strong to keep the joint from becoming misaligned by stress, and most importantly, provide a long term slippery surface to the biological mating surface. During this process we produced a prototype cartilage joint replacement to trial this material. By careful extruding Nylon 645 at a speed of 20mm/sec and at an extrusion temperature of 250°C  we were able to produce a prototype precision implant.

Example of knee joint cartilage implant produced using Nylon 645, these are usually made from expensive titanium alloy.

One of the most significant features of 3D printing is the ability to print a part that is difficult or impossible to make with a traditional CNC machine. This implant needed to feature a number of intricate chambers for attachment to a bone and without 3D printing technology then these would otherwise be impossible to make. But in less than two hours the implant was produced complete to ±25µm degree of precision. Take these features from just a lab experiment and scale this process up then in theory one could print sensitive electrochemical components and sensors within this implant as well. The newly printed and pliable implants do split, break or tear and can be machine-washed and dried many times.

Custom prosthetics and implants made on-site

Recently, surgeons and doctors from the Hague University have determined that Nylon 645 meets and exceeds the requirements to support several possible uses inside and outside of the human body. From bone replacement to electronic sensor enclosures, hospitals and clinics can now design and subsequently print on-demand patient specific support components.

In the past, a prosthetic was designed specifically for a patient’s shape, weight and structure which required iterations of models and try-outs. With the combination of 3D scanning and on-demand 3D printing, a patient can now leave the hospital with a pliable prosthetic. These are designed specifically for their needs while at the same time being built on what we determined could be a slightly modified low cost home 3D printer.

Example of knee joint cartilage implant produced using Nylon 645, these are usually made from expensive titanium alloy.

The interesting thing to note is that now 3D printing offers us the opportunity to start high-tech enterprises, but in the style of old-school cottage industries. For the cost of perhaps now under $800 in theory one could start a custom medical implant business right at home. Thus, what is important is that the real power of 3D printing is starting to be realised and it is these materials which allow a whole range of new functional integrated components to be custom made, on demand and for low cost.

Taulman 645 Technical Specifications

645 Nylon co-polymer consists of the purest form of a delta transition of Nylon 6/9, Nylon 6 and Nylon 6T with a crystallinity optimisation process in addition to post-processing for maximum bonding during a 3D printing thermal transition process. Construction is from granule form through nylon extruding systems to a 12 station extrusion to draw, 4 chiller loops with 2 post processing stations to a final draw of 3mm or 1.75mm round line.

Material Properties

		Testing Standard
Water Absorption	3.09 %	ISO 62:2008 - Plastics -- Determination of water absorption
Mechanical Properties
Upper Tensile Strength	320MPa	ISO 527-5:2009 - Plastics -- Determination of tensile properties
Elongation at Break	>= 300 %	ISO 527-5:2009 - Plastics -- Determination of tensile properties
Melting Point	214 °C	ISO 3146:2000 Plastics -- Determination of melting behaviour (melting temperature or melting range) of semi-crystalline polymers by capillary tube and polarizing-microscope methods
Glass Transition Temp	68.2°C.	ISO 3146:2000 Plastics -- Determination of melting behaviour (melting temperature or melting range) of semi-crystalline polymers by capillary tube and polarizing-microscope methods
Processing Properties
Print Temperature	235 - 260 °C
Pyrolysis	350 - 360 °C
UV	There are no UV Inhibitors within 645 as they reduce bonding

Safety    

Nylon 645 meets the EU's "REACH" requirements as defined by the ECHA European Chemicals Agency.  There are no additives or chemicals in 645 that are listed in the REACH Directive. 645 Contains no toxic chemicals and is "inert" to the body.

¿CUÁLES SON LAS PRINCIPALES VENTAJAS DEL MASTERBATCH?

1. Limpieza en área de producción. A diferencia de los pigmentos en polvo, el masterbatch no mancha ni tiene volatilidad, lo que hace que el trabajo se realice en un ambiente limpio y sin contaminación.

2. Gran uniformidad debido a una óptima dispersión del pigmento. Estos resultados son difíciles de obtener cuando se utilizan directamente pigmentos en polvo, ya que las partículas de pigmento tienen una fuerte tendencia a reagruparse y formar aglomerados de gran cohesión, difíciles de separar con el simple trabajo mecánico del proceso de transformación, por lo que es usual que cuando se utilicen pigmentos en polvo aparezcan puntos o ráfagas de color.

3. Fácil manipulación y pesado. El hecho de que el masterbatch se presente en forma de pellets hace que se facilite su manipulación así como simplificar el proceso de pesado. Pesar pellets es mucho más fácil que pesar polvo o líquidos.

4. Dosificación. Permite la dosificación automática. El pellet no se adhiere a las paredes de la tolva, y por lo tanto se pueden utilizar dosificadores automáticos.

5. Reducción de las líneas de flujo en colores perlescentes y metálicos debido a su mejor dispersión. En pigmentos en polvo, debido a las fuerzas eléctricas y a la absorción de humedad, existe la tendencia a formar grumos, y por lo mismo, líneas de flujo en pigmentos de partícula plana como son los metálicos. El master reduce este defecto sensiblemente.

6. Reducción en la absorción de humedad. A diferencia de los pigmentos en polvo, que son altamente higroscópicos, los masters tienden a tener una menor absorción de humedad, e inclusiva algunos a ser prácticamente impermeables.

7. Se eliminan los grumos. Al no tener las características de los polvos, el masterbatch no mantiene fuerzas fuertes de cohesión que hace que se produzcan grumos, y por lo tanto permite una dispersión uniforme.

