Scientists make tough plastics recyclable 

Scientists make tough plastics recyclable 

Thermosets, which include rubber used for tires, epoxies, and polyurethanes are found in lots of products that need to be durable as well as heat-resistant, such as electrical devices or cars and trucks. A disadvantage to these products is that since the chemical bonds holding them with each other are stronger than those present in various other materials such as thermoplastics they can not be easily recycled or broken down after use.

A method to modify thermoset plastics with a chemical linker that makes the materials a lot easier to break down and still maintain the mechanical strength that makes them so beneficial has been developed by the chemists of Massachusetts Institute of Technology (MIT).

The outcomes of the research study published in the journal Nature. The study showed that the scientists could produce a degradable version of a thermoset plastic called pDCPD, break it down into a powder, and develop more pDCPD using the powder. A theoretical model was also proposed by the team, which suggested that their method could be suitable for a vast array of plastics and other polymers.

The senior author of the study was Jeremiah Johnson, a professor of chemistry

at MIT and the first author of the paper is Peyton Shieh, an American Cancer Society Postdoctoral Fellow at MIT.

Johnson said that this study introduces a fundamental design principle that the team believes is basic to any type of thermoset with this fundamental architecture.

Hard to recycle

In addition to thermoplastics, thermosets are one of the two major types of plastics. Polyethylene as well as polypropylene used for single-use plastics like food wrappers and plastic bags come under thermoplastics. Thermoplastic materials are manufactured by heating tiny pellets of plastic until they melt, after that molding them into the preferred form and allowing them to become solid by cooling.

75% of worldwide plastics production are thermoplastics, which can be recycled by heating them once again until they become liquid, so they can be remolded into another form or another product.

Johnson said that similar processes are used to make thermoset plastics, however, once they are cooled down from a liquid into a solid form, it is really challenging to return them to a liquid state, which is why the bonds that form in between the polymer molecules are strong chemical attachments called covalent bonds, which are very hard to break. Thermoset plastics will typically melt when heated before they can be remolded.


Scientists make tough plastics recyclable 

Author: Sruthi S


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