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Barnali Sutradhar

University of Utah, PhD in Materials Science and Engineering

EREF Scholar 2023

Polyethylene terephthalate (PET) is the most commonly and widely used thermoplastic polyester, with applications in soft drink bottles, textiles, plastic films, food packaging and insulation because of its transparent, mechanically stable, light weight, chemically stable and non-toxic properties. Only ~30% of waste polyethylene terephthalate (PET) is recycled, and the remaining are going to either landfill or ocean which in turn is detrimental to land and aquatic animals’ health. This 30% is recycled almost exclusively by mechanical reprocessing. During such reprocessing, the chemical structure of PET is often altered due to undesired side reactions, as a result, its performance decays. It degrades the material properties, and we don’t get high valued degraded products which can later be used for upcycling. So chemical recycling comes into play when we think about preserving the material properties. This project aims to degrade PET powder and bottles by the low-cost methanolysis process at room temperature using inexpensive group-I inorganic salts as catalysts and understand the mechanism and kinetics of the degradation process. Potassium carbonate has been used as the catalyst and DCM (dichloromethane) has been used as a cosolvent which accelerates the degradation process. Other group-I carbonate salts like rubidium and cesium carbonate have been used as well and they also worked well in degrading the PET. For the cosolvent, acetone and THF(Tetrahydrofuran) have also been used and interestingly both worked, and the degraded product DMT (Dimethyl Terephthalate) could be produced after 24 hours of the reaction. This project also covers the upcycling of PET which involves repolymerizing the degraded product DMT. Polyols have been made from the DMT using diols and potassium carbonate at 700C. In the later stage polyurethane can be synthesized from the polyols by reacting it with isocyanates. This polyurethane has so many applications in building and construction, transportation, furniture and bedding, appliances, packaging, textiles, fibers, footwears, electronics, and others. So, this project would show how from solid waste people can get such widely used products that too at low cost and minimal use of energy.


Barnali Sutradhar graduated from Bangladesh University of Engineering and Technology, Dhaka, Bangladesh with a Bachelor of Science degree in Materials and Metallurgical Engineering in September 2017. After her graduation, she continued her undergraduate research work and published two papers on fiber reinforced polypropylene composites. Barnali first came to the USA in September 2019 and joined the University of California, Riverside for her graduate studies. She earned her Master of Science degree in Materials Science and Engineering from UCR in June 2022. Currently she is pursuing her PhD degree in Materials Science and Engineering at the University of Utah and is doing extensive research work on the plastic recycling and waste management field.