Processes for pigment separation from recycled thermoplastic polyurethane
Innovative chemical processes for separating pigments from recycled thermoplastic polyurethane, facilitating effective recycling and reducing environmental impact.
Overview
This solution addresses the challenge of recycling thermoplastic polyurethane (TPU) by focusing on the separation of stable, non-degradable pigments. These pigments pose significant obstacles during recycling due to contamination and quality degradation. Our process aims to cleave the auxochromes and chromophores in dyes, effectively discoloring them and facilitating more efficient recycling of TPU waste. With over 28.8 million tonnes of polyurethane produced annually, this innovation is crucial for managing waste and producing market-demanded products.
Technical specifications
Our approach involves a multi-stage process to effectively separate pigments:
- Oxidative Bleaching: Utilizes oxidizing agents like chlorine and ozone to break chromophore double bonds.
- Reductive Bleaching: Involves reducing agents such as sodium hydrosulphite to cleave azo groups in chromophores.
- Chemical Hydrolysis: Employs alkaline conditions to hydrolyze dye molecule bonds.
- Advanced Oxidation Processes (AOPs): Generates highly reactive species like hydroxyl radicals for dye degradation.
Following pigment removal, white pigments are added to enhance the white shade of the polymer, aiding in its recycling and recoloring.
Technology readiness level
This technology is currently at TRL 3, having been validated through analytical studies and chemical tests to demonstrate the mechanism of dye cleaving. Further development is necessary to optimize and scale the process for industrial applications.
About Mahatma Gandhi University
Mahatma Gandhi University is a comprehensive public state university on the 110‑acre Priyadarsini Hills campus in Kottayam, serving a broad network of affiliated colleges across central Kerala. Industry engagement is anchored by the Business Innovation and Incubation Centre, established in 2016 with seed support from the Government of Kerala, which provides pre‑incubation, startup mentoring, and IP services. The MGU Innovation Foundation runs technology‑business incubation facilities and programs that convene bootcamps, broker MoUs, and connect companies with faculty and student entrepreneurs; an MoU with Kerala’s Bio360 Life Sciences Park extends access to the regional cluster and commercialization pathways. Research is sustained by competitive national and state funding from agencies such as DST, DBT, CSIR, and ICMR. A dedicated IP and licensing pathway through BIIC supports patenting, licensing, and startup formation.
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