GolDN: IIT Bombay’s Innovation for Polymer Composite Production

The problem of plastic waste management is a global challenge that requires innovative solutions. According to a report by Earth Action, India generates about 9.46 million tonnes of plastic waste annually, out of which 98.6% is mismanaged and ends up polluting the environment. Recycling plastic waste not only reduces its environmental impact, but also creates value-added products that can be used for various applications.One such innovative solution is GolDN, an instrument developed by researchers at IIT Bombay with the support of the Department of Science and Technology (DST). GolDN stands for Golden Laboratory Device for Melt-mixing of Nanocomposites, and it is a single-screw extruder that can mechanically recycle waste thermoplastic polymers into composites by melt-mixing them with inorganic particulate fillers (IPFs).

What is GolDN and how does it work?

GolDN is different from commercially available melt-mixing equipment, which are not designed to handle waste polymers that are often contaminated by dirt, moisture and other impurities. GolDN has a robust barrel and screw system that can efficiently mix waste polymers and IPFs under laboratory conditions, replicating the real-life scenarios of recycling. The researchers have optimized some key parameters such as compression ratio and clearance depth to facilitate effective mixing and dispersion of the components.

The composites produced by GolDN can be molded into various shapes and sizes, such as paver blocks, tiles and bricks, which can be used for construction and landscaping purposes. The composites have enhanced mechanical, thermal and electrical properties compared to pure polymers, and they also reduce the dependency on virgin materials.

Some examples of IPFs that can be used with GolDN are fly ash, red mud, silica fume, carbon black, graphene oxide, etc. These IPFs are either industrial by-products or nanomaterials that can improve the performance of the composites. The researchers have tested different combinations of polymers and IPFs to optimize the properties of the composites.

What are the additional features of GolDN?

The researchers have also developed a thermogravimetric analyzer (TGeosA) to test the composites obtained from GolDN. The TGeosA can handle a large sample size of up to 200 g, which incorporates the heterogeneity aspect of the materials being tested. The TGeosA can measure the weight loss of the composites as a function of temperature and time, which gives information about their thermal stability and degradation behavior.

In addition, the researchers have indigenously fabricated a pilot-scale setup for manufacturing polymer composites from waste plastic polymers and IPFs. The setup consists of a shredder, a mixer cum preheater and an extruder, which perform the functions of shredding the plastic waste, mixing and preheating it with IPFs, and melt-mixing it followed by conveying it to the end product. The technology has been developed in collaboration with Hindalco Industries Ltd., and it is at the technology readiness level (TRL) of 9, meaning that it is ready for commercialization.

What are the benefits of technology ?

The technology of GolDN has several advantages over conventional methods of plastic waste recycling. It is cost-effective, as it reduces the need for complex design and operating tools, and uses indigenous fabrication. It is also environmentally friendly, as it reduces the amount of plastic waste going to landfills or incinerators, and creates useful products that can replace natural resources. It is also socially beneficial, as it can create employment opportunities for waste collectors and processors.

GolDN is an example of how scientific research can address real-world problems and create sustainable solutions. By recycling waste plastic polymers into composites, GolDN can help in achieving resource circularity and environmental conservation for plastics.

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