Context: 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 characterize polymer composites that can be molded to the required shape for making paver blocks, tiles, and bricks.

Present status of recycling:  At present, commercially 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.

About the equipment:

• IIT Bombay has developed an instrument named GolDN (pronounced as Golden) for melt-mixing of waste thermoplastic polymers and inorganic particulate fillers to manufacture polymer composites.
• It can carry out melt mixing as a continuous process, particularly in laboratory conditions, to replicate the real-life conditions as compared to other conventionally available instruments.
• The researchers at the institute considered some key parameters such as compression ratio and clearance depth to facilitate efficient mixing of waste polymers and fillers.
• The above technology, developed with the support of Department of Science and Technology (DST) through Waste Management Technologies, is now ready for commercialization for carrying out melt- mixing operations in a laboratory environment. It can bring down the cost of this instrument to INR 5 lakhs (by 6-8 times at least) 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 setup facilitates a sample size as high as 200 g that can incorporate the heterogeneity aspect of the materials being tested.

Thermoplastic Polymers

They are types of polymers that can be melted by heating and recasted by cooling almost infinitely. Thermoplastic polymers are a type of plastic that can be repeatedly melted and reshaped without losing their original properties.

• They are commonly used in a wide range of applications, including packaging, automotive parts, and household items.
• Examples of thermoplastic polymers include Polyethylene, Polypropylene, and Polyvinyl Chloride (PVC).
• These can be classified as polymers with a high molecular weight.
• They can also attain a high strength supported by the structure of the intermolecular chains. 
• When the temperature near thermoplastic polymers is increased, the intermolecular force starts to weaken which then yields a liquid with high viscosity.