AsianScientist (Feb. 26, 2018) – A research team from the National University of Singapore (NUS) Faculty of Engineering has devised a fast, cheap and green method to convert cotton-based fabric waste into highly compressible and ultralight cotton aerogels. They published their findings in Colloids and Surfaces A: Physicochemical and Engineering Aspects.
Aerogels are among the lightest materials in the world and are highly porous with strong absorption capacity and low thermal conductivity. These unique properties make aerogels highly suitable for applications in areas including oil-spill cleaning, personal care products such as diapers, as well as for heat and sound insulation.
Although aerogels were first created in the 1930s, this advanced material has not been widely adopted by industries due to its high production cost. Leading aerogel scientists around the world are therefore actively looking at ways to improve the manufacturing and consumption of different types of aerogels.
In the present study, researchers led by Associate Professor Duong Hai Minh developed cotton aerogels from cotton-based fabric waste that can be easily compressed. They demonstrated that the aerogels could very quickly recover up to 97 percent of their original size when placed in water.
“This new eco-friendly cotton aerogel is a major improvement from the aerogel that our team had previously developed using paper waste. It is highly compressible, hence storage and transportation costs could be greatly reduced,” said Duong.
The scientists also noted that their cotton aerogels could be fabricated within eight hours—about 20 times faster than current commercial fabrication processes. The aerogels are also stronger, making them more suitable for mass production.
In addition to characterizing the aerogels, the researchers also demonstrated how their invention could be used to control excessive bleeding. Existing hemorrhage control devices comprise a syringe filled with small capsules of cellulose-based sponge coated with chitosan, a natural agent derived from the shells of shrimp and other crustaceans that promotes blood clotting.
The syringe is inserted into the wound to release the capsule, which expands and applies pressure on the wound to stop the blood flow. However, the expansion and absorption rates of cellulose-based sponges are still relatively slow.
To address these limitations, the researchers developed highly compressible hybrid cotton aerogel pellets which are more effective than cellulose-based sponges for treatment of deep hemorrhagic wounds. These pellets, comprising an optimal mix of cotton and cellulose aerogels coated with chitosan, are simple and cost-effective to produce, and they can be easily integrated into a clinical syringe to be used as a hemorrhage control device. The cotton aerogel pellets are also biocompatible, hence they can be safely administered for treatment.
“Each cotton aerogel pellet can expand to 16 times its size in 4.5 seconds—larger and more than three times faster than existing cellulose-based sponges—while retaining their structural integrity. The unique morphology of the cotton aerogels allows for a larger absorption capacity, while the compressible nature enables the material to expand faster to exert pressure on the wound,” said Duong.
The article can be found at: Duong et al. (2018) Compressed Hybrid Cotton Aerogels for Stopping Liquid Leakage.
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Source: National University of Singapore; Photo: Pixabay.
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