By Josh Perry, Editor [email protected]
Scientists at the National University of Singapore (NUS) announced a new process for turning common polyethylene terephthalate (PET) plastics into aerogels that have many real-world applications in a variety of industries.
Ultralight aerogel made from recycled plastic bottles could solve a host of modern issues. (NUS)
According to an article from the university, the aerogel differs from most aerogels in that it is soft, flexible, and very durable, while retaining the standard properties of being ultralight and porous. It also provides a new means for ridding of unwanted plastics, as one bottle can be converted into an A4-sized PET aerogel sheet.
“Another advantage of this new material is its versatility,” the article noted. “The team discovered that different surface treatments meant that the aerogel could be used for many diverse applications. For example, if the PET aerogel incorporates a variety of methyl groups on its surface, it has the ability to absorb large amounts of oil up to seven times more effectively than other commercially available products.”
Researchers also coated the aerogel with fire retardant chemicals and it was able to withstand temperatures as high as 620°C.
The research was recently published in Colloids and Surfaces A: Physicochemical and Engineering Aspects. The abstract read:
“Recycled polyethylene tetraphalate (rPET) fiber–silica aerogels are successfully developed from rPET fibers obtained from PET plastic bottle waste and tetraethoxysilane (TEOS). The rPET – silica aerogels are prepared through a direct gelation of silica on PET. rPET fibers are treated with dichloromethane to partially dissolve the fibers. The fibers are then dipped and allow to swell in TEOS/ethanol mixture, with the pH controlled to 2.5 using HCl to promote hydrolysis.
“After the acid hydrolysis, the pH was controlled to 7 with an ammonium hydroxide solution (NH4OH) to promote condensation. The surface modification is carried out in a trimethylchlorosilane (TMCS)/n-hexane solution and washed with n-hexane to dry at room temperature to prevent shrinkage.
“The developed rPET – silica aerogels exhibit super-hydrophobicity with an average water contact angle of 149.9°. Their thermal conductivity is approximately 0.037 W/m K. They have a very low compressive Young’s Modulus (0.95–4.19 kPa) and hence very soft.
“By utilizing rPET fibers, this work provides an alternative method of recycling PET plastic wastes which ultimately helps in reducing its detrimental impact to the environment. The developed aerogels can be used in several industrial applications such as heat insulation, filtering, sound insulation and absorption.”
|