Plastic bottles are one of the most common types of plastic waste, so the more you can find out how to recycle them, the better. With this in mind, researchers at the National University of Singapore (NUS) have developed a low-cost method for converting this plastic bottle into a very useful aerogel.
The NUS R&D team was led by Associate Professor Hai Minh Duong and Professor Nhan Phan-Thien. The materials used in the experiment were common polyethylene terephthalate (PET). The developer first made the PET into a fiber and then coated it with silica. From this step, the production process becomes quite complicated, but mainly involves chemical treatment of the fibers, allowing them to swell and then drying.
The resulting aerogel is light, porous, flexible and durable, and is the world's first to make PET into this material, which has many potential uses.
For example, if a variety of methyl compounds are applied to the surface of an aerogel, the oil absorption capacity is seven times that of other commercially available adsorbent materials. It can also be used as a thermal or acoustic insulation material in buildings, or when coated with an amine-based compound, it can be used as a filter to filter dust particles and carbon dioxide from reusable masks. Researchers are also investigating the surface of aerogels, designed to modify the material to adsorb toxic gases such as carbon monoxide.
However, the best use of aerogels may be considered as a protective insulation for firefighter jacket uniforms. When the material is coated with flame retardant chemicals, it can withstand temperatures up to 620oC (1,148oF). The aerogel weighs only about 10% of the protective insulation used by current firefighter jackets and is softer and more comfortable.
The National University of Singapore has applied for a patent for the technology and is now looking for a partner to help the product go on the market. A paper on this research was recently published in the journal Colloids and Surfaces A.