Investigating the effects of cellulose nanocrystals and genipin on upcycled keratin films for packaging applications

• Main Author: Chan, Matthew Young
• Other Authors: Ng Kee Woei
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2024
• Subjects: Engineering; Bioplastics; Keratin; Cellulose; Sustainable materials; Packaging films
• Online Access: https://hdl.handle.net/10356/176112
• Institution: Nanyang Technological University

The global production of plastic waste has been steadily increasing over the years with a reported 460 million metric tonnes of plastic generated in 2019. Of this, only an average 9% of plastics get recycled annually while over 22% of plastics gets mismanaged and ends up in natural environments causing detrimental effects to the environment and its residing ecosystems. In this study, upcycled keratin is obtained using human hair waste via a modified Shindai method which isolates keratin intermediate filaments. The isolated keratin is then combined with reinforcing agents such as cellulose nanocrystals, and crosslinkers such as genipin. Keratin composite films are then fabricated via drop casting on to PTFE fibre mats and left at room temperature and pressure to dry. Fabricated films are then analysed using characterisation techniques to determine its chemical composition, mechanical properties, and hydrophobicity. The addition of CNCs have shown to improve the mechanical stability of the keratin film and increased the hydrophobicity of the film by reducing the amount of free volume within the composite. The 6CNC sample was shown to possess the highest mechanical strength and hydrophobicity (sample details can be found in table 1.) The addition of genipin as a crosslinker did not highlight any significant crosslinking based on FTIR analysis. However, there was a slight increase in hydrophobicity observed with the addition of genipin which can be attributed to the presence of non-covalent molecular interactions between the genipin molecules and the keratin chains. Biodegradation tests in soil and seawater environments were used to confirm biodegradability of the fabricated film samples, which revealed that the rate of degradation can be controlled by varying the amounts of cellulose nanocrystals and genipin. A higher concentration of CNCs allows for an increased rate of soil and seawater degradation. Additionally, the addition of genipin has shown to retard the rate of degradation in both setups. In summary, the degradability of keratin composite films, coupled with its potential to improve its mechanical properties, provides a greener alternative to current conventional packaging solutions.