Monitoring temperature by observation using naked eye on shape memory effect

• Main Author: Tan, Chin Hong
• Other Authors: Huang Weimin
• Format: Final Year Project
• Language: English
• Published: 2017
• Subjects: DRNTU::Engineering::Mechanical engineering
• Online Access: http://hdl.handle.net/10356/71774
• Institution: Nanyang Technological University

Shape memory materials (SMMs) are defined as smart materials that have the ability to recover to their original shape after deformation when the right stimulus is applied such as heat, water, electricity, magnetic field, and so on. This unique phenomenon is known as shape memory effect (SME). SMMs have aroused great attentions from both industrial and academic researchers due to their useful functionality. In this report, the SMEs of two different shape memory polymers which are Ethylene Vinyl Acetate foam (EVA foam) and hybrid of silicone and thermoplastic polyurethane (Silicone60TPU262A40) have been investigated. It proved that the programming temperature has strong influences on the shape recovery upon heating. It also revealed that a shape recovery ratio of about 80% or more is always achievable at the programming temperature within the transition range of both materials. It is concluded that the shape recovery ability for both materials are excellent. Surface measurement is required for monitoring the shape recovery. Normally, a surface scanning machine is used to measure the surface profile in a scientific way which provides quantitative data for examining the surface changes during the shape recovery process, but it is time consuming. Therefore, it would be beneficial to find out a faster way to monitor the shape recovery without using machine. In this report, Moiré effect has been used as an assisting tool to help monitoring the shape recovery process by observation using naked eyes. It revealed that the complete shape recovery processes can be clearly seen with the help of Moiré pattern, and the tilt angles of 80° and 90° are identified as the optimal angles which provide better observation. In addition, a special characteristic of the hybrid of Silicone and TPU262A has been discovered where the pattern printed on the hybrid is able to diffuse over a period of time. It was proven that the diffusion time can be changed by adjusting the mass ratio of Silicone and TPU262A which has great potential to be implemented to the application where the indication of the expiry time is required such as temporary label.