Application News
Application News Bio-tiles Even tiles can be organic – if they are made of renewable raw materials. They are more resource efficient than their ceramic counterparts and unlock new creative options for design. The bio-tiles consist of a mixture of linseed oil epoxy, various natural fibres and diatomaceous earth, a material that is procured from fossilized diatoms. New bio-based tile systems, like the ones designed at the Fraunhofer Institute for Mechanics of Materials IWM in Halle, Germany, are more environmentally friendly, lighter-weight and – depending on their manufacturing and material properties – more resource- and energy-efficient than conventional ceramic materials. “The composite is not hard as glass and brittle like conventional epoxy, but flexible and more pliable instead. This makes it easier to work with the tiles,” as Andreas Krombholz, scientist in the natural composites division at IWM, describes another advantage. They also put a completely new spin on architectural perspectives. In the moulding process, they can be shaped on an entirely customized basis, and shaped into squares, triangles or circles, for example. Even patterns and colours can be tailor-made. Another design advantage: By adding fluorescent pigments to the blend, they are transformed into light tiles. This means they can be used both outdoors and indoors, serving as illuminated guideposts on floors and walls. The same bio-tiles can also be installed in kitchens and bathrooms and can serve as indoor floor coverings. There are cost benefits to both producer and customer here: this is because the tiles can handle the impact noise abatement directly, so an entire work step can be dropped from the production process. MT www.iap.fraunhofer.de Innovative office chair The Generation by Knoll ® work chair revolutionized the world of office seating with significant support from material science, processing and expert application development at DuPont. The chair embraces the idea of elastic design – where a product rearranges itself in response to its user. Knoll Inc. is headquarted in East Greenville, Pennsylvania, USA. Key to the chair’s flexing and supportive features is the use of high-performance DuPont thermoplastics in the form of renewably sourced DuPont Hytrel ® RS TPC-ET for the Flex Back Net with no compromise on properties and other DuPont materials (TPC-ET, PBT) for the Dynamic Suspension control. Designed by Formway Design of New Zealand, Generation uses high-performance DuPont materials in a way that had never before been seen in the furniture industry. The Flex Back Net and the Dynamic Suspension control work together to give the chair its flexibility and structure – allowing it to move to suit the extended range of motion required in a contemporary working environment – and yet still retain the memory of its original position. The Flex Back Net, which deploys renewably sourced Hytrel, supports many different postures and allows for a wide range of multi-dimensional movement – not just from front-to-back, but also from side-to-side. Users also can push against the Flex Top of the backrest and it will bend over to support their arm as they turn and chat with a colleague. Thanks, in part, to its use of renewably sourced materials from DuPont, Generation was the first product in the furniture industry to be rated Sustainable Platinum by the SMaRT© Consensus Sustainable Product Standard, a comprehensive, transparent, sustainable product standard that measures a product’s environmental, economic and social benefits over its life cycle and throughout its global supply chain, from raw materials extraction through reclamation or re-use. MT www.knoll.com www.dupont.com This bio-tile not only comes with an excellent ecological balance, it even unlocks new design options. Using the inherent properties of Hytrel RS TPC-ET for the Flex Back Net,the chair literally flexes as you change position, responding to your movements (Image: Knoll, Inc.) 44 bioplastics MAGAZINE [01/13] Vol. 8
From Science and Research Efficient drug release by an absorbable foam In a novel approach for the treatment of common diseases of the urinary bladder (e.g. overactive bladder) a system for the controlled release of drugs (drug delivery system, DDS) is currently being developed using a special polylactide based foam material. The system is placed directly into the urinary bladder. Thus, the active medical agent has a locally lasting effect in the bladder and won’t affect the whole body like with orally administered tablets. Also a regular catheterization in short time intervals (several times a day) is not required. The DDS consists of drug-loaded polymer matrix (so called microspheres), which are embedded in a foamed, absorbable carrier system (cf picture). The drug release and the excretion of the system are controlled by the degradation of the carrier system. In this joint research project the development of the foamed carrier system is a scope of the Institute of Plastics Processing (IKV) at the RWTH Aachen University. Other project partners are Dr. Pfleger GmbH, Hemoteq AG, DWI at the RWTH Aachen and the urology of the hospital of the RWTH Aachen (all Germany). The carrier system is manufactured in a so-called CESPprocess (Controlled Expansion of Saturated Polymers). The technology of the CESP-process enables the possibility of processing temperature-sensitive materials, like the used poly (D,L-lactide-co-glycolide)-co-PEG (here Resomer RGP d5055 or d50155 resp. by Evonik, Darmstadt, Germany). The material can be processed in a CO 2 atmosphere at high pressure (approx. 50 bar) at low temperatures of approx. 50 °C. By an extension of the CESP-process a powdery polymer microsphere mixture can be foamed specific via a pressure controlled, continuous variable discharge. The adjustment of the degradation of the carrier system to medically necessary periods is possible by the termination of the foam structure. For reproducible manufacturing of the carrier system in the range of micrograms a dosing unit and adapted cavities are integrated into the process chain. Because of the extension of the CESP-process by a reproducible dosing of the materials and an optimized controlling several more applications in the scope of absorbable, drug-eluting implants, such as porous osteosynthesis plates or stents are possible. The investigations set out in this report received financial support from the German Federal Ministry of Education and Research (BMBF) (No. 13 N 11306). MT www.ikv-aachen.de polymermatrix with drug microsphere carriersystem with microspheres bioplastics MAGAZINE [01/13] Vol. 8 45
