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Issue 05/2019

  • Text
  • Textiles
  • Fibers
  • Polymers
  • Compostable
  • Barrier
  • Biodegradable
  • Products
  • Plastics
  • Biobased
  • Packaging
  • Materials
  • Bioplastics
Highlights: Fibres/Textiles/Nonwovens Barrier Materials Cover Story: Lightweighting PBAT

Fibers & Textiles

Fibers & Textiles PLA-fibres in medical applications New composite material for non-acidic degradation of medically used PLA PLA 3D-printing + Microgel Solution spinning Electrospinning Fig. 2: In the framework of the pHMed project different processes for achieving PLA structures on various scales are developed Fig. 1: Wet spinning equipment for PLAfilament spinning By: Georg-Philipp Paar Dept. of Biohybrid & Medical Textile (BioTex) Institut für Textiltechnik der RWTH Aachen University Aachen, Germany Biodegradable materials, such as polyglycolic acid (PGA) and polylactic acid (PLA), are used commercially in medicine for sutures, osteosynthesis systems and drug delivery systems. The degradation of these materials inside the body offers a big advantage in implants, like meshes and support structures (scaffolds), as a second operation for removal is not necessary and long-term foreign body reactions are prevented. Furthermore, a gradual reduction of the mechanical support function is possible, which allows load transfer from the temporary structure to the healing tissue, unlike when using metal implants. However, the degradation of PLA and PGA in the body is problematic, as acidic degradation products are released, which can cause a local acidosis. This may lead to inflammation or even tissue death. To compensate the acidic environment and local drop of the pH in the tissue buffering salts were incorporated in PGA filaments in the cooperation of the Dept. of Biohybrid & Medical Textiles (BioTex) and the Institut für Textiltechnik ITA (both RWTH Aachen University). Unfortunately, the buffering capacity was insufficient and the salts caused instabilities in the spinning process. A promising alternative are amine based microgels, developed by the DWI - Leibniz Institute for Interactive Materials (also RWTH Aachen University). These colloidal polymers show a high buffering capacity while being suitable for the use in medical products because of a good biocompatibility. PLA filaments with microgels were dry spun, as the microgels function is preserved only at low temperatures. The buffering of the pH value was successful, but the filaments showed a low tensile strength with a high variation in values. Current research results show that a wet spinning process is a promising alternative, as it allows production of PLA filaments with increased tensile strength. First experiments indicate that the filaments can be processed further by braiding and knitting technology to produce sutures and scaffolds. In addition to the production of textile filaments also other manufacturing processes are developed within the project pHMed. For example, the DWI integrated the microgels into electrospun nonwovens, which could be used for skin or cartilage replacement. The EnvisionTec GmbH (Gladback, Germany) tries to incorporate microgels into 3D printed PLA structures. With this flexible process it is possible to build up three-dimensional structures, which can be used for stabilizing materials after a bone fracture. An important aspect for industrialization of the material – the upscaling of the microgels synthesis – is investigated as well by DWI within the framework of the project. Acknowledgement: The Project pHMed is supported by the European Regional Development Fund North Rhine- Westphalia (EFRE.NRW). www.biotex-aachen.de | www.ita.rwth-aachen.de 24 bioplastics MAGAZINE [05/19] Vol. 14

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