Detroit — Plastic grocery bags seem to be everywhere, and they've become public enemy No. 1 to the general public. But a university professor explained research into how to convert bags into high-strength yarn for weaving into useful products like mats, purses, maybe even gloves.
Cottage industries have sprung up to make plastic yarn into items for sale online or to give out to homeless people.
"We tried to use polymer science to help the people who are making plastic bag wraps to make better plastic bag wraps," Donggang Yao of the Georgia Institute of Technology, said at Antec in Detroit. Yao is a professor of the School of Materials Science and Engineering at the Atlanta school.
A visiting group of master's and doctorate students and an associate professor from China conducted the yearlong research project at Georgia Tech.
Yao pointed out that several trillion plastic bags are used every year around the world, and some become ocean waste or can clog drainage pipes. Also, the recycled material has to compete price-wise with virgin polyethylene, he said.
Yao said recycled grocery bags typically are recycled using melt processing, but an alternative is converting the bags into yarn, then braiding them together using simple equipment available on the internet.
Yao said this could be a good home-based business.
The yarn is made by cutting the bags and looping them together. Georgia Tech students tested different ways to tie the strips of bags together. An important step is to stretch the yarn by a drawing process, then apply heat to convert into a high-strength plastic yarn.
Home workers could use weights to stretch the bags and boiling water to heat the yarn, he said.
In the lab, the polymer students also did tensile and rheology tests of the yarn to gauge strength and durability.