Page 90 - TEXtalks September/October 2021
P. 90

90                                                                                                                          Avex and Majotae
                                  4D printed


                  wearable medical                                                                                                   introduce hemp


                                        devices                                                                                      fibers in knitting





               Researchers from the University of Freiburg and   degree the splint will bend when exposed to
               the University of Stuttgart have developed a novel   moisture. They have used orthotic devices as a
               method of 4D printing wearable medical devices   motivating example, as there is immense potential
               that self-adjust to the patient's anatomy. When the   for passive adaptivity in wearable assistive
               shape of a 3D printed structure is designed to   technologies for medical and sports applications.
               morph over time, it is called 4D printing. These
               geometry shifts can be induced in many ways,   The printed structure also included several
               with some of the most common being electrical   swelling and stabilizing layers that work in
               stimulation, heat, and moisture. Many 4D printed   conjunction with the bend lines to achieve a
               objects are pre-programmed to morph using      coiling helix-like form. Additionally, the team
               intelligently placed layers and folds, which can   printed pockets on the splint's surface, which
               contract and expand to give the desired effect.   pushes the helix outwards to create tension in the
                                                              device, ultimately resulting in the contraction of
               The Freiburg team turned to the air potato, a vine   the entire splint. This enables the device to tighten
               plant capable of climbing trees by winding itself   around the wearer's arm for a personalized, snug
               around the host's trunk. Air potatoes sprout   fit, supporting the wrist.
               outgrowths called stipules, which help tension the
               winding stem and exhibit a squeezing force on   The researchers have successfully developed a
               the host plant. This allows the air potato to work   material programming approach for designing
               its way up to its host, bringing it closer to that   and 4D-printing bio-inspired motion mechanisms                 Hemp is a natural, sustainable material that
               much-needed sunlight. In a bid to emulate the   that adapt to environmental stimuli. So far, the                    is gaining attention globally. Until now, only
               movement mechanism of the air potato, the      process is still limited to existing base materials                  woven textile could be produced using hemp
               researchers employed a computational design    that respond to moisture. The researchers said                       fibers, which was limited in use due to the
               strategy that involved selectively printing 'bend   that they are hoping that in the future, inexpensive            characteristics of hemp fibers. Now, by
               lines' into the geometry of the splint itself. Like   materials that also respond to other stimuli will             developing a more resistant thread than the
               creases in a piece of paper, these bend lines are   become available for 3D printing and can be used                previous one, which would break when spun,
               designed to determine how, where, and to what   with this process.                                                  plain weaving and the production of knitted
                                                                                                                                   fabric made from 100-percent hemp fiber
                                                                                                                                   became possible. Avex Entertainment Inc.
                   Scientists discovered enzymes with the ability to recycle polyester                                             and Majotae started limited sales of 100%
                                                                                                                                   hemp T-shirts. Majotae is a brand that utilizes
              Plastics have been a problem for the environment, including polyesters used to manufacture various textile           modern technology to resurrect the actual
            products. Researchers are trying to find different ways to recycle plastics. Recently, scientists at Bio-Optimised     texture of the hemp cloth that Japanese
            Technologies to keep Thermoplastics out of Landfills and the Environment (BOTTLE) Consortium have reported             people have used since ancient times.
             an enzyme-based plastic recycling method that is more energy-efficient and better for the environment. They
                used enzymes for recycling PET, a standard plastic in single-use beverage bottles, clothing, and food              The most significant feature of majotae is its
              packaging. BOTTLE Consortium included scientists from the US Department of Energy’s (DOE’s) National                 realization of a texture that overturns the
                             Renewable Energy Laboratory (NREL) and the University of Portsmouth.                                  image of typical hemp, i.e., feeling stiff and
                                                                                                                                   rough. Due to this, Avex can expand the use
               PET ranks among the most abundantly produced synthetic polymers globally, with 82 million metric tons               of hemp cloth not just for shirts and kimono,
             produced annually; roughly 54 % of PET is used to manufacture textiles for clothing and fibers for carpets. An        but also knitted fabric products such as
             analysis shows enzyme-recycled PET has potential improvement over conventional, fossil-based methods of               T-shirts and sweatshirts that until now are
             PET production across a broad spectrum of energy, carbon, and socioeconomic impacts. If further developed             commonly made from cotton and synthetic
                and implemented at scale, the concept could lead to new opportunities for PET recycling and create a               fibers. The developed technology leaves the
                 mechanism for recycling textiles and other materials made from PET that is traditionally not recycled.            fabrics with a silky touch and cotton-like
                                                                                                                                   softness.
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