Prof P P Kundu, Department of Chemical Engineering, IIT Roorkee, who is an expert in Polymer Technology has developed a thermoplastic starch that will be blended with LDPE, thereby making LDPE biodegradable.
The government of India has banned the use of certain types of polybags since July 2022, as these are non-biodegradable and considered to be a big hazard to the environment and with Prof Kundu’s technology India can soon have biodegradable polybags of its own.
India being agrarian in nature produces a lot of starch such as potato, rice, wheat, and maize, or corn starch and other starches are available in plenty which can help in the production of these bags.
Natural starch being crystalline cannot be blended with LDPE as its melting point is more than 250oC. So, it can be used as filler in LDPE. On the other hand, thermoplastic starch is a plasticized form of natural starch obtained from natural sources such as cassava, maize, potato, etc along with plasticizer. Thermoplastic starch is mainly amorphous, whereas ordinary starch is crystalline, explained the IIT.
The commonly used plasticizers are polyfunctional alcohols such as glycerol, and sorbitol along with some low molecular weight compounds capable of forming intermolecular hydrogen bonding such as water, formamide, etc. The starch and plasticizer in the presence of heat and constant agitation undergo gelatinization. In that process, the crystallinity of starch is sufficiently reduced, leading to an amorphous structure. Due to its amorphous character, it can be blended with LDPE, the IT explained.
IIT Roorkee has transferred this technology to Noida-based Agrsar Innovatives LLP for manufacturing biodegradable polybags in large quantities. M/s Agrasar will commercially utilize the present technology for manufacturing biodegradable polybags in large quantities.
Prof Ajit Kumar Chaturvedi, Director of IIT Roorkee said “The developed technology is expected to have immense value in view of the large quantities of starch produced in India and the environment-friendly nature of the solution.”