IIT Bombay develops equipment for recycling waste plastics

IIT Bombay has developed an indigenous equipment for mechanical recycling of waste thermoplastic polymers to composites.

The indigenous equipment called single screw extruder, developed for mechanical recycling through melt-mixing of waste thermoplastic polymers and inorganic particulate fillers, can help manufacture and characterise polymer composites that can be molded to the required shape for making paver blocks, tiles, and bricks.

The instrument, named GolDN (pronounced as Golden) can be used for melt-mixing of waste thermoplastic polymers and inorganic particulate fillers to manufacture polymer composites.

The equipment incorporates some key parameters such as compression ratio and clearance depth to facilitate efficient mixing of waste polymers and fillers. It can be used to carry out melt mixing on a continuous basis. 

Currently available melt-mixing equipment are not designed for handling waste thermoplastic polymers that are often adhered by contaminants, as the barrel and screw system are not robust enough.

The technology, developed with the support of the Department of Science and Technology (DST), is now ready for commercialisation for carrying out melt-mixing operations in a laboratory environment. 

IIT Bombay claims the extruder can be made available at Rs5 lakh (by at least a sixth of the present cost) by avoiding the complex design and operating tools and including the indigenous fabrication that are required.

The researchers have also developed a TGeosA for obtaining thermogravimetric analyses of the polymer composites obtained from the melt mixing instrument. The instrument can test a sample size of up to 200 g that can incorporate the heterogeneity aspect of the materials being tested.

IIT Bombay has set up a pilot-scale unit, consisting of a shredder, a mixer cum preheater, and an extruder, for manufacturing polymer composites. This can be used to shred plastic waste, mix and preheat plastic waste and IBPs, and melt plastic waste along with IBPs followed by conveying at the end, respectively.

The field-scale plant has been developed by IIT Bombay in collaboration with Belagavi works of Hindalco Industries Ltd.