Scientists at the National University of Singapore (NUS) have demonstrated a new way through which it is possible to convert plastic bottle waste into aerogels. This discovery has made a significant contribution towards resolving the global issue of plastic waste.
The PET aerogels developed by the NUS-led research team using plastic bottle waste – a world’s first – is soft, flexible, durable, extremely light and easy to handle. They also demonstrate superior thermal insulation and strong absorption capacity.
These properties make them attractive for a wide range of applications, such as for heat and sound insulation in buildings, oil spill cleaning, and also as a lightweight lining for firefighter coats and carbon dioxide absorption masks that could be used during fire rescue operations and fire escape.
Associate Professor Hai Minh Duong said, “Plastic bottle waste is one of the most common types of plastic waste and has detrimental effects on the environment. Our team has developed a simple, cost-effective and green method to convert plastic bottle waste into PET aerogels for many exciting uses. One plastic bottle can be recycled to produce an A4-sized PET aerogel sheet. The fabrication technology is also easily scalable for mass production. In this way, we can help cut down the harmful environmental damage caused by plastic waste.”
Scientists took almost 2 years to demonstrate this technology completely. These PET aerogels are versatile enough that scientists can give them different surface treatments to customize them for different applications.
Professor Nhan Phan-Thien from the Department of Mechanical Engineering at NUS Faculty of Engineering said, “Our PET aerogels are very versatile. We can give them different surface treatments to customise them for different applications. For instance, when incorporated with various methyl groups, the PET aerogels can absorb large amounts of oil very quickly. Based on our experiments, they perform up to seven times better than existing commercial sorbents, and are highly suitable for oil spill cleaning.”
Prof Nhan explained, “By adopting PET aerogels that are coated with fire retardants as a lining material, firefighter coats can be made much lighter, safer and cheaper. It is also possible to produce low-cost heat-resistant jackets for personal use.”
When coated with an amine group, the PET aerogel can quickly absorb carbon dioxide from the environment. Its absorption capacity is comparable to materials used in gas masks, which are costly and bulky. To illustrate this application, the team embedded a thin layer of PET aerogel into a commercial fine particle mask to create a prototype mask that can absorb both dust particles and carbon dioxide effectively.
Prof Nhan said, “In highly urbanized countries like Singapore, the carbon dioxide absorption masks and heat-resistant jackets made using PET aerogels can be placed alongside fire extinguishers in high-rise buildings to provide added protection to civilians when they escape from a fire.”
Assoc Prof Duong said, “Masks lined with amine-reinforced PET aerogels can also benefit people living in countries such as China, where air pollution and carbon emission are major concerns. Such masks can be easily produced, and can also potentially be made reusable.”
Now, scientists are looking further to make a simple surface modification to the PET aerogels for absorption of toxic gases such as carbon monoxide, which is the deadliest component of smoke.
This work was published in the scientific journal Colloids and Surfaces A in August 2018.