8. Rapidez de limpieza. Al no tener polvo en el proceso de moldeado, la limpieza de tolvas es prácticamente inmediata. En el cañón, el no tener polvo mezclado con resina evita que se adhiera a las paredes del propio cañón, lo cual podría formar placa contaminante con el tiempo. El masterbatch evita esta formación de placa.

SOLVING MYSTERIES OF CONDUCTIVITY IN POLYMERS

Materials known as conjugated polymers have been seen as very promising candidates for electronics applications, including capacitors, photodiodes, sensors, organic light-emitting diodes, and thermoelectric devices. But they've faced one major obstacle: Nobody has been able to explain just how electrical conduction worked in these materials, or to predict how they would behave when used in such devices.

The conjugated polymers fall somewhere between crystalline and amorphous materials and that's caused some of the difficulty in explaining how they work.

Crystals have a perfectly regular arrangement of atoms and molecules, while amorphous materials have a completely random arrangement. But the conjugate polymers have some of both characteristics: regions of orderly arrangement, mixed randomly with regions of complete disorder.

A scanning tunneling electron micrograph (STEM) of the polymer material shows its division into crystalline regions (light areas of orderly dots) and the amorphous, disordered matrix, which is seen as the dark background. The original 2-D STEM views were rendered into 3-D form to create this visualization.

"Some models have tried to explain how these materials behave, but there's been no direct evidence," Ugur says, for which model matches the reality. "Here, we've shown that the effect of crystallite size" —the sizes of the ordered domains within the material—plays a crucial role.

That's because the trickiest part of conduction in such materials is what happens when charge carriers—in this case ions, or electrically charged atoms —reach the edge of one type of domain and have to "hop" into the next.

In bulk materials, those ions can go in any direction. But in this polymer, which can be very thin, there are fewer neighboring crystalline domains to which an ion can hop. With fewer options, conduction is more efficient, Ugur says, adding that, "As you get thinner, the conditions [for conduction] improve, even though the material didn't change."

Diagram shows the possible orientations of PEDOT polymer chains relative to a substrate surface (white plane at bottom), in experiments carried out by the MIT team.

Previous attempts to model the electrical behavior of such materials had focused on their chemical properties. "People didn't take into account the crystallites," says Karen Gleason, the Alexander and I. Michael Kasser Professor of Chemical Engineering. As a result, understanding of the electrical properties of such materials "remains incomplete even after decades of investigation," the team writes in their paper.

Kripa Varanasi, an associate professor of mechanical engineering, says, "We wanted to develop materials where we can independently control their thermal and electrical properties. We were inspired to develop organic-inorganic interfaces as they can give rise to many new features that are not present in the corresponding bulk materials".

Varanasi explains that most of the time, electrical and thermal conductivity of materials go together, but achieving independent tuning of thermal and charge transport can lead to broad applications for thermal management, flexible electronics and photonics, thermoelectrics, and thermal and electrical cloaking.

The researchers analyzed a conjugated polymer known as PEDOT, known to have a promising combination of good electrical conductivity and stability. One key question that this new research may help to answer, Gleason says, is: "What is the upper limit for conduction in this polymer?".

That's information needed to assess its potential usefulness for various applications. When the material was first developed it had conductivity of between 1 and 10 Siemens per centimeter, or S/cm, Gleason says; over time, it was improved to a level of "close to 100." Now, with the new analysis carried out by this team, conductivities of over 3,000 S/cm have been achieved. By creating ultrathin layers that amplify the hopping mechanism, "We are able to achieve ultraconductive, as well as highly transparent, films," Varanasi says.

Other semiconducting materials used widely in electronics achieve even higher values, such as 8,000 S/cm in indium-tin-oxide, or ITO, Gleason says. But, she points out, those materials are stiff and brittle, whereas conjugated polymers are flexible, opening up potential applications in curved or flexible devices.

Although the research was conducted with PEDOT, Ugur says, the findings "should be generalizable to all conjugated polymers." (Polymers' structures consist of long chains; conjugated polymers are those that have at least one "backbone" consisting of alternating double and single chemical bonds, making them conductive).

PEDOT has a combination of three properties that give it great potential, Gleason says: electrical conductivity, transparency, and flexibility. "Anywhere that ITO is used, you could think of using this"—with added flexibility. The polymer material could have applications in flexible solar cells, displays, and touch screens, the team says, among other possibilities.

"This work is a significant step in the development and understanding of conductive polymer films," says Ruud Schropp, a professor of thin-film photovoltaics at the Eindhoven University of Technology in the Netherlands, who was not involved in this work. He adds that the finding "explains the counterintuitive effect that ungrafted, amorphous PEDOT films have higher conductivity than grafted films. This insight could provide an avenue for bringing the conductivity of polymer films close to that of their transparent oxide counterparts, such as ITO."

by: http://phys.org/news/2015-07-mysteries-polymers.html

Engineering plastics and polyurethanes in the BMW i3

Example: BMW i3

For several innovative components in the BMW i3, the electric vehicle from the BMW Group, the chemical company BASF supplies versatile plastics and supported part development with extensive construction know-how. These include the backrests of the front seats, key reinforcement parts in the carbon fiber body, and the rear seat shell.

Innovations in the BMW i3

BASF:  “By bringing together all our plastics expertise in the division Performance Materials, we can offer customized solutions to innovative customers such as the BMW Group and their suppliers worldwide as well as support them during component construction. With the BMW i3, the BMW Group has taken a ground-breaking step into the future of the automotive industry, and BASF’s intelligent solutions are making a key contribution here.”

More information:
 http://www.plasticsportal.net/wa/plasticsEU~en_GB/function/conversions:/publish/common/upload/engineering_plastics/bmw_i3_flyer.pdf