Soap made from waste plastic – Photo Guardian
The resin has chemical properties similar to fatty acids – one of the main components of soap.
Guoliang Liu – Associate Professor of Chemistry at Virginia Tech University (USA) and author of a study published in the journal Science & Technology. Science – indicates that this analogy shows that polyethylene can be converted to fatty acids and then to soap.
The problem is that the molecular size of plastics is very large, around 3,000 carbon atoms, while fatty acids are much smaller.
This “problem” was solved by Mr. Liu by chance. “It was Christmas Eve. I’m looking at the fireplace. When firewood burns, smoke is released, which is made up of tiny wood particles. I wonder if burning plastics is the same way.”
Wood is mainly composed of polymers such as cellulose. Burning wood breaks these polymers down into shorter chains, then turns them into smaller gas molecules before being completely oxidized to carbon dioxide.
“If we break down similar synthetic polyethylene molecules, but stop the process before they are completely broken down into smaller gas molecules, we get short-chain polyethylene-like molecules,” explains Liu. I like it.
Mr Liu and his colleagues have created an oven-like reactor that can be used to safely burn plastics. The temperature at the bottom of the furnace is hot enough to break the polymer chains, while the temperature at the top is low enough to prevent them from breaking too quickly.
Scientists collected the remains and found that the product they formed was short-chain polyethylene, a wax. Then they started turning the wax into soap.
“This is the first plastic soap in the world. It has a unique color,” Mr. Liu said.
Plastic Pollution: A Global Challenge
Mr. Liu’s method is performed on the two most popular plastics today: polyethylene and polypropylene. They account for nearly half of the total 200 million tons of plastic waste each year. Over 80% of plastic waste goes to landfill, while less than 10% is recycled.
One advantage of this new method is that it works on “end-of-life” plastics, which are generally not recyclable.
“Plastic pollution is a global challenge. This is one of the big problems our society is facing. The best solution is to reduce the use of plastic in all activities.”
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