Researchers at the Tuskegee University in the US have developed nanoparticles from eggshells, in a bid to enhance the strength ofbiodegradable packaging material.
The team of researchers experimented with various plastic polymers, prior to developing the biodegradable packaging material that can bend but does not easily break.
They initially developed a mixture comprising 70% polybutyrate adipate terephthalate (PBAT), a petroleum polymer, and 30% polylactic acid (PLA), a polymer derived from corn starch.
The team created nanoparticles by breaking the eggshells, using ultrasonic waves, into fragments that are more than 350,000 times smaller than the diameter of a human hair.
The shells were first washed, ground up in polypropylene glycol and then broke down into nanoparticles. A small fraction of these particles was infused into the PBAT and PLA mixture in a laboratory study.
Eggshells have been chosen as they are porous, lightweight and mainly composed of calcium carbonate, a natural compound that easily decays.
Tuskegee University researcher Vijaya K Rangari said: "These nano-sized eggshell particles add strength to the material and make them far more flexible than other bioplastics on the market.
"We believe that these traits, along with its biodegradability in the soil, could make this eggshell bioplastic a very attractive alternative packaging material."
The researchers said the addition of tiny shards of eggshell made the mixture 700% more flexible than other bioplastic blends, making the material ideal for use in retail packaging, grocery bags and food containers, including egg cartons.
They presented their work at the 251st National Meeting & Exposition of the American Chemical Society (ACS) on 15 March at the San Diego Convention Center.
Image: Researchers used eggshell nanoparticles to increase the strength and flexibility of bioplastic material. Photo: courtesy of Vijaya Rangari / Tuskegee University.