IISc breaks the plastic mould; finds new tech to recycle bottles

Bengaluru: A team at the Indian Institute of Science (IISc), Bengaluru, has made a significant breakthrough in plastic recycling, potentially revolutionising how post-consumer plastic waste is reused.

Plastic pollution remains a pressing global issue. Each year, approximately 391 million tonnes of plastic are produced, but only about 8% is recycled. The rest accumulates in landfills, is incinerated or pollutes natural ecosystems.

One of the key challenges in recycling plastics — especially polyolefins, commonly used in packaging and containers — is the loss of strength and durability after processing.

To address this, IISc researchers have developed a method to enhance recycled plastic quality by incorporating material from discarded PET bottles, such as those used for water and soda.

Prof Suryasarathi Bose from the Polymer Processing Group, Department of Materials Engineering, IISc, explained the issue: "Post-consumer recycled plastics (PCR) often have poor strength and durability due to contamination with food or medical waste during the recycling process. Our goal was to upcycle these PCR plastics so they could be directly used in 3D printing applications.”

Before the breakthrough, the properties of the material were improved by blending PCR plastics with virgin plastic. "This mixture contains about 40% virgin plastic, which increases carbon dioxide demand, making it difficult to precisely estimate CO₂ savings,” Bose added.

The researchers chemically break down PET plastic into smaller, useful building blocks. These PET components are then added to recycled polyolefins using a process called melt extrusion, a standard plastic manufacturing method.

Lead inventors Indranil and Ketaki noted: “This mixture forms a crosslinked polymer— a material that is more stable, easier to reshape, and significantly stronger than conventional recycled plastic.”

More versatile material

The newly developed material lasts longer and is less prone to degradation over time.

Unlike traditional recycled plastics, which often struggle in high-performance applications, this version is stronger, more durable, and can be reshaped and reused multiple times.

To test the material’s viability, the researchers partnered with a start-up, VoILA 3D, and successfully used a robotic 3D printer to create large, sturdy structures —something previously unachievable with standard recycled plastic.

"This technology, which enables 3D printing using recycled plastics, is likely the first of its kind,” Bose said. “We have also replicated the process using milk packets and have filed a patent.”