Liquid in Five Minutes Instead of 16 Hours
Researchers from the Institute of Biological and Chemical Systems, the Institute for Biological Interfaces, and the Institute for Chemical Technology and Polymer Chemistry of KIT have actually now discovered that the crosslinked sodium polyacrylate polymers deteriorate under UV light after the uptake of water.
They are so loose that they swim in water and turn into liquid fibers,” Pavel Levkin, Professor at the Institute of Biological and Chemical Systems, discusses. For their studies, the scientists cut out the liners from traditional diapers, wetted them with water, and exposed them to a light of 1000 W.
The Recycled Polymers Can Be Used in Various Ways
The team then utilized known procedures to convert the liquid into new adhesives and dyes. “The observation that the substance is soluble and processible was of high value. The majority of most likely, it can be become many other products,” the researcher describes.
For their tests, the scientists used tidy diapers. It is also possible to separate the superabsorbers from used diapers. “Hence, there is no reason why close-to-reality usage need to not be possible,” Levkin says.
Recommendation: “Diapers to Thickeners and Pressure-Sensitive Adhesives: Recycling of Superabsorbers by means of UV Degradation” by Shuai Li, Johannes M. Scheiger, Zhenwu Wang, Birgit Huber, Maxi Hoffmann, Manfred Wilhelm and Pavel A. Levkin, 7 September 2023, ACS Applied Materials & & Interfaces.DOI: 10.1021/ acsami.3 c06999.
Superabsorbers become liquid under UV light after they have used up sufficient water. They can be reused. Credit: Ken Pekarsky, KIT
Water and UV radiation efficiently and swiftly break down the crosslinked polymers in diaper liners without the usage of any chemicals. This procedure allows the recycled plastic molecules to be repurposed for diverse applications.
Superabsorbent materials, like salt polyacrylate, are key elements in numerous hygiene and medical products, consisting of diapers, plasters, and dressing materials. Typically, these crosslinked polymers, known for their high absorbency, are insoluble in water. Recycling them has traditionally necessitated the usage of strong acids.
The acids, nevertheless, “cut” the chains stabilizing the polymers after about 16 hours at 80 degrees Celsius and, thus, made it possible for recycling. This process is intricate and expensive, which is why superabsorbers have barely been reused.
Superabsorbers become liquid under UV light after they have taken up enough water. Normally, these crosslinked polymers, understood for their high absorbency, are insoluble in water. The team then utilized known processes to convert the liquid into brand-new adhesives and dyes. For their tests, the scientists used tidy diapers. It is also possible to separate the superabsorbers from utilized diapers.