Evaluation of recycled keratin-polyethylene-polypropylene biocomposites for 3D printing

• Main Author: Tan, Alvin Chong Siang
• Other Authors: Tan Lay Poh
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2023
• Subjects: Engineering::Materials::Composite materials
• Online Access: https://hdl.handle.net/10356/165711
• Institution: Nanyang Technological University

The increasing global production of plastics has led to environmental concerns on the harmful effects of plastic production and waste disposal. 3D printing has created unique opportunities in plastic recycling, allowing plastic waste to be reused for home commodity applications. Polyethylene and Polypropylene are among the most used polymers throughout the world. The abundance of such materials allows it to be easily obtained, and these thermoplastics can also undergo recycling processes with relatively low energy consumptions. Mechanical recycling is a simple and cost-effective method to recycle these polymers but will result in deteriorated material properties due to polymer thermal degradation. In search of recycled polymer blends that compensate for the loss of properties, this report discusses the use of keratin biofiller as a reinforcing additive to the recycled plastic. Keratin is sourced from chicken feathers, which are also waste products from agricultural industries. This research aims to create recycled polymer blends with better properties, while addressing the sustainability issues of polymer and chicken feather waste disposal. Thermal characterization through Thermogravimetric Analysis and Differential Scanning Calorimetry, as well as mechanical characterization through Tensile and Izod Impact Testing, were used to evaluate the properties of the blends. In addition, Optical and Scanning Electron microscopy was used to investigate the materials morphology at the microscopic level. Keratin-polyethylene-polypropylene biocomposites were found to have slightly improved mechanical properties, but poorer impact strength. The thermal stability of the blends was reduced due to the presence of natural proteins. With the presence of keratin, crystallization temperatures and overall polymer crystallinity were improved in favour of 3D printing. It was found that the recycled materials may not be suitable for filament extrusion. Further work needs to be done to improve keratin’s thermal stability and compatibility to form functional biocomposite materials.