3-Nov-2022: An indigenous technology from IIT Madras can now produce new-generation super-abrasive tools

A newly developed technology can now produce new-generation multi-point/single-layer superabrasive tools for advanced grinding applications to meet high productivity and energy-efficient material removal requirements. The tools produced also have enhanced tool life.

Grinding industries have aired their voices for developing advanced superabrasive cBN/diamond tools that meet high productivity and energy-efficient material removal requirements and customization based on local needs.

A research team led by Dr. Amitava Ghosh at IIT Madras has used advanced chemical bonding technology with an application-specific novel formulation of filler material and controlled spacing of grits on the tools by an indigenously developed semi-automatic grit-printing device.

The team recommends application-specific-advanced coatings to develop such new-generation superabrasive tools. The novel formulation offers an excellent blend of strength, wear resistance, and wetting characteristics (ability to spread well in a liquid state with low contact angle on solid superabrasives during brazing). The grit-planting (planting/placing of grits in pre-defined co-ordinate position on grinding wheel's working surface) setup allows a manufacturer to print grit in customised pattern to suit the requirement of an application. The recommended coating enhances the durability of the bond, thus adding life to the developed tools.

In a nutshell, these superabrasive tools can be produced using active brazing technology with remarkably striking attributes of high crystal exposure above bond level. The joint strength and wear-resistant characteristics of bond of these tools are superior to those of their commercial counterparts. These tools can withstand more grinding force, offer significantly higher tool life, and execute load-free grinding of advanced materials with an extremely high material removal rate.

This indigenous tool supported by the Core Research Grant (CRG) of the Science and Engineering Research Board (SERB), a statutory body of the Department of Science and Technology (DST), offers a competitive cost with a superior quality tool, which is also tailor-made as per the needs of industries like aerospace, automobile, mining, and dental surgery.

The technology can produce new-generation tools with versatile geometries. The prototypes of various tools have been developed in the laboratory and are being experimentally test-simulated under industrial conditions. This innovative route of showcasing the novel pathway of manufacturing superabrasive tools has been published in "Journal of Manufacturing Process" recently, and patents filed are under review for approval.

This technology which fits the requirements of Make-in-India National Mission is under lab validation and is near-ready to be taken up by a start-up or any industry for a full-scale launch. The application-specific indigenous formulation of active fillers for joining superabrasives to metal substrates through state-of-the-art active-brazing technology is a critical novelty that may be exploited for large-scale manufacturing industries.

2-Aug-2022: Biodegradable biopolymer nanocomposite that detects relative humidity can monitor packed food freshness

A newly developed biodegradable, biopolymer nanocomposite which can detect relative humidity can find application as smart packaging materials, especially for the food industry. 

The food industry has an increasing need for non-toxic, biodegradable, low-cost, and environmentally friendly material for use as packaging material to replace petroleum-based material like plastics. Besides, it also needs smart and active packaging materials to detect and report food quality in a real-time fashion. Such smart and active packaging systems respond to signals while interacting with the food packaging environment. Perishable packed foods are easily damaged by the change in relative humidity.

Scientists from the Institute of Advanced Study in Science and Technology (IASST), an autonomous institute of the Department of Science and Technology led by Prof. Devashish Chowdhury, Professor in the Physical Sciences Division, and his INSPIRE Senior Research Fellow (SRF) student Mr. Sazzadur Rahman have developed a smart biodegradable biopolymer nanocomposite which can detect relative humidity. In this, two biopolymers, Guar Gum (a variety of beans obtained from plant) and Alginate (obtained from brown algae), were blended with carbon dots (nanomaterial) to make a nanocomposite film that was successfully used to detect relative humidity. The fabricated nanocomposite film was an excellent smart sensor based on the fluorescence ‘on-off’ mechanisms against humidity. Their research has been published in the International Journal of Biological Macromolecules.

The nanocomposite film shows change in fluorescence in presence of high humidity. Hence, the fabricated nanocomposite film can monitor the packed food freshness using just a UV light source. “Smart and active packaging can help consumers select a fresh product without breaking the pack. Such innovative packaging boosts sales and reduces consumers' time to identify fresh food products,” said Prof. Chowdhury.

5-Oct-2021: New biodegradable polymer fabricated using guar gum, and chitosan has high potential for packaging material

A team of Indian scientists have developed an environmentally friendly, non-toxic, biodegradable polymer using guar gum and chitosan, both of which are polysaccharides extracted from guar beans and shells of crab and shrimps. The fabricated guar gum-chitosan film having high water stability, high mechanical strength, and excellent resistance to harsh environmental conditions can potentially be used in packaging applications.

Polysaccharide is one of the biopolymers with high potential for use in synthesis of packaging material. However, due to some drawbacks of polysaccharides, such as low mechanical properties, high water-solubility, and low barrier properties, they are not preferred.

In order to overcome these challenges of polysaccharide, Dr. Devasish Chowdhury, Associate Professor, and Sazzadur Rahman, Inspire Junior Research Fellow, fabricated a guar gum-chitosan composite film which is a cross-linked polysaccharide without using any plasticizer with the help of a method called the solution casting method (a simple technique to make polymer films). The fabricated biopolymer composite film had high water stability, high mechanical strength, and excellent resistance to harsh environmental conditions. This work has been published recently in the journal ‘Carbohydrate Polymer Technologies and Applications’.

The researchers found that the fabricated crosslinked film did not dissolve in water even after 240 hours. In addition, the mechanical strength of crosslinked guar gum-chitosan composite film was higher compared to general biopolymer (Biopolymer are known to possess poor strength). The cross-linked guar gum-chitosan composite film was also highly water repellent or hydrophobic due to its high contact angle of 92.8º.  It had low water vapor permeability when compared with the film made only from chitosan.

The superior mechanical strength, water repellent properties, and resistance to harsh environmental conditions of the fabricated cross-linked guar gum-chitosan increase its potential of being used in packaging applications